Re: Speed dblink using alternate libpq tuple storage
| От | Kyotaro HORIGUCHI |
|---|---|
| Тема | Re: Speed dblink using alternate libpq tuple storage |
| Дата | |
| Msg-id | 20120216.174934.80061891.horiguchi.kyotaro@oss.ntt.co.jp обсуждение исходный текст |
| Ответ на | Re: Speed dblink using alternate libpq tuple storage (Marko Kreen <markokr@gmail.com>) |
| Ответы |
Re: Speed dblink using alternate libpq tuple storage
(Marko Kreen <markokr@gmail.com>)
|
| Список | pgsql-hackers |
Hello,
I added the function PQskipRemainingResult() and use it in
dblink. This reduces the number of executing try-catch block from
the number of rows to one per query in dblink.
- fe-exec.c : new function PQskipRemainingResult.
- dblink.c : using PQskipRemainingResult in dblink_record_internal().
- libpq.sgml: documentation for PQskipRemainingResult and related change in RowProcessor.
> Instead I added simple feature: rowProcessor can return '2',
> in which case getAnotherTuple() does early exit without setting
> any error state. In user side it appears as PQisBusy() returned
> with TRUE result. All pointers stay valid, so callback can just
> stuff them into some temp area.
...
> It's included in main patch, but I also attached it as separate patch
> so that it can be examined separately and reverted if not acceptable.
This patch is based on the patch above and composed in the same
manner - main three patches include all modifications and the '2'
patch separately.
This patch is not rebased to the HEAD because the HEAD yields
error about the symbol LEAKPROOF...
regards,
--
Kyotaro Horiguchi
NTT Open Source Software Center
diff --git a/src/interfaces/libpq/#fe-protocol3.c# b/src/interfaces/libpq/#fe-protocol3.c#
new file mode 100644
index 0000000..8b7eed2
--- /dev/null
+++ b/src/interfaces/libpq/#fe-protocol3.c#
@@ -0,0 +1,1967 @@
+/*-------------------------------------------------------------------------
+ *
+ * fe-protocol3.c
+ * functions that are specific to frontend/backend protocol version 3
+ *
+ * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/interfaces/libpq/fe-protocol3.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <ctype.h>
+#include <fcntl.h>
+
+#include "libpq-fe.h"
+#include "libpq-int.h"
+
+#include "mb/pg_wchar.h"
+
+#ifdef WIN32
+#include "win32.h"
+#else
+#include <unistd.h>
+#include <netinet/in.h>
+#ifdef HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
+#include <arpa/inet.h>
+#endif
+
+
+/*
+ * This macro lists the backend message types that could be "long" (more
+ * than a couple of kilobytes).
+ */
+#define VALID_LONG_MESSAGE_TYPE(id) \
+ ((id) == 'T' || (id) == 'D' || (id) == 'd' || (id) == 'V' || \
+ (id) == 'E' || (id) == 'N' || (id) == 'A')
+
+
+static void handleSyncLoss(PGconn *conn, char id, int msgLength);
+static int getRowDescriptions(PGconn *conn);
+static int getParamDescriptions(PGconn *conn);
+static int getAnotherTuple(PGconn *conn, int msgLength);
+static int getParameterStatus(PGconn *conn);
+static int getNotify(PGconn *conn);
+static int getCopyStart(PGconn *conn, ExecStatusType copytype);
+static int getReadyForQuery(PGconn *conn);
+static void reportErrorPosition(PQExpBuffer msg, const char *query,
+ int loc, int encoding);
+static int build_startup_packet(const PGconn *conn, char *packet,
+ const PQEnvironmentOption *options);
+
+
+/*
+ * parseInput: if appropriate, parse input data from backend
+ * until input is exhausted or a stopping state is reached.
+ * Note that this function will NOT attempt to read more data from the backend.
+ */
+void
+pqParseInput3(PGconn *conn)
+{
+ char id;
+ int msgLength;
+ int avail;
+
+ /*
+ * Loop to parse successive complete messages available in the buffer.
+ */
+ for (;;)
+ {
+ /*
+ * Try to read a message. First get the type code and length. Return
+ * if not enough data.
+ */
+ conn->inCursor = conn->inStart;
+ if (pqGetc(&id, conn))
+ return;
+ if (pqGetInt(&msgLength, 4, conn))
+ return;
+
+ /*
+ * Try to validate message type/length here. A length less than 4 is
+ * definitely broken. Large lengths should only be believed for a few
+ * message types.
+ */
+ if (msgLength < 4)
+ {
+ handleSyncLoss(conn, id, msgLength);
+ return;
+ }
+ if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
+ {
+ handleSyncLoss(conn, id, msgLength);
+ return;
+ }
+
+ /*
+ * Can't process if message body isn't all here yet.
+ */
+ msgLength -= 4;
+ avail = conn->inEnd - conn->inCursor;
+ if (avail < msgLength)
+ {
+ /*
+ * Before returning, enlarge the input buffer if needed to hold
+ * the whole message. This is better than leaving it to
+ * pqReadData because we can avoid multiple cycles of realloc()
+ * when the message is large; also, we can implement a reasonable
+ * recovery strategy if we are unable to make the buffer big
+ * enough.
+ */
+ if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
+ conn))
+ {
+ /*
+ * XXX add some better recovery code... plan is to skip over
+ * the message using its length, then report an error. For the
+ * moment, just treat this like loss of sync (which indeed it
+ * might be!)
+ */
+ handleSyncLoss(conn, id, msgLength);
+ }
+ return;
+ }
+
+ /*
+ * NOTIFY and NOTICE messages can happen in any state; always process
+ * them right away.
+ *
+ * Most other messages should only be processed while in BUSY state.
+ * (In particular, in READY state we hold off further parsing until
+ * the application collects the current PGresult.)
+ *
+ * However, if the state is IDLE then we got trouble; we need to deal
+ * with the unexpected message somehow.
+ *
+ * ParameterStatus ('S') messages are a special case: in IDLE state we
+ * must process 'em (this case could happen if a new value was adopted
+ * from config file due to SIGHUP), but otherwise we hold off until
+ * BUSY state.
+ */
+ if (id == 'A')
+ {
+ if (getNotify(conn))
+ return;
+ }
+ else if (id == 'N')
+ {
+ if (pqGetErrorNotice3(conn, false))
+ return;
+ }
+ else if (conn->asyncStatus != PGASYNC_BUSY)
+ {
+ /* If not IDLE state, just wait ... */
+ if (conn->asyncStatus != PGASYNC_IDLE)
+ return;
+
+ /*
+ * Unexpected message in IDLE state; need to recover somehow.
+ * ERROR messages are displayed using the notice processor;
+ * ParameterStatus is handled normally; anything else is just
+ * dropped on the floor after displaying a suitable warning
+ * notice. (An ERROR is very possibly the backend telling us why
+ * it is about to close the connection, so we don't want to just
+ * discard it...)
+ */
+ if (id == 'E')
+ {
+ if (pqGetErrorNotice3(conn, false /* treat as notice */ ))
+ return;
+ }
+ else if (id == 'S')
+ {
+ if (getParameterStatus(conn))
+ return;
+ }
+ else
+ {
+ pqInternalNotice(&conn->noticeHooks,
+ "message type 0x%02x arrived from server while idle",
+ id);
+ /* Discard the unexpected message */
+ conn->inCursor += msgLength;
+ }
+ }
+ else
+ {
+ /*
+ * In BUSY state, we can process everything.
+ */
+ switch (id)
+ {
+ case 'C': /* command complete */
+ if (pqGets(&conn->workBuffer, conn))
+ return;
+ if (conn->result == NULL)
+ {
+ conn->result = PQmakeEmptyPGresult(conn,
+ PGRES_COMMAND_OK);
+ if (!conn->result)
+ return;
+ }
+ strncpy(conn->result->cmdStatus, conn->workBuffer.data,
+ CMDSTATUS_LEN);
+ conn->asyncStatus = PGASYNC_READY;
+ break;
+ case 'E': /* error return */
+ if (pqGetErrorNotice3(conn, true))
+ return;
+ conn->asyncStatus = PGASYNC_READY;
+ break;
+ case 'Z': /* backend is ready for new query */
+ if (getReadyForQuery(conn))
+ return;
+ conn->asyncStatus = PGASYNC_IDLE;
+ break;
+ case 'I': /* empty query */
+ if (conn->result == NULL)
+ {
+ conn->result = PQmakeEmptyPGresult(conn,
+ PGRES_EMPTY_QUERY);
+ if (!conn->result)
+ return;
+ }
+ conn->asyncStatus = PGASYNC_READY;
+ break;
+ case '1': /* Parse Complete */
+ /* If we're doing PQprepare, we're done; else ignore */
+ if (conn->queryclass == PGQUERY_PREPARE)
+ {
+ if (conn->result == NULL)
+ {
+ conn->result = PQmakeEmptyPGresult(conn,
+ PGRES_COMMAND_OK);
+ if (!conn->result)
+ return;
+ }
+ conn->asyncStatus = PGASYNC_READY;
+ }
+ break;
+ case '2': /* Bind Complete */
+ case '3': /* Close Complete */
+ /* Nothing to do for these message types */
+ break;
+ case 'S': /* parameter status */
+ if (getParameterStatus(conn))
+ return;
+ break;
+ case 'K': /* secret key data from the backend */
+
+ /*
+ * This is expected only during backend startup, but it's
+ * just as easy to handle it as part of the main loop.
+ * Save the data and continue processing.
+ */
+ if (pqGetInt(&(conn->be_pid), 4, conn))
+ return;
+ if (pqGetInt(&(conn->be_key), 4, conn))
+ return;
+ break;
+ case 'T': /* Row Description */
+ if (conn->result == NULL ||
+ conn->queryclass == PGQUERY_DESCRIBE)
+ {
+ /* First 'T' in a query sequence */
+ if (getRowDescriptions(conn))
+ return;
+
+ /*
+ * If we're doing a Describe, we're ready to pass the
+ * result back to the client.
+ */
+ if (conn->queryclass == PGQUERY_DESCRIBE)
+ conn->asyncStatus = PGASYNC_READY;
+ }
+ else
+ {
+ /*
+ * A new 'T' message is treated as the start of
+ * another PGresult. (It is not clear that this is
+ * really possible with the current backend.) We stop
+ * parsing until the application accepts the current
+ * result.
+ */
+ conn->asyncStatus = PGASYNC_READY;
+ return;
+ }
+ break;
+ case 'n': /* No Data */
+
+ /*
+ * NoData indicates that we will not be seeing a
+ * RowDescription message because the statement or portal
+ * inquired about doesn't return rows.
+ *
+ * If we're doing a Describe, we have to pass something
+ * back to the client, so set up a COMMAND_OK result,
+ * instead of TUPLES_OK. Otherwise we can just ignore
+ * this message.
+ */
+ if (conn->queryclass == PGQUERY_DESCRIBE)
+ {
+ if (conn->result == NULL)
+ {
+ conn->result = PQmakeEmptyPGresult(conn,
+ PGRES_COMMAND_OK);
+ if (!conn->result)
+ return;
+ }
+ conn->asyncStatus = PGASYNC_READY;
+ }
+ break;
+ case 't': /* Parameter Description */
+ if (getParamDescriptions(conn))
+ return;
+ break;
+ case 'D': /* Data Row */
+ if (conn->result != NULL &&
+ conn->result->resultStatus == PGRES_TUPLES_OK)
+ {
+ /* Read another tuple of a normal query response */
+ if (getAnotherTuple(conn, msgLength))
+ return;
+ }
+ else if (conn->result != NULL &&
+ conn->result->resultStatus == PGRES_FATAL_ERROR)
+ {
+ /*
+ * We've already choked for some reason. Just discard
+ * tuples till we get to the end of the query.
+ */
+ conn->inCursor += msgLength;
+ }
+ else
+ {
+ /* Set up to report error at end of query */
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("server sent data (\"D\" message) without prior row
description(\"T\" message)\n"));
+ pqSaveErrorResult(conn);
+ /* Discard the unexpected message */
+ conn->inCursor += msgLength;
+ }
+ break;
+ case 'G': /* Start Copy In */
+ if (getCopyStart(conn, PGRES_COPY_IN))
+ return;
+ conn->asyncStatus = PGASYNC_COPY_IN;
+ break;
+ case 'H': /* Start Copy Out */
+ if (getCopyStart(conn, PGRES_COPY_OUT))
+ return;
+ conn->asyncStatus = PGASYNC_COPY_OUT;
+ conn->copy_already_done = 0;
+ break;
+ case 'W': /* Start Copy Both */
+ if (getCopyStart(conn, PGRES_COPY_BOTH))
+ return;
+ conn->asyncStatus = PGASYNC_COPY_BOTH;
+ conn->copy_already_done = 0;
+ break;
+ case 'd': /* Copy Data */
+
+ /*
+ * If we see Copy Data, just silently drop it. This would
+ * only occur if application exits COPY OUT mode too
+ * early.
+ */
+ conn->inCursor += msgLength;
+ break;
+ case 'c': /* Copy Done */
+
+ /*
+ * If we see Copy Done, just silently drop it. This is
+ * the normal case during PQendcopy. We will keep
+ * swallowing data, expecting to see command-complete for
+ * the COPY command.
+ */
+ break;
+ default:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext(
+ "unexpected response from server; first received character was
\"%c\"\n"),
+ id);
+ /* build an error result holding the error message */
+ pqSaveErrorResult(conn);
+ /* not sure if we will see more, so go to ready state */
+ conn->asyncStatus = PGASYNC_READY;
+ /* Discard the unexpected message */
+ conn->inCursor += msgLength;
+ break;
+ } /* switch on protocol character */
+ }
+ /* Successfully consumed this message */
+ if (conn->inCursor == conn->inStart + 5 + msgLength)
+ {
+ /* Normal case: parsing agrees with specified length */
+ conn->inStart = conn->inCursor;
+ }
+ else
+ {
+ /* Trouble --- report it */
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("message contents do not agree with length in message type \"%c\"\n"),
+ id);
+ /* build an error result holding the error message */
+ pqSaveErrorResult(conn);
+ conn->asyncStatus = PGASYNC_READY;
+ /* trust the specified message length as what to skip */
+ conn->inStart += 5 + msgLength;
+ }
+ }
+}
+
+/*
+ * handleSyncLoss: clean up after loss of message-boundary sync
+ *
+ * There isn't really a lot we can do here except abandon the connection.
+ */
+static void
+handleSyncLoss(PGconn *conn, char id, int msgLength)
+{
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext(
+ "lost synchronization with server: got message type \"%c\", length %d\n"),
+ id, msgLength);
+ /* build an error result holding the error message */
+ pqSaveErrorResult(conn);
+ conn->asyncStatus = PGASYNC_READY; /* drop out of GetResult wait loop */
+
+ pqsecure_close(conn);
+ closesocket(conn->sock);
+ conn->sock = -1;
+ conn->status = CONNECTION_BAD; /* No more connection to backend */
+}
+
+/*
+ * parseInput subroutine to read a 'T' (row descriptions) message.
+ * We'll build a new PGresult structure (unless called for a Describe
+ * command for a prepared statement) containing the attribute data.
+ * Returns: 0 if completed message, EOF if not enough data yet.
+ *
+ * Note that if we run out of data, we have to release the partially
+ * constructed PGresult, and rebuild it again next time. Fortunately,
+ * that shouldn't happen often, since 'T' messages usually fit in a packet.
+ */
+static int
+getRowDescriptions(PGconn *conn)
+{
+ PGresult *result;
+ int nfields;
+ int i;
+
+ /*
+ * When doing Describe for a prepared statement, there'll already be a
+ * PGresult created by getParamDescriptions, and we should fill data into
+ * that. Otherwise, create a new, empty PGresult.
+ */
+ if (conn->queryclass == PGQUERY_DESCRIBE)
+ {
+ if (conn->result)
+ result = conn->result;
+ else
+ result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
+ }
+ else
+ result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
+ if (!result)
+ goto failure;
+
+ /* parseInput already read the 'T' label and message length. */
+ /* the next two bytes are the number of fields */
+ if (pqGetInt(&(result->numAttributes), 2, conn))
+ goto failure;
+ nfields = result->numAttributes;
+
+ /* allocate space for the attribute descriptors */
+ if (nfields > 0)
+ {
+ result->attDescs = (PGresAttDesc *)
+ pqResultAlloc(result, nfields * sizeof(PGresAttDesc), TRUE);
+ if (!result->attDescs)
+ goto failure;
+ MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
+ }
+
+ /* result->binary is true only if ALL columns are binary */
+ result->binary = (nfields > 0) ? 1 : 0;
+
+ /* get type info */
+ for (i = 0; i < nfields; i++)
+ {
+ int tableid;
+ int columnid;
+ int typid;
+ int typlen;
+ int atttypmod;
+ int format;
+
+ if (pqGets(&conn->workBuffer, conn) ||
+ pqGetInt(&tableid, 4, conn) ||
+ pqGetInt(&columnid, 2, conn) ||
+ pqGetInt(&typid, 4, conn) ||
+ pqGetInt(&typlen, 2, conn) ||
+ pqGetInt(&atttypmod, 4, conn) ||
+ pqGetInt(&format, 2, conn))
+ {
+ goto failure;
+ }
+
+ /*
+ * Since pqGetInt treats 2-byte integers as unsigned, we need to
+ * coerce these results to signed form.
+ */
+ columnid = (int) ((int16) columnid);
+ typlen = (int) ((int16) typlen);
+ format = (int) ((int16) format);
+
+ result->attDescs[i].name = pqResultStrdup(result,
+ conn->workBuffer.data);
+ if (!result->attDescs[i].name)
+ goto failure;
+ result->attDescs[i].tableid = tableid;
+ result->attDescs[i].columnid = columnid;
+ result->attDescs[i].format = format;
+ result->attDescs[i].typid = typid;
+ result->attDescs[i].typlen = typlen;
+ result->attDescs[i].atttypmod = atttypmod;
+
+ if (format != 1)
+ result->binary = 0;
+ }
+
+ /* Success! */
+ conn->result = result;
+ return 0;
+
+failure:
+
+ /*
+ * Discard incomplete result, unless it's from getParamDescriptions.
+ *
+ * Note that if we hit a bufferload boundary while handling the
+ * describe-statement case, we'll forget any PGresult space we just
+ * allocated, and then reallocate it on next try. This will bloat the
+ * PGresult a little bit but the space will be freed at PQclear, so it
+ * doesn't seem worth trying to be smarter.
+ */
+ if (result != conn->result)
+ PQclear(result);
+ return EOF;
+}
+
+/*
+ * parseInput subroutine to read a 't' (ParameterDescription) message.
+ * We'll build a new PGresult structure containing the parameter data.
+ * Returns: 0 if completed message, EOF if not enough data yet.
+ *
+ * Note that if we run out of data, we have to release the partially
+ * constructed PGresult, and rebuild it again next time. Fortunately,
+ * that shouldn't happen often, since 't' messages usually fit in a packet.
+ */
+static int
+getParamDescriptions(PGconn *conn)
+{
+ PGresult *result;
+ int nparams;
+ int i;
+
+ result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
+ if (!result)
+ goto failure;
+
+ /* parseInput already read the 't' label and message length. */
+ /* the next two bytes are the number of parameters */
+ if (pqGetInt(&(result->numParameters), 2, conn))
+ goto failure;
+ nparams = result->numParameters;
+
+ /* allocate space for the parameter descriptors */
+ if (nparams > 0)
+ {
+ result->paramDescs = (PGresParamDesc *)
+ pqResultAlloc(result, nparams * sizeof(PGresParamDesc), TRUE);
+ if (!result->paramDescs)
+ goto failure;
+ MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc));
+ }
+
+ /* get parameter info */
+ for (i = 0; i < nparams; i++)
+ {
+ int typid;
+
+ if (pqGetInt(&typid, 4, conn))
+ goto failure;
+ result->paramDescs[i].typid = typid;
+ }
+
+ /* Success! */
+ conn->result = result;
+ return 0;
+
+failure:
+ PQclear(result);
+ return EOF;
+}
+
+/*
+ * parseInput subroutine to read a 'D' (row data) message.
+ * We add another tuple to the existing PGresult structure.
+ * Returns: 0 if completed message, EOF if error or not enough data yet.
+ *
+ * Note that if we run out of data, we have to suspend and reprocess
+ * the message after more data is received. We keep a partially constructed
+ * tuple in conn->curTuple, and avoid reallocating already-allocated storage.
+ */
+static int
+getAnotherTuple(PGconn *conn, int msgLength)
+{
+ PGresult *result = conn->result;
+ int nfields = result->numAttributes;
+ PGrowValue rowval[result->numAttributes + 1];
+ int tupnfields; /* # fields from tuple */
+ int vlen; /* length of the current field value */
+ int i;
+
+ /* Allocate tuple space if first time for this data message */
+ /* Get the field count and make sure it's what we expect */
+ if (pqGetInt(&tupnfields, 2, conn))
+ return EOF;
+
+ if (tupnfields != nfields)
+ {
+ /* Replace partially constructed result with an error result */
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("unexpected field count in \"D\" message\n"));
+ pqSaveErrorResult(conn);
+ /* Discard the failed message by pretending we read it */
+ conn->inCursor = conn->inStart + 5 + msgLength;
+ return 0;
+ }
+
+ /* Scan the fields */
+ for (i = 0; i < nfields; i++)
+ {
+ /* get the value length */
+ if (pqGetInt(&vlen, 4, conn))
+ return EOF;
+ if (vlen == -1)
+ vlen = NULL_LEN;
+ else if (vlen < 0)
+ vlen = 0;
+
+ /*
+ * Buffer content may be shifted on reloading additional
+ * data. So we must set all pointers on every scan.
+ *
+ * rowval[i].value always points to the next address of the
+ * length field even if the value length is zero or the value
+ * is NULL for the access safety.
+ */
+ rowval[i].value = conn->inBuffer + conn->inCursor;
+ rowval[i].len = vlen;
+
+ /* Skip to the next length field */
+ if (vlen > 0 && pqSkipnchar(vlen, conn))
+ return EOF;
+ }
+
+ /*
+ * Set rowval[nfields] for the access safety. We can estimate the
+ * length of the buffer to store by
+ *
+ * rowval[nfields].value - rowval[0].value - 4 * nfields.
+ */
+ rowval[nfields].value = conn->inBuffer + conn->inCursor;
+ rowval[nfields].len = NULL_LEN;
+
+ /* Success! Pass the completed row values to rowProcessor */
+ if (!result->rowProcessor(result, result->rowProcessorParam, rowval))
+ goto rowProcessError;
+
+ /* Free garbage error message. */
+ if (result->rowProcessorErrMes)
+ {
+ free(result->rowProcessorErrMes);
+ result->rowProcessorErrMes = NULL;
+ }
+
+ return 0;
+
+rowProcessError:
+
+ /*
+ * Replace partially constructed result with an error result. First
+ * discard the old result to try to win back some memory.
+ */
+ pqClearAsyncResult(conn);
+ resetPQExpBuffer(&conn->errorMessage);
+
+ /*
+ * If error message is passed from addTupleFunc, set it into
+ * PGconn, assume out of memory if not.
+ */
+ appendPQExpBufferStr(&conn->errorMessage,
+ libpq_gettext(result->rowProcessorErrMes ?
+ result->rowProcessorErrMes :
+ "out of memory for query result\n"));
+ if (result->rowProcessorErrMes)
+ {
+o free(result->rowProcessorErrMes);
+ result->rowProcessorErrMes = NULL;
+ }
+ pqSaveErrorResult(conn);
+
+ /* Discard the failed message by pretending we read it */
+ conn->inCursor = conn->inStart + 5 + msgLength;
+ return 0;
+}
+
+
+/*
+ * Attempt to read an Error or Notice response message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'E' or 'N' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ * returns EOF if not enough data.
+ */
+int
+pqGetErrorNotice3(PGconn *conn, bool isError)
+{
+ PGresult *res = NULL;
+ PQExpBufferData workBuf;
+ char id;
+ const char *val;
+ const char *querytext = NULL;
+ int querypos = 0;
+
+ /*
+ * Since the fields might be pretty long, we create a temporary
+ * PQExpBuffer rather than using conn->workBuffer. workBuffer is intended
+ * for stuff that is expected to be short. We shouldn't use
+ * conn->errorMessage either, since this might be only a notice.
+ */
+ initPQExpBuffer(&workBuf);
+
+ /*
+ * Make a PGresult to hold the accumulated fields. We temporarily lie
+ * about the result status, so that PQmakeEmptyPGresult doesn't uselessly
+ * copy conn->errorMessage.
+ */
+ res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY);
+ if (!res)
+ goto fail;
+ res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR;
+
+ /*
+ * Read the fields and save into res.
+ */
+ for (;;)
+ {
+ if (pqGetc(&id, conn))
+ goto fail;
+ if (id == '\0')
+ break; /* terminator found */
+ if (pqGets(&workBuf, conn))
+ goto fail;
+ pqSaveMessageField(res, id, workBuf.data);
+ }
+
+ /*
+ * Now build the "overall" error message for PQresultErrorMessage.
+ *
+ * Also, save the SQLSTATE in conn->last_sqlstate.
+ */
+ resetPQExpBuffer(&workBuf);
+ val = PQresultErrorField(res, PG_DIAG_SEVERITY);
+ if (val)
+ appendPQExpBuffer(&workBuf, "%s: ", val);
+ val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
+ if (val)
+ {
+ if (strlen(val) < sizeof(conn->last_sqlstate))
+ strcpy(conn->last_sqlstate, val);
+ if (conn->verbosity == PQERRORS_VERBOSE)
+ appendPQExpBuffer(&workBuf, "%s: ", val);
+ }
+ val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
+ if (val)
+ appendPQExpBufferStr(&workBuf, val);
+ val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION);
+ if (val)
+ {
+ if (conn->verbosity != PQERRORS_TERSE && conn->last_query != NULL)
+ {
+ /* emit position as a syntax cursor display */
+ querytext = conn->last_query;
+ querypos = atoi(val);
+ }
+ else
+ {
+ /* emit position as text addition to primary message */
+ /* translator: %s represents a digit string */
+ appendPQExpBuffer(&workBuf, libpq_gettext(" at character %s"),
+ val);
+ }
+ }
+ else
+ {
+ val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION);
+ if (val)
+ {
+ querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
+ if (conn->verbosity != PQERRORS_TERSE && querytext != NULL)
+ {
+ /* emit position as a syntax cursor display */
+ querypos = atoi(val);
+ }
+ else
+ {
+ /* emit position as text addition to primary message */
+ /* translator: %s represents a digit string */
+ appendPQExpBuffer(&workBuf, libpq_gettext(" at character %s"),
+ val);
+ }
+ }
+ }
+ appendPQExpBufferChar(&workBuf, '\n');
+ if (conn->verbosity != PQERRORS_TERSE)
+ {
+ if (querytext && querypos > 0)
+ reportErrorPosition(&workBuf, querytext, querypos,
+ conn->client_encoding);
+ val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
+ if (val)
+ appendPQExpBuffer(&workBuf, libpq_gettext("DETAIL: %s\n"), val);
+ val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
+ if (val)
+ appendPQExpBuffer(&workBuf, libpq_gettext("HINT: %s\n"), val);
+ val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
+ if (val)
+ appendPQExpBuffer(&workBuf, libpq_gettext("QUERY: %s\n"), val);
+ val = PQresultErrorField(res, PG_DIAG_CONTEXT);
+ if (val)
+ appendPQExpBuffer(&workBuf, libpq_gettext("CONTEXT: %s\n"), val);
+ }
+ if (conn->verbosity == PQERRORS_VERBOSE)
+ {
+ const char *valf;
+ const char *vall;
+
+ valf = PQresultErrorField(res, PG_DIAG_SOURCE_FILE);
+ vall = PQresultErrorField(res, PG_DIAG_SOURCE_LINE);
+ val = PQresultErrorField(res, PG_DIAG_SOURCE_FUNCTION);
+ if (val || valf || vall)
+ {
+ appendPQExpBufferStr(&workBuf, libpq_gettext("LOCATION: "));
+ if (val)
+ appendPQExpBuffer(&workBuf, libpq_gettext("%s, "), val);
+ if (valf && vall) /* unlikely we'd have just one */
+ appendPQExpBuffer(&workBuf, libpq_gettext("%s:%s"),
+ valf, vall);
+ appendPQExpBufferChar(&workBuf, '\n');
+ }
+ }
+
+ /*
+ * Either save error as current async result, or just emit the notice.
+ */
+ if (isError)
+ {
+ res->errMsg = pqResultStrdup(res, workBuf.data);
+ if (!res->errMsg)
+ goto fail;
+ pqClearAsyncResult(conn);
+ conn->result = res;
+ appendPQExpBufferStr(&conn->errorMessage, workBuf.data);
+ }
+ else
+ {
+ /* We can cheat a little here and not copy the message. */
+ res->errMsg = workBuf.data;
+ if (res->noticeHooks.noticeRec != NULL)
+ (*res->noticeHooks.noticeRec) (res->noticeHooks.noticeRecArg, res);
+ PQclear(res);
+ }
+
+ termPQExpBuffer(&workBuf);
+ return 0;
+
+fail:
+ PQclear(res);
+ termPQExpBuffer(&workBuf);
+ return EOF;
+}
+
+/*
+ * Add an error-location display to the error message under construction.
+ *
+ * The cursor location is measured in logical characters; the query string
+ * is presumed to be in the specified encoding.
+ */
+static void
+reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
+{
+#define DISPLAY_SIZE 60 /* screen width limit, in screen cols */
+#define MIN_RIGHT_CUT 10 /* try to keep this far away from EOL */
+
+ char *wquery;
+ int slen,
+ cno,
+ i,
+ *qidx,
+ *scridx,
+ qoffset,
+ scroffset,
+ ibeg,
+ iend,
+ loc_line;
+ bool mb_encoding,
+ beg_trunc,
+ end_trunc;
+
+ /* Convert loc from 1-based to 0-based; no-op if out of range */
+ loc--;
+ if (loc < 0)
+ return;
+
+ /* Need a writable copy of the query */
+ wquery = strdup(query);
+ if (wquery == NULL)
+ return; /* fail silently if out of memory */
+
+ /*
+ * Each character might occupy multiple physical bytes in the string, and
+ * in some Far Eastern character sets it might take more than one screen
+ * column as well. We compute the starting byte offset and starting
+ * screen column of each logical character, and store these in qidx[] and
+ * scridx[] respectively.
+ */
+
+ /* we need a safe allocation size... */
+ slen = strlen(wquery) + 1;
+
+ qidx = (int *) malloc(slen * sizeof(int));
+ if (qidx == NULL)
+ {
+ free(wquery);
+ return;
+ }
+ scridx = (int *) malloc(slen * sizeof(int));
+ if (scridx == NULL)
+ {
+ free(qidx);
+ free(wquery);
+ return;
+ }
+
+ /* We can optimize a bit if it's a single-byte encoding */
+ mb_encoding = (pg_encoding_max_length(encoding) != 1);
+
+ /*
+ * Within the scanning loop, cno is the current character's logical
+ * number, qoffset is its offset in wquery, and scroffset is its starting
+ * logical screen column (all indexed from 0). "loc" is the logical
+ * character number of the error location. We scan to determine loc_line
+ * (the 1-based line number containing loc) and ibeg/iend (first character
+ * number and last+1 character number of the line containing loc). Note
+ * that qidx[] and scridx[] are filled only as far as iend.
+ */
+ qoffset = 0;
+ scroffset = 0;
+ loc_line = 1;
+ ibeg = 0;
+ iend = -1; /* -1 means not set yet */
+
+ for (cno = 0; wquery[qoffset] != '\0'; cno++)
+ {
+ char ch = wquery[qoffset];
+
+ qidx[cno] = qoffset;
+ scridx[cno] = scroffset;
+
+ /*
+ * Replace tabs with spaces in the writable copy. (Later we might
+ * want to think about coping with their variable screen width, but
+ * not today.)
+ */
+ if (ch == '\t')
+ wquery[qoffset] = ' ';
+
+ /*
+ * If end-of-line, count lines and mark positions. Each \r or \n
+ * counts as a line except when \r \n appear together.
+ */
+ else if (ch == '\r' || ch == '\n')
+ {
+ if (cno < loc)
+ {
+ if (ch == '\r' ||
+ cno == 0 ||
+ wquery[qidx[cno - 1]] != '\r')
+ loc_line++;
+ /* extract beginning = last line start before loc. */
+ ibeg = cno + 1;
+ }
+ else
+ {
+ /* set extract end. */
+ iend = cno;
+ /* done scanning. */
+ break;
+ }
+ }
+
+ /* Advance */
+ if (mb_encoding)
+ {
+ int w;
+
+ w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
+ /* treat any non-tab control chars as width 1 */
+ if (w <= 0)
+ w = 1;
+ scroffset += w;
+ qoffset += pg_encoding_mblen(encoding, &wquery[qoffset]);
+ }
+ else
+ {
+ /* We assume wide chars only exist in multibyte encodings */
+ scroffset++;
+ qoffset++;
+ }
+ }
+ /* Fix up if we didn't find an end-of-line after loc */
+ if (iend < 0)
+ {
+ iend = cno; /* query length in chars, +1 */
+ qidx[iend] = qoffset;
+ scridx[iend] = scroffset;
+ }
+
+ /* Print only if loc is within computed query length */
+ if (loc <= cno)
+ {
+ /* If the line extracted is too long, we truncate it. */
+ beg_trunc = false;
+ end_trunc = false;
+ if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+ {
+ /*
+ * We first truncate right if it is enough. This code might be
+ * off a space or so on enforcing MIN_RIGHT_CUT if there's a wide
+ * character right there, but that should be okay.
+ */
+ if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT)
+ {
+ while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+ iend--;
+ end_trunc = true;
+ }
+ else
+ {
+ /* Truncate right if not too close to loc. */
+ while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend])
+ {
+ iend--;
+ end_trunc = true;
+ }
+
+ /* Truncate left if still too long. */
+ while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+ {
+ ibeg++;
+ beg_trunc = true;
+ }
+ }
+ }
+
+ /* truncate working copy at desired endpoint */
+ wquery[qidx[iend]] = '\0';
+
+ /* Begin building the finished message. */
+ i = msg->len;
+ appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line);
+ if (beg_trunc)
+ appendPQExpBufferStr(msg, "...");
+
+ /*
+ * While we have the prefix in the msg buffer, compute its screen
+ * width.
+ */
+ scroffset = 0;
+ for (; i < msg->len; i += pg_encoding_mblen(encoding, &msg->data[i]))
+ {
+ int w = pg_encoding_dsplen(encoding, &msg->data[i]);
+
+ if (w <= 0)
+ w = 1;
+ scroffset += w;
+ }
+
+ /* Finish up the LINE message line. */
+ appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]);
+ if (end_trunc)
+ appendPQExpBufferStr(msg, "...");
+ appendPQExpBufferChar(msg, '\n');
+
+ /* Now emit the cursor marker line. */
+ scroffset += scridx[loc] - scridx[ibeg];
+ for (i = 0; i < scroffset; i++)
+ appendPQExpBufferChar(msg, ' ');
+ appendPQExpBufferChar(msg, '^');
+ appendPQExpBufferChar(msg, '\n');
+ }
+
+ /* Clean up. */
+ free(scridx);
+ free(qidx);
+ free(wquery);
+}
+
+
+/*
+ * Attempt to read a ParameterStatus message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'S' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ * returns EOF if not enough data.
+ */
+static int
+getParameterStatus(PGconn *conn)
+{
+ PQExpBufferData valueBuf;
+
+ /* Get the parameter name */
+ if (pqGets(&conn->workBuffer, conn))
+ return EOF;
+ /* Get the parameter value (could be large) */
+ initPQExpBuffer(&valueBuf);
+ if (pqGets(&valueBuf, conn))
+ {
+ termPQExpBuffer(&valueBuf);
+ return EOF;
+ }
+ /* And save it */
+ pqSaveParameterStatus(conn, conn->workBuffer.data, valueBuf.data);
+ termPQExpBuffer(&valueBuf);
+ return 0;
+}
+
+
+/*
+ * Attempt to read a Notify response message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'A' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed Notify message.
+ * returns EOF if not enough data.
+ */
+static int
+getNotify(PGconn *conn)
+{
+ int be_pid;
+ char *svname;
+ int nmlen;
+ int extralen;
+ PGnotify *newNotify;
+
+ if (pqGetInt(&be_pid, 4, conn))
+ return EOF;
+ if (pqGets(&conn->workBuffer, conn))
+ return EOF;
+ /* must save name while getting extra string */
+ svname = strdup(conn->workBuffer.data);
+ if (!svname)
+ return EOF;
+ if (pqGets(&conn->workBuffer, conn))
+ {
+ free(svname);
+ return EOF;
+ }
+
+ /*
+ * Store the strings right after the PQnotify structure so it can all be
+ * freed at once. We don't use NAMEDATALEN because we don't want to tie
+ * this interface to a specific server name length.
+ */
+ nmlen = strlen(svname);
+ extralen = strlen(conn->workBuffer.data);
+ newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + extralen + 2);
+ if (newNotify)
+ {
+ newNotify->relname = (char *) newNotify + sizeof(PGnotify);
+ strcpy(newNotify->relname, svname);
+ newNotify->extra = newNotify->relname + nmlen + 1;
+ strcpy(newNotify->extra, conn->workBuffer.data);
+ newNotify->be_pid = be_pid;
+ newNotify->next = NULL;
+ if (conn->notifyTail)
+ conn->notifyTail->next = newNotify;
+ else
+ conn->notifyHead = newNotify;
+ conn->notifyTail = newNotify;
+ }
+
+ free(svname);
+ return 0;
+}
+
+/*
+ * getCopyStart - process CopyInResponse, CopyOutResponse or
+ * CopyBothResponse message
+ *
+ * parseInput already read the message type and length.
+ */
+static int
+getCopyStart(PGconn *conn, ExecStatusType copytype)
+{
+ PGresult *result;
+ int nfields;
+ int i;
+
+ result = PQmakeEmptyPGresult(conn, copytype);
+ if (!result)
+ goto failure;
+
+ if (pqGetc(&conn->copy_is_binary, conn))
+ goto failure;
+ result->binary = conn->copy_is_binary;
+ /* the next two bytes are the number of fields */
+ if (pqGetInt(&(result->numAttributes), 2, conn))
+ goto failure;
+ nfields = result->numAttributes;
+
+ /* allocate space for the attribute descriptors */
+ if (nfields > 0)
+ {
+ result->attDescs = (PGresAttDesc *)
+ pqResultAlloc(result, nfields * sizeof(PGresAttDesc), TRUE);
+ if (!result->attDescs)
+ goto failure;
+ MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
+ }
+
+ for (i = 0; i < nfields; i++)
+ {
+ int format;
+
+ if (pqGetInt(&format, 2, conn))
+ goto failure;
+
+ /*
+ * Since pqGetInt treats 2-byte integers as unsigned, we need to
+ * coerce these results to signed form.
+ */
+ format = (int) ((int16) format);
+ result->attDescs[i].format = format;
+ }
+
+ /* Success! */
+ conn->result = result;
+ return 0;
+
+failure:
+ PQclear(result);
+ return EOF;
+}
+
+/*
+ * getReadyForQuery - process ReadyForQuery message
+ */
+static int
+getReadyForQuery(PGconn *conn)
+{
+ char xact_status;
+
+ if (pqGetc(&xact_status, conn))
+ return EOF;
+ switch (xact_status)
+ {
+ case 'I':
+ conn->xactStatus = PQTRANS_IDLE;
+ break;
+ case 'T':
+ conn->xactStatus = PQTRANS_INTRANS;
+ break;
+ case 'E':
+ conn->xactStatus = PQTRANS_INERROR;
+ break;
+ default:
+ conn->xactStatus = PQTRANS_UNKNOWN;
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * getCopyDataMessage - fetch next CopyData message, process async messages
+ *
+ * Returns length word of CopyData message (> 0), or 0 if no complete
+ * message available, -1 if end of copy, -2 if error.
+ */
+static int
+getCopyDataMessage(PGconn *conn)
+{
+ char id;
+ int msgLength;
+ int avail;
+
+ for (;;)
+ {
+ /*
+ * Do we have the next input message? To make life simpler for async
+ * callers, we keep returning 0 until the next message is fully
+ * available, even if it is not Copy Data.
+ */
+ conn->inCursor = conn->inStart;
+ if (pqGetc(&id, conn))
+ return 0;
+ if (pqGetInt(&msgLength, 4, conn))
+ return 0;
+ if (msgLength < 4)
+ {
+ handleSyncLoss(conn, id, msgLength);
+ return -2;
+ }
+ avail = conn->inEnd - conn->inCursor;
+ if (avail < msgLength - 4)
+ {
+ /*
+ * Before returning, enlarge the input buffer if needed to hold
+ * the whole message. See notes in parseInput.
+ */
+ if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength - 4,
+ conn))
+ {
+ /*
+ * XXX add some better recovery code... plan is to skip over
+ * the message using its length, then report an error. For the
+ * moment, just treat this like loss of sync (which indeed it
+ * might be!)
+ */
+ handleSyncLoss(conn, id, msgLength);
+ return -2;
+ }
+ return 0;
+ }
+
+ /*
+ * If it's a legitimate async message type, process it. (NOTIFY
+ * messages are not currently possible here, but we handle them for
+ * completeness.) Otherwise, if it's anything except Copy Data,
+ * report end-of-copy.
+ */
+ switch (id)
+ {
+ case 'A': /* NOTIFY */
+ if (getNotify(conn))
+ return 0;
+ break;
+ case 'N': /* NOTICE */
+ if (pqGetErrorNotice3(conn, false))
+ return 0;
+ break;
+ case 'S': /* ParameterStatus */
+ if (getParameterStatus(conn))
+ return 0;
+ break;
+ case 'd': /* Copy Data, pass it back to caller */
+ return msgLength;
+ default: /* treat as end of copy */
+ return -1;
+ }
+
+ /* Drop the processed message and loop around for another */
+ conn->inStart = conn->inCursor;
+ }
+}
+
+/*
+ * PQgetCopyData - read a row of data from the backend during COPY OUT
+ * or COPY BOTH
+ *
+ * If successful, sets *buffer to point to a malloc'd row of data, and
+ * returns row length (always > 0) as result.
+ * Returns 0 if no row available yet (only possible if async is true),
+ * -1 if end of copy (consult PQgetResult), or -2 if error (consult
+ * PQerrorMessage).
+ */
+int
+pqGetCopyData3(PGconn *conn, char **buffer, int async)
+{
+ int msgLength;
+
+ for (;;)
+ {
+ /*
+ * Collect the next input message. To make life simpler for async
+ * callers, we keep returning 0 until the next message is fully
+ * available, even if it is not Copy Data.
+ */
+ msgLength = getCopyDataMessage(conn);
+ if (msgLength < 0)
+ {
+ /*
+ * On end-of-copy, exit COPY_OUT or COPY_BOTH mode and let caller
+ * read status with PQgetResult(). The normal case is that it's
+ * Copy Done, but we let parseInput read that. If error, we
+ * expect the state was already changed.
+ */
+ if (msgLength == -1)
+ conn->asyncStatus = PGASYNC_BUSY;
+ return msgLength; /* end-of-copy or error */
+ }
+ if (msgLength == 0)
+ {
+ /* Don't block if async read requested */
+ if (async)
+ return 0;
+ /* Need to load more data */
+ if (pqWait(TRUE, FALSE, conn) ||
+ pqReadData(conn) < 0)
+ return -2;
+ continue;
+ }
+
+ /*
+ * Drop zero-length messages (shouldn't happen anyway). Otherwise
+ * pass the data back to the caller.
+ */
+ msgLength -= 4;
+ if (msgLength > 0)
+ {
+ *buffer = (char *) malloc(msgLength + 1);
+ if (*buffer == NULL)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("out of memory\n"));
+ return -2;
+ }
+ memcpy(*buffer, &conn->inBuffer[conn->inCursor], msgLength);
+ (*buffer)[msgLength] = '\0'; /* Add terminating null */
+
+ /* Mark message consumed */
+ conn->inStart = conn->inCursor + msgLength;
+
+ return msgLength;
+ }
+
+ /* Empty, so drop it and loop around for another */
+ conn->inStart = conn->inCursor;
+ }
+}
+
+/*
+ * PQgetline - gets a newline-terminated string from the backend.
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqGetline3(PGconn *conn, char *s, int maxlen)
+{
+ int status;
+
+ if (conn->sock < 0 ||
+ conn->asyncStatus != PGASYNC_COPY_OUT ||
+ conn->copy_is_binary)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("PQgetline: not doing text COPY OUT\n"));
+ *s = '\0';
+ return EOF;
+ }
+
+ while ((status = PQgetlineAsync(conn, s, maxlen - 1)) == 0)
+ {
+ /* need to load more data */
+ if (pqWait(TRUE, FALSE, conn) ||
+ pqReadData(conn) < 0)
+ {
+ *s = '\0';
+ return EOF;
+ }
+ }
+
+ if (status < 0)
+ {
+ /* End of copy detected; gin up old-style terminator */
+ strcpy(s, "\\.");
+ return 0;
+ }
+
+ /* Add null terminator, and strip trailing \n if present */
+ if (s[status - 1] == '\n')
+ {
+ s[status - 1] = '\0';
+ return 0;
+ }
+ else
+ {
+ s[status] = '\0';
+ return 1;
+ }
+}
+
+/*
+ * PQgetlineAsync - gets a COPY data row without blocking.
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize)
+{
+ int msgLength;
+ int avail;
+
+ if (conn->asyncStatus != PGASYNC_COPY_OUT)
+ return -1; /* we are not doing a copy... */
+
+ /*
+ * Recognize the next input message. To make life simpler for async
+ * callers, we keep returning 0 until the next message is fully available
+ * even if it is not Copy Data. This should keep PQendcopy from blocking.
+ * (Note: unlike pqGetCopyData3, we do not change asyncStatus here.)
+ */
+ msgLength = getCopyDataMessage(conn);
+ if (msgLength < 0)
+ return -1; /* end-of-copy or error */
+ if (msgLength == 0)
+ return 0; /* no data yet */
+
+ /*
+ * Move data from libpq's buffer to the caller's. In the case where a
+ * prior call found the caller's buffer too small, we use
+ * conn->copy_already_done to remember how much of the row was already
+ * returned to the caller.
+ */
+ conn->inCursor += conn->copy_already_done;
+ avail = msgLength - 4 - conn->copy_already_done;
+ if (avail <= bufsize)
+ {
+ /* Able to consume the whole message */
+ memcpy(buffer, &conn->inBuffer[conn->inCursor], avail);
+ /* Mark message consumed */
+ conn->inStart = conn->inCursor + avail;
+ /* Reset state for next time */
+ conn->copy_already_done = 0;
+ return avail;
+ }
+ else
+ {
+ /* We must return a partial message */
+ memcpy(buffer, &conn->inBuffer[conn->inCursor], bufsize);
+ /* The message is NOT consumed from libpq's buffer */
+ conn->copy_already_done += bufsize;
+ return bufsize;
+ }
+}
+
+/*
+ * PQendcopy
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqEndcopy3(PGconn *conn)
+{
+ PGresult *result;
+
+ if (conn->asyncStatus != PGASYNC_COPY_IN &&
+ conn->asyncStatus != PGASYNC_COPY_OUT)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("no COPY in progress\n"));
+ return 1;
+ }
+
+ /* Send the CopyDone message if needed */
+ if (conn->asyncStatus == PGASYNC_COPY_IN)
+ {
+ if (pqPutMsgStart('c', false, conn) < 0 ||
+ pqPutMsgEnd(conn) < 0)
+ return 1;
+
+ /*
+ * If we sent the COPY command in extended-query mode, we must issue a
+ * Sync as well.
+ */
+ if (conn->queryclass != PGQUERY_SIMPLE)
+ {
+ if (pqPutMsgStart('S', false, conn) < 0 ||
+ pqPutMsgEnd(conn) < 0)
+ return 1;
+ }
+ }
+
+ /*
+ * make sure no data is waiting to be sent, abort if we are non-blocking
+ * and the flush fails
+ */
+ if (pqFlush(conn) && pqIsnonblocking(conn))
+ return 1;
+
+ /* Return to active duty */
+ conn->asyncStatus = PGASYNC_BUSY;
+ resetPQExpBuffer(&conn->errorMessage);
+
+ /*
+ * Non blocking connections may have to abort at this point. If everyone
+ * played the game there should be no problem, but in error scenarios the
+ * expected messages may not have arrived yet. (We are assuming that the
+ * backend's packetizing will ensure that CommandComplete arrives along
+ * with the CopyDone; are there corner cases where that doesn't happen?)
+ */
+ if (pqIsnonblocking(conn) && PQisBusy(conn))
+ return 1;
+
+ /* Wait for the completion response */
+ result = PQgetResult(conn);
+
+ /* Expecting a successful result */
+ if (result && result->resultStatus == PGRES_COMMAND_OK)
+ {
+ PQclear(result);
+ return 0;
+ }
+
+ /*
+ * Trouble. For backwards-compatibility reasons, we issue the error
+ * message as if it were a notice (would be nice to get rid of this
+ * silliness, but too many apps probably don't handle errors from
+ * PQendcopy reasonably). Note that the app can still obtain the error
+ * status from the PGconn object.
+ */
+ if (conn->errorMessage.len > 0)
+ {
+ /* We have to strip the trailing newline ... pain in neck... */
+ char svLast = conn->errorMessage.data[conn->errorMessage.len - 1];
+
+ if (svLast == '\n')
+ conn->errorMessage.data[conn->errorMessage.len - 1] = '\0';
+ pqInternalNotice(&conn->noticeHooks, "%s", conn->errorMessage.data);
+ conn->errorMessage.data[conn->errorMessage.len - 1] = svLast;
+ }
+
+ PQclear(result);
+
+ return 1;
+}
+
+
+/*
+ * PQfn - Send a function call to the POSTGRES backend.
+ *
+ * See fe-exec.c for documentation.
+ */
+PGresult *
+pqFunctionCall3(PGconn *conn, Oid fnid,
+ int *result_buf, int *actual_result_len,
+ int result_is_int,
+ const PQArgBlock *args, int nargs)
+{
+ bool needInput = false;
+ ExecStatusType status = PGRES_FATAL_ERROR;
+ char id;
+ int msgLength;
+ int avail;
+ int i;
+
+ /* PQfn already validated connection state */
+
+ if (pqPutMsgStart('F', false, conn) < 0 || /* function call msg */
+ pqPutInt(fnid, 4, conn) < 0 || /* function id */
+ pqPutInt(1, 2, conn) < 0 || /* # of format codes */
+ pqPutInt(1, 2, conn) < 0 || /* format code: BINARY */
+ pqPutInt(nargs, 2, conn) < 0) /* # of args */
+ {
+ pqHandleSendFailure(conn);
+ return NULL;
+ }
+
+ for (i = 0; i < nargs; ++i)
+ { /* len.int4 + contents */
+ if (pqPutInt(args[i].len, 4, conn))
+ {
+ pqHandleSendFailure(conn);
+ return NULL;
+ }
+ if (args[i].len == -1)
+ continue; /* it's NULL */
+
+ if (args[i].isint)
+ {
+ if (pqPutInt(args[i].u.integer, args[i].len, conn))
+ {
+ pqHandleSendFailure(conn);
+ return NULL;
+ }
+ }
+ else
+ {
+ if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
+ {
+ pqHandleSendFailure(conn);
+ return NULL;
+ }
+ }
+ }
+
+ if (pqPutInt(1, 2, conn) < 0) /* result format code: BINARY */
+ {
+ pqHandleSendFailure(conn);
+ return NULL;
+ }
+
+ if (pqPutMsgEnd(conn) < 0 ||
+ pqFlush(conn))
+ {
+ pqHandleSendFailure(conn);
+ return NULL;
+ }
+
+ for (;;)
+ {
+ if (needInput)
+ {
+ /* Wait for some data to arrive (or for the channel to close) */
+ if (pqWait(TRUE, FALSE, conn) ||
+ pqReadData(conn) < 0)
+ break;
+ }
+
+ /*
+ * Scan the message. If we run out of data, loop around to try again.
+ */
+ needInput = true;
+
+ conn->inCursor = conn->inStart;
+ if (pqGetc(&id, conn))
+ continue;
+ if (pqGetInt(&msgLength, 4, conn))
+ continue;
+
+ /*
+ * Try to validate message type/length here. A length less than 4 is
+ * definitely broken. Large lengths should only be believed for a few
+ * message types.
+ */
+ if (msgLength < 4)
+ {
+ handleSyncLoss(conn, id, msgLength);
+ break;
+ }
+ if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
+ {
+ handleSyncLoss(conn, id, msgLength);
+ break;
+ }
+
+ /*
+ * Can't process if message body isn't all here yet.
+ */
+ msgLength -= 4;
+ avail = conn->inEnd - conn->inCursor;
+ if (avail < msgLength)
+ {
+ /*
+ * Before looping, enlarge the input buffer if needed to hold the
+ * whole message. See notes in parseInput.
+ */
+ if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
+ conn))
+ {
+ /*
+ * XXX add some better recovery code... plan is to skip over
+ * the message using its length, then report an error. For the
+ * moment, just treat this like loss of sync (which indeed it
+ * might be!)
+ */
+ handleSyncLoss(conn, id, msgLength);
+ break;
+ }
+ continue;
+ }
+
+ /*
+ * We should see V or E response to the command, but might get N
+ * and/or A notices first. We also need to swallow the final Z before
+ * returning.
+ */
+ switch (id)
+ {
+ case 'V': /* function result */
+ if (pqGetInt(actual_result_len, 4, conn))
+ continue;
+ if (*actual_result_len != -1)
+ {
+ if (result_is_int)
+ {
+ if (pqGetInt(result_buf, *actual_result_len, conn))
+ continue;
+ }
+ else
+ {
+ if (pqGetnchar((char *) result_buf,
+ *actual_result_len,
+ conn))
+ continue;
+ }
+ }
+ /* correctly finished function result message */
+ status = PGRES_COMMAND_OK;
+ break;
+ case 'E': /* error return */
+ if (pqGetErrorNotice3(conn, true))
+ continue;
+ status = PGRES_FATAL_ERROR;
+ break;
+ case 'A': /* notify message */
+ /* handle notify and go back to processing return values */
+ if (getNotify(conn))
+ continue;
+ break;
+ case 'N': /* notice */
+ /* handle notice and go back to processing return values */
+ if (pqGetErrorNotice3(conn, false))
+ continue;
+ break;
+ case 'Z': /* backend is ready for new query */
+ if (getReadyForQuery(conn))
+ continue;
+ /* consume the message and exit */
+ conn->inStart += 5 + msgLength;
+ /* if we saved a result object (probably an error), use it */
+ if (conn->result)
+ return pqPrepareAsyncResult(conn);
+ return PQmakeEmptyPGresult(conn, status);
+ case 'S': /* parameter status */
+ if (getParameterStatus(conn))
+ continue;
+ break;
+ default:
+ /* The backend violates the protocol. */
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("protocol error: id=0x%x\n"),
+ id);
+ pqSaveErrorResult(conn);
+ /* trust the specified message length as what to skip */
+ conn->inStart += 5 + msgLength;
+ return pqPrepareAsyncResult(conn);
+ }
+ /* Completed this message, keep going */
+ /* trust the specified message length as what to skip */
+ conn->inStart += 5 + msgLength;
+ needInput = false;
+ }
+
+ /*
+ * We fall out of the loop only upon failing to read data.
+ * conn->errorMessage has been set by pqWait or pqReadData. We want to
+ * append it to any already-received error message.
+ */
+ pqSaveErrorResult(conn);
+ return pqPrepareAsyncResult(conn);
+}
+
+
+/*
+ * Construct startup packet
+ *
+ * Returns a malloc'd packet buffer, or NULL if out of memory
+ */
+char *
+pqBuildStartupPacket3(PGconn *conn, int *packetlen,
+ const PQEnvironmentOption *options)
+{
+ char *startpacket;
+
+ *packetlen = build_startup_packet(conn, NULL, options);
+ startpacket = (char *) malloc(*packetlen);
+ if (!startpacket)
+ return NULL;
+ *packetlen = build_startup_packet(conn, startpacket, options);
+ return startpacket;
+}
+
+/*
+ * Build a startup packet given a filled-in PGconn structure.
+ *
+ * We need to figure out how much space is needed, then fill it in.
+ * To avoid duplicate logic, this routine is called twice: the first time
+ * (with packet == NULL) just counts the space needed, the second time
+ * (with packet == allocated space) fills it in. Return value is the number
+ * of bytes used.
+ */
+static int
+build_startup_packet(const PGconn *conn, char *packet,
+ const PQEnvironmentOption *options)
+{
+ int packet_len = 0;
+ const PQEnvironmentOption *next_eo;
+ const char *val;
+
+ /* Protocol version comes first. */
+ if (packet)
+ {
+ ProtocolVersion pv = htonl(conn->pversion);
+
+ memcpy(packet + packet_len, &pv, sizeof(ProtocolVersion));
+ }
+ packet_len += sizeof(ProtocolVersion);
+
+ /* Add user name, database name, options */
+
+#define ADD_STARTUP_OPTION(optname, optval) \
+ do { \
+ if (packet) \
+ strcpy(packet + packet_len, optname); \
+ packet_len += strlen(optname) + 1; \
+ if (packet) \
+ strcpy(packet + packet_len, optval); \
+ packet_len += strlen(optval) + 1; \
+ } while(0)
+
+ if (conn->pguser && conn->pguser[0])
+ ADD_STARTUP_OPTION("user", conn->pguser);
+ if (conn->dbName && conn->dbName[0])
+ ADD_STARTUP_OPTION("database", conn->dbName);
+ if (conn->replication && conn->replication[0])
+ ADD_STARTUP_OPTION("replication", conn->replication);
+ if (conn->pgoptions && conn->pgoptions[0])
+ ADD_STARTUP_OPTION("options", conn->pgoptions);
+ if (conn->send_appname)
+ {
+ /* Use appname if present, otherwise use fallback */
+ val = conn->appname ? conn->appname : conn->fbappname;
+ if (val && val[0])
+ ADD_STARTUP_OPTION("application_name", val);
+ }
+
+ if (conn->client_encoding_initial && conn->client_encoding_initial[0])
+ ADD_STARTUP_OPTION("client_encoding", conn->client_encoding_initial);
+
+ /* Add any environment-driven GUC settings needed */
+ for (next_eo = options; next_eo->envName; next_eo++)
+ {
+ if ((val = getenv(next_eo->envName)) != NULL)
+ {
+ if (pg_strcasecmp(val, "default") != 0)
+ ADD_STARTUP_OPTION(next_eo->pgName, val);
+ }
+ }
+
+ /* Add trailing terminator */
+ if (packet)
+ packet[packet_len] = '\0';
+ packet_len++;
+
+ return packet_len;
+}
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index 1af8df6..23cf729 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -160,3 +160,6 @@ PQconnectStartParams 157PQping 158PQpingParams 159PQlibVersion
160
+PQsetRowProcessor 161
+PQsetRowProcessorErrMsg 162
+PQskipRemainingResults 163
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 27a9805..4605e49 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -2693,6 +2693,9 @@ makeEmptyPGconn(void) conn->wait_ssl_try = false;#endif
+ /* set default row processor */
+ PQsetRowProcessor(conn, NULL, NULL);
+ /* * We try to send at least 8K at a time, which is the usual size of pipe * buffers on Unix systems.
Thatway, when we are sending a large amount
@@ -2711,8 +2714,13 @@ makeEmptyPGconn(void) initPQExpBuffer(&conn->errorMessage);
initPQExpBuffer(&conn->workBuffer);
+ /* set up initial row buffer */
+ conn->rowBufLen = 32;
+ conn->rowBuf = (PGrowValue *)malloc(conn->rowBufLen * sizeof(PGrowValue));
+ if (conn->inBuffer == NULL || conn->outBuffer == NULL ||
+ conn->rowBuf == NULL || PQExpBufferBroken(&conn->errorMessage) ||
PQExpBufferBroken(&conn->workBuffer)) {
@@ -2814,6 +2822,8 @@ freePGconn(PGconn *conn) free(conn->inBuffer); if (conn->outBuffer)
free(conn->outBuffer);
+ if (conn->rowBuf)
+ free(conn->rowBuf); termPQExpBuffer(&conn->errorMessage); termPQExpBuffer(&conn->workBuffer);
@@ -5078,3 +5088,4 @@ PQregisterThreadLock(pgthreadlock_t newhandler) return prev;}
+
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index b743566..d7f3ae9 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -66,6 +66,7 @@ static PGresult *PQexecFinish(PGconn *conn);static int PQsendDescribe(PGconn *conn, char desc_type,
const char *desc_target);static int check_field_number(const PGresult *res, int field_num);
+static int pqAddRow(PGresult *res, void *param, PGrowValue *columns);/* ----------------
@@ -160,6 +161,7 @@ PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status) result->curBlock = NULL;
result->curOffset= 0; result->spaceLeft = 0;
+ result->rowProcessorErrMsg = NULL; if (conn) {
@@ -701,7 +703,6 @@ pqClearAsyncResult(PGconn *conn) if (conn->result) PQclear(conn->result); conn->result
=NULL;
- conn->curTuple = NULL;}/*
@@ -756,7 +757,6 @@ pqPrepareAsyncResult(PGconn *conn) */ res = conn->result; conn->result = NULL; /*
handingover ownership to caller */
- conn->curTuple = NULL; /* just in case */ if (!res) res = PQmakeEmptyPGresult(conn,
PGRES_FATAL_ERROR); else
@@ -828,6 +828,73 @@ pqInternalNotice(const PGNoticeHooks *hooks, const char *fmt,...)}/*
+ * PQsetRowProcessor
+ * Set function that copies column data out from network buffer.
+ */
+void
+PQsetRowProcessor(PGconn *conn, PQrowProcessor func, void *param)
+{
+ conn->rowProcessor = (func ? func : pqAddRow);
+ conn->rowProcessorParam = param;
+}
+
+/*
+ * PQsetRowProcessorErrMsg
+ * Set the error message pass back to the caller of RowProcessor.
+ *
+ * You can replace the previous message by alternative mes, or clear
+ * it with NULL.
+ */
+void
+PQsetRowProcessorErrMsg(PGresult *res, char *msg)
+{
+ if (msg)
+ res->rowProcessorErrMsg = pqResultStrdup(res, msg);
+ else
+ res->rowProcessorErrMsg = NULL;
+}
+
+/*
+ * pqAddRow
+ * add a row to the PGresult structure, growing it if necessary
+ * Returns TRUE if OK, FALSE if not enough memory to add the row.
+ */
+static int
+pqAddRow(PGresult *res, void *param, PGrowValue *columns)
+{
+ PGresAttValue *tup;
+ int nfields = res->numAttributes;
+ int i;
+
+ tup = (PGresAttValue *)
+ pqResultAlloc(res, nfields * sizeof(PGresAttValue), TRUE);
+ if (tup == NULL)
+ return FALSE;
+
+ for (i = 0 ; i < nfields ; i++)
+ {
+ tup[i].len = columns[i].len;
+ if (tup[i].len == NULL_LEN)
+ {
+ tup[i].value = res->null_field;
+ }
+ else
+ {
+ bool isbinary = (res->attDescs[i].format != 0);
+ tup[i].value = (char *)pqResultAlloc(res, tup[i].len + 1, isbinary);
+ if (tup[i].value == NULL)
+ return FALSE;
+
+ memcpy(tup[i].value, columns[i].value, tup[i].len);
+ /* We have to terminate this ourselves */
+ tup[i].value[tup[i].len] = '\0';
+ }
+ }
+
+ return pqAddTuple(res, tup);
+}
+
+/* * pqAddTuple * add a row pointer to the PGresult structure, growing it if necessary * Returns TRUE if OK,
FALSEif not enough memory to add the row
@@ -1223,7 +1290,6 @@ PQsendQueryStart(PGconn *conn) /* initialize async result-accumulation state */
conn->result= NULL;
- conn->curTuple = NULL; /* ready to send command message */ return true;
@@ -1832,6 +1898,22 @@ PQexecFinish(PGconn *conn)}/*
+ * Exaust remaining Data Rows in curret conn.
+ */
+PGresult *
+PQskipRemainingResults(PGconn *conn)
+{
+ pqClearAsyncResult(conn);
+
+ /* conn->result is set NULL in pqClearAsyncResult() */
+ pqSaveErrorResult(conn);
+
+ /* Skip over remaining Data Row messages */
+ PQgetResult(conn);
+}
+
+
+/* * PQdescribePrepared * Obtain information about a previously prepared statement *
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index ce0eac3..d11cb3c 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -219,6 +219,25 @@ pqGetnchar(char *s, size_t len, PGconn *conn)}/*
+ * pqGetnchar:
+ * skip len bytes in input buffer.
+ */
+int
+pqSkipnchar(size_t len, PGconn *conn)
+{
+ if (len > (size_t) (conn->inEnd - conn->inCursor))
+ return EOF;
+
+ conn->inCursor += len;
+
+ if (conn->Pfdebug)
+ fprintf(conn->Pfdebug, "From backend (%lu skipped)\n",
+ (unsigned long) len);
+
+ return 0;
+}
+
+/* * pqPutnchar: * write exactly len bytes to the current message */
diff --git a/src/interfaces/libpq/fe-protocol2.c b/src/interfaces/libpq/fe-protocol2.c
index a7c3899..ae4d7b0 100644
--- a/src/interfaces/libpq/fe-protocol2.c
+++ b/src/interfaces/libpq/fe-protocol2.c
@@ -569,6 +569,8 @@ pqParseInput2(PGconn *conn) /* Read another tuple of a normal query response
*/ if (getAnotherTuple(conn, FALSE)) return;
+ /* getAnotherTuple moves inStart itself */
+ continue; } else {
@@ -585,6 +587,8 @@ pqParseInput2(PGconn *conn) /* Read another tuple of a normal query response
*/ if (getAnotherTuple(conn, TRUE)) return;
+ /* getAnotherTuple moves inStart itself */
+ continue; } else {
@@ -703,52 +707,51 @@ failure:/* * parseInput subroutine to read a 'B' or 'D' (row data) message.
- * We add another tuple to the existing PGresult structure.
+ * It fills rowbuf with column pointers and then calls row processor. * Returns: 0 if completed message, EOF if error
ornot enough data yet. * * Note that if we run out of data, we have to suspend and reprocess
- * the message after more data is received. We keep a partially constructed
- * tuple in conn->curTuple, and avoid reallocating already-allocated storage.
+ * the message after more data is received. */static intgetAnotherTuple(PGconn *conn, bool binary){ PGresult
*result= conn->result; int nfields = result->numAttributes;
- PGresAttValue *tup;
+ PGrowValue *rowbuf; /* the backend sends us a bitmap of which attributes are null */ char
std_bitmap[64];/* used unless it doesn't fit */ char *bitmap = std_bitmap; int i;
+ int rp; size_t nbytes; /* the number of bytes in bitmap */ char bmap;
/* One byte of the bitmap */ int bitmap_index; /* Its index */ int bitcnt;
/* number of bits examined in current byte */ int vlen; /* length of the current field
value*/
+ /* resize row buffer if needed */
+ if (nfields > conn->rowBufLen)
+ {
+ rowbuf = realloc(conn->rowBuf, nfields * sizeof(PGrowValue));
+ if (!rowbuf)
+ goto rowProcessError;
+ conn->rowBuf = rowbuf;
+ conn->rowBufLen = nfields;
+ }
+ else
+ {
+ rowbuf = conn->rowBuf;
+ }
+ result->binary = binary;
- /* Allocate tuple space if first time for this data message */
- if (conn->curTuple == NULL)
+ if (binary) {
- conn->curTuple = (PGresAttValue *)
- pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
- if (conn->curTuple == NULL)
- goto outOfMemory;
- MemSet(conn->curTuple, 0, nfields * sizeof(PGresAttValue));
-
- /*
- * If it's binary, fix the column format indicators. We assume the
- * backend will consistently send either B or D, not a mix.
- */
- if (binary)
- {
- for (i = 0; i < nfields; i++)
- result->attDescs[i].format = 1;
- }
+ for (i = 0; i < nfields; i++)
+ result->attDescs[i].format = 1; }
- tup = conn->curTuple; /* Get the null-value bitmap */ nbytes = (nfields + BITS_PER_BYTE - 1) /
BITS_PER_BYTE;
@@ -757,7 +760,7 @@ getAnotherTuple(PGconn *conn, bool binary) { bitmap = (char *) malloc(nbytes); if
(!bitmap)
- goto outOfMemory;
+ goto rowProcessError; } if (pqGetnchar(bitmap, nbytes, conn))
@@ -771,34 +774,29 @@ getAnotherTuple(PGconn *conn, bool binary) for (i = 0; i < nfields; i++) { if
(!(bmap& 0200))
- {
- /* if the field value is absent, make it a null string */
- tup[i].value = result->null_field;
- tup[i].len = NULL_LEN;
- }
+ vlen = NULL_LEN;
+ else if (pqGetInt(&vlen, 4, conn))
+ goto EOFexit; else {
- /* get the value length (the first four bytes are for length) */
- if (pqGetInt(&vlen, 4, conn))
- goto EOFexit; if (!binary) vlen = vlen - 4; if (vlen < 0)
vlen = 0;
- if (tup[i].value == NULL)
- {
- tup[i].value = (char *) pqResultAlloc(result, vlen + 1, binary);
- if (tup[i].value == NULL)
- goto outOfMemory;
- }
- tup[i].len = vlen;
- /* read in the value */
- if (vlen > 0)
- if (pqGetnchar((char *) (tup[i].value), vlen, conn))
- goto EOFexit;
- /* we have to terminate this ourselves */
- tup[i].value[vlen] = '\0'; }
+
+ /*
+ * rowbuf[i].value always points to the next address of the
+ * length field even if the value is NULL, to allow safe
+ * size estimates and data copy.
+ */
+ rowbuf[i].value = conn->inBuffer + conn->inCursor;
+ rowbuf[i].len = vlen;
+
+ /* Skip the value */
+ if (vlen > 0 && pqSkipnchar(vlen, conn))
+ goto EOFexit;
+ /* advance the bitmap stuff */ bitcnt++; if (bitcnt == BITS_PER_BYTE)
@@ -811,33 +809,56 @@ getAnotherTuple(PGconn *conn, bool binary) bmap <<= 1; }
- /* Success! Store the completed tuple in the result */
- if (!pqAddTuple(result, tup))
- goto outOfMemory;
- /* and reset for a new message */
- conn->curTuple = NULL;
- if (bitmap != std_bitmap) free(bitmap);
- return 0;
+ bitmap = NULL;
+
+ /* tag the row as parsed */
+ conn->inStart = conn->inCursor;
+
+ /* Pass the completed row values to rowProcessor */
+ rp= conn->rowProcessor(result, conn->rowProcessorParam, rowbuf);
+ if (rp == 1)
+ return 0;
+ else if (rp == 2 && pqIsnonblocking(conn))
+ /* processor requested early exit */
+ return EOF;
+ else if (rp != 0)
+ PQsetRowProcessorErrMsg(result, libpq_gettext("invalid return value from row processor\n"));
+
+rowProcessError:
-outOfMemory: /* Replace partially constructed result with an error result */
- /*
- * we do NOT use pqSaveErrorResult() here, because of the likelihood that
- * there's not enough memory to concatenate messages...
- */
- pqClearAsyncResult(conn);
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("out of memory for query result\n"));
+ if (result->rowProcessorErrMsg)
+ {
+ printfPQExpBuffer(&conn->errorMessage, "%s", result->rowProcessorErrMsg);
+ pqSaveErrorResult(conn);
+ }
+ else
+ {
+ /*
+ * we do NOT use pqSaveErrorResult() here, because of the likelihood that
+ * there's not enough memory to concatenate messages...
+ */
+ pqClearAsyncResult(conn);
+ resetPQExpBuffer(&conn->errorMessage);
- /*
- * XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
- * do to recover...
- */
- conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
+ /*
+ * If error message is passed from RowProcessor, set it into
+ * PGconn, assume out of memory if not.
+ */
+ appendPQExpBufferStr(&conn->errorMessage,
+ libpq_gettext("out of memory for query result\n"));
+
+ /*
+ * XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
+ * do to recover...
+ */
+ conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
+ } conn->asyncStatus = PGASYNC_READY;
+ /* Discard the failed message --- good idea? */ conn->inStart = conn->inEnd;
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 892dcbc..0260ba6 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -327,6 +327,9 @@ pqParseInput3(PGconn *conn) /* Read another tuple of a normal query response
*/ if (getAnotherTuple(conn, msgLength)) return;
+
+ /* getAnotherTuple() moves inStart itself */
+ continue; } else if (conn->result != NULL &&
conn->result->resultStatus == PGRES_FATAL_ERROR)
@@ -613,33 +616,22 @@ failure:/* * parseInput subroutine to read a 'D' (row data) message.
- * We add another tuple to the existing PGresult structure.
+ * It fills rowbuf with column pointers and then calls row processor. * Returns: 0 if completed message, EOF if error
ornot enough data yet. * * Note that if we run out of data, we have to suspend and reprocess
- * the message after more data is received. We keep a partially constructed
- * tuple in conn->curTuple, and avoid reallocating already-allocated storage.
+ * the message after more data is received. */static intgetAnotherTuple(PGconn *conn, int msgLength){ PGresult
*result= conn->result; int nfields = result->numAttributes;
- PGresAttValue *tup;
+ PGrowValue *rowbuf; int tupnfields; /* # fields from tuple */ int vlen;
/* length of the current field value */ int i;
-
- /* Allocate tuple space if first time for this data message */
- if (conn->curTuple == NULL)
- {
- conn->curTuple = (PGresAttValue *)
- pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
- if (conn->curTuple == NULL)
- goto outOfMemory;
- MemSet(conn->curTuple, 0, nfields * sizeof(PGresAttValue));
- }
- tup = conn->curTuple;
+ int rp; /* Get the field count and make sure it's what we expect */ if (pqGetInt(&tupnfields, 2,
conn))
@@ -652,52 +644,88 @@ getAnotherTuple(PGconn *conn, int msgLength) libpq_gettext("unexpected field
countin \"D\" message\n")); pqSaveErrorResult(conn); /* Discard the failed message by pretending we read
it*/
- conn->inCursor = conn->inStart + 5 + msgLength;
+ conn->inStart += 5 + msgLength; return 0; }
+ /* resize row buffer if needed */
+ rowbuf = conn->rowBuf;
+ if (nfields > conn->rowBufLen)
+ {
+ rowbuf = realloc(conn->rowBuf, nfields * sizeof(PGrowValue));
+ if (!rowbuf)
+ {
+ goto outOfMemory1;
+ }
+ conn->rowBuf = rowbuf;
+ conn->rowBufLen = nfields;
+ }
+ /* Scan the fields */ for (i = 0; i < nfields; i++) { /* get the value length */ if
(pqGetInt(&vlen,4, conn))
- return EOF;
+ goto protocolError; if (vlen == -1)
- {
- /* null field */
- tup[i].value = result->null_field;
- tup[i].len = NULL_LEN;
- continue;
- }
- if (vlen < 0)
+ vlen = NULL_LEN;
+ else if (vlen < 0) vlen = 0;
- if (tup[i].value == NULL)
- {
- bool isbinary = (result->attDescs[i].format != 0);
- tup[i].value = (char *) pqResultAlloc(result, vlen + 1, isbinary);
- if (tup[i].value == NULL)
- goto outOfMemory;
- }
- tup[i].len = vlen;
- /* read in the value */
- if (vlen > 0)
- if (pqGetnchar((char *) (tup[i].value), vlen, conn))
- return EOF;
- /* we have to terminate this ourselves */
- tup[i].value[vlen] = '\0';
+ /*
+ * rowbuf[i].value always points to the next address of the
+ * length field even if the value is NULL, to allow safe
+ * size estimates and data copy.
+ */
+ rowbuf[i].value = conn->inBuffer + conn->inCursor;
+ rowbuf[i].len = vlen;
+
+ /* Skip to the next length field */
+ if (vlen > 0 && pqSkipnchar(vlen, conn))
+ goto protocolError; }
- /* Success! Store the completed tuple in the result */
- if (!pqAddTuple(result, tup))
- goto outOfMemory;
- /* and reset for a new message */
- conn->curTuple = NULL;
+ /* tag the row as parsed, check if correctly */
+ conn->inStart += 5 + msgLength;
+ if (conn->inCursor != conn->inStart)
+ goto protocolError;
+ /* Pass the completed row values to rowProcessor */
+ rp = conn->rowProcessor(result, conn->rowProcessorParam, rowbuf);
+ if (rp == 1)
+ {
+ /* everything is good */
+ return 0;
+ }
+ if (rp == 2 && pqIsnonblocking(conn))
+ {
+ /* processor requested early exit */
+ return EOF;
+ }
+
+ /* there was some problem */
+ if (rp == 0)
+ {
+ if (result->rowProcessorErrMsg == NULL)
+ goto outOfMemory2;
+
+ /* use supplied error message */
+ printfPQExpBuffer(&conn->errorMessage, "%s", result->rowProcessorErrMsg);
+ }
+ else
+ {
+ /* row processor messed up */
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("invalid return value from row processor\n"));
+ }
+ pqSaveErrorResult(conn); return 0;
-outOfMemory:
+outOfMemory1:
+ /* Discard the failed message by pretending we read it */
+ conn->inStart += 5 + msgLength;
+outOfMemory2: /* * Replace partially constructed result with an error result. First * discard the old
resultto try to win back some memory.
@@ -706,9 +734,14 @@ outOfMemory: printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of
memoryfor query result\n")); pqSaveErrorResult(conn);
+ return 0;
+protocolError:
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("invalid row contents\n"));
+ pqSaveErrorResult(conn); /* Discard the failed message by pretending we read it */
- conn->inCursor = conn->inStart + 5 + msgLength;
+ conn->inStart += 5 + msgLength; return 0;}
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index ef26ab9..2d913c4 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -149,6 +149,17 @@ typedef struct pgNotify struct pgNotify *next; /* list link */} PGnotify;
+/* PGrowValue points a column value of in network buffer.
+ * Value is a string without null termination and length len.
+ * NULL is represented as len < 0, value points then to place
+ * where value would have been.
+ */
+typedef struct pgRowValue
+{
+ int len; /* length in bytes of the value */
+ char *value; /* actual value, without null termination */
+} PGrowValue;
+/* Function types for notice-handling callbacks */typedef void (*PQnoticeReceiver) (void *arg, const PGresult
*res);typedefvoid (*PQnoticeProcessor) (void *arg, const char *message);
@@ -367,6 +378,8 @@ extern PGresult *PQexecPrepared(PGconn *conn, const int *paramFormats,
intresultFormat);
+extern PGresult *PQskipRemainingResults(PGconn *conn);
+/* Interface for multiple-result or asynchronous queries */extern int PQsendQuery(PGconn *conn, const char
*query);externint PQsendQueryParams(PGconn *conn,
@@ -416,6 +429,37 @@ extern PGPing PQping(const char *conninfo);extern PGPing PQpingParams(const char *const *
keywords, const char *const * values, int expand_dbname);
+/*
+ * Typedef for alternative row processor.
+ *
+ * Columns array will contain PQnfields() entries, each one
+ * pointing to particular column data in network buffer.
+ * This function is supposed to copy data out from there
+ * and store somewhere. NULL is signified with len<0.
+ *
+ * This function must return 1 for success and must return 0 for
+ * failure and may set error message by PQsetRowProcessorErrMsg. It
+ * is assumed by caller as out of memory when the error message is not
+ * set on failure. This function is assumed not to throw any
+ * exception.
+ */
+typedef int (*PQrowProcessor)(PGresult *res, void *param,
+ PGrowValue *columns);
+
+/*
+ * Set alternative row data processor for PGconn.
+ *
+ * By registering this function, pg_result disables its own result
+ * store and calls it for rows one by one.
+ *
+ * func is row processor function. See the typedef RowProcessor.
+ *
+ * rowProcessorParam is the contextual variable that passed to
+ * RowProcessor.
+ */
+extern void PQsetRowProcessor(PGconn *conn, PQrowProcessor func,
+ void *rowProcessorParam);
+/* Force the write buffer to be written (or at least try) */extern int PQflush(PGconn *conn);
@@ -454,6 +498,7 @@ extern char *PQcmdTuples(PGresult *res);extern char *PQgetvalue(const PGresult *res, int tup_num,
intfield_num);extern int PQgetlength(const PGresult *res, int tup_num, int field_num);extern int
PQgetisnull(constPGresult *res, int tup_num, int field_num);
+extern void PQsetRowProcessorErrMsg(PGresult *res, char *msg);extern int PQnparams(const PGresult *res);extern
Oid PQparamtype(const PGresult *res, int param_num);
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 987311e..1fc5aab 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -209,6 +209,9 @@ struct pg_result PGresult_data *curBlock; /* most recently allocated block */ int
curOffset; /* start offset of free space in block */ int spaceLeft; /* number of free
bytesremaining in block */
+
+ /* temp etorage for message from row processor callback */
+ char *rowProcessorErrMsg;};/* PGAsyncStatusType defines the state of the query-execution state machine */
@@ -398,7 +401,6 @@ struct pg_conn /* Status for asynchronous result construction */ PGresult *result;
/* result being constructed */
- PGresAttValue *curTuple; /* tuple currently being read */#ifdef USE_SSL bool allow_ssl_try; /*
Allowedto try SSL negotiation */
@@ -443,6 +445,14 @@ struct pg_conn /* Buffer for receiving various parts of messages */ PQExpBufferData
workBuffer;/* expansible string */
+
+ /*
+ * Read column data from network buffer.
+ */
+ PQrowProcessor rowProcessor;/* Function pointer */
+ void *rowProcessorParam; /* Contextual parameter for rowProcessor */
+ PGrowValue *rowBuf; /* Buffer for passing values to rowProcessor */
+ int rowBufLen; /* Number of columns allocated in rowBuf */};/* PGcancel stores all data necessary
tocancel a connection. A copy of this
@@ -560,6 +570,7 @@ extern int pqGets(PQExpBuffer buf, PGconn *conn);extern int pqGets_append(PQExpBuffer buf,
PGconn*conn);extern int pqPuts(const char *s, PGconn *conn);extern int pqGetnchar(char *s, size_t len, PGconn
*conn);
+extern int pqSkipnchar(size_t len, PGconn *conn);extern int pqPutnchar(const char *s, size_t len, PGconn
*conn);externint pqGetInt(int *result, size_t bytes, PGconn *conn);extern int pqPutInt(int value, size_t bytes,
PGconn*conn);
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 72c9384..9cb6d65 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -7233,6 +7233,274 @@ int PQisthreadsafe(); </sect1>
+ <sect1 id="libpq-altrowprocessor">
+ <title>Alternative row processor</title>
+
+ <indexterm zone="libpq-altrowprocessor">
+ <primary>PGresult</primary>
+ <secondary>PGconn</secondary>
+ </indexterm>
+
+ <para>
+ As the standard usage, rows are stored into <type>PQresult</type>
+ until full resultset is received. Then such completely-filled
+ <type>PQresult</type> is passed to user. This behaviour can be
+ changed by registering alternative row processor function,
+ that will see each row data as soon as it is received
+ from network. It has the option of processing the data
+ immediately, or storing it into custom container.
+ </para>
+
+ <para>
+ Note - as row processor sees rows as they arrive, it cannot know
+ whether the SQL statement actually finishes successfully on server
+ or not. So some care must be taken to get proper
+ transactionality.
+ </para>
+
+ <variablelist>
+ <varlistentry id="libpq-pqsetrowprocessor">
+ <term>
+ <function>PQsetRowProcessor</function>
+ <indexterm>
+ <primary>PQsetRowProcessor</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ Sets a callback function to process each row.
+<synopsis>
+void PQsetRowProcessor(PGconn *conn, PQrowProcessor func, void *param);
+</synopsis>
+ </para>
+
+ <para>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>conn</parameter></term>
+ <listitem>
+ <para>
+ The connection object to set the row processor function.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>func</parameter></term>
+ <listitem>
+ <para>
+ Storage handler function to set. NULL means to use the
+ default processor.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>param</parameter></term>
+ <listitem>
+ <para>
+ A pointer to contextual parameter passed
+ to <parameter>func</parameter>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <variablelist>
+ <varlistentry id="libpq-pqrowprocessor">
+ <term>
+ <type>PQrowProcessor</type>
+ <indexterm>
+ <primary>PQrowProcessor</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ The type for the row processor callback function.
+<synopsis>
+int (*PQrowProcessor)(PGresult *res, void *param, PGrowValue *columns);
+
+typedef struct
+{
+ int len; /* length in bytes of the value, -1 if NULL */
+ char *value; /* actual value, without null termination */
+} PGrowValue;
+</synopsis>
+ </para>
+
+ <para>
+ The <parameter>columns</parameter> array will have PQnfields()
+ elements, each one pointing to column value in network buffer.
+ The <parameter>len</parameter> field will contain number of
+ bytes in value. If the field value is NULL then
+ <parameter>len</parameter> will be -1 and value will point
+ to position where the value would have been in buffer.
+ This allows estimating row size by pointer arithmetic.
+ </para>
+
+ <para>
+ This function must process or copy row values away from network
+ buffer before it returns, as next row might overwrite them.
+ </para>
+
+ <para>
+ This function must return 1 for success, and 0 for failure.
+ On failure this function should set the error message
+ with <function>PGsetRowProcessorErrMsg</function> if the cause
+ is other than out of memory.
+ When non-blocking API is in use, it can also return 2
+ for early exit from <function>PQisBusy</function> function.
+ The supplied <parameter>res</parameter> and <parameter>columns</parameter>
+ values will stay valid so row can be processed outside of callback.
+ Caller is resposible for tracking whether the <parameter>PQisBusy</parameter>
+ returned early from callback or for other reasons.
+ Usually this should happen via setting cached values to NULL
+ before calling <function>PQisBusy</function>.
+ </para>
+
+ <para>
+ The function is allowed to exit via exception (setjmp/longjmp).
+ The connection and row are guaranteed to be in valid state.
+ The connection can later be closed via <function>PQfinish</function>.
+ Processing can also be continued without closing the connection,
+ call <function>getResult</function> on syncronous mode,
+ <function>PQisBusy</function> on asynchronous connection. Then
+ processing will continue with new row, previous row that got
+ exception will be skipped. Or you can discard all remaing rows
+ by calling <function>PQskipRemainingResults</function> without
+ closing connection.
+ </para>
+
+ <variablelist>
+ <varlistentry>
+
+ <term><parameter>res</parameter></term>
+ <listitem>
+ <para>
+ A pointer to the <type>PGresult</type> object.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+
+ <term><parameter>param</parameter></term>
+ <listitem>
+ <para>
+ Extra parameter that was given to <function>PQsetRowProcessor</function>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+
+ <term><parameter>columns</parameter></term>
+ <listitem>
+ <para>
+ Column values of the row to process. Column values
+ are located in network buffer, the processor must
+ copy them out from there.
+ </para>
+ <para>
+ Column values are not null-terminated, so processor cannot
+ use C string functions on them directly.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <variablelist>
+ <varlistentry id="libpq-pqskipremaingresults">
+ <term>
+ <function>PQskipRemainigResults</function>
+ <indexterm>
+ <primary>PQskipRemainigResults</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Discard all the remaining row data
+ after <function>PQexec</function>
+ or <function>PQgetResult</function> exits by the exception raised
+ in <type>RowProcessor</type> without closing connection.
+ </para>
+ <para>
+ Do not call this function when the functions above return normally.
+<synopsis>
+void PQskipRemainingResults(PGconn *conn)
+</synopsis>
+ </para>
+ <para>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>conn</parameter></term>
+ <listitem>
+ <para>
+ The connection object.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <variablelist>
+ <varlistentry id="libpq-pqsetrowprocessorerrmsg">
+ <term>
+ <function>PQsetRowProcessorErrMsg</function>
+ <indexterm>
+ <primary>PQsetRowProcessorErrMsg</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Set the message for the error occurred
+ in <type>PQrowProcessor</type>. If this message is not set, the
+ caller assumes the error to be out of memory.
+<synopsis>
+void PQsetRowProcessorErrMsg(PGresult *res, char *msg)
+</synopsis>
+ </para>
+ <para>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>res</parameter></term>
+ <listitem>
+ <para>
+ A pointer to the <type>PGresult</type> object
+ passed to <type>PQrowProcessor</type>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>msg</parameter></term>
+ <listitem>
+ <para>
+ Error message. This will be copied internally so there is
+ no need to care of the scope.
+ </para>
+ <para>
+ If <parameter>res</parameter> already has a message previously
+ set, it will be overwritten. Set NULL to cancel the the custom
+ message.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </sect1>
+
+ <sect1 id="libpq-build"> <title>Building <application>libpq</application> Programs</title>
diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 36a8e3e..b1c171a 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -63,11 +63,24 @@ typedef struct remoteConn bool newXactForCursor; /* Opened a transaction for a
cursor*/} remoteConn;
+typedef struct storeInfo
+{
+ Tuplestorestate *tuplestore;
+ int nattrs;
+ MemoryContext oldcontext;
+ AttInMetadata *attinmeta;
+ char** valbuf;
+ int *valbuflen;
+ char **cstrs;
+ bool error_occurred;
+ bool nummismatch;
+ ErrorData *edata;
+} storeInfo;
+/* * Internal declarations */static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async);
-static void materializeResult(FunctionCallInfo fcinfo, PGresult *res);static remoteConn *getConnectionByName(const
char*name);static HTAB *createConnHash(void);static void createNewConnection(const char *name, remoteConn *rconn);
@@ -90,6 +103,10 @@ static char *escape_param_str(const char *from);static void validate_pkattnums(Relation rel,
int2vector *pkattnums_arg, int32 pknumatts_arg, int **pkattnums, int *pknumatts);
+static void initStoreInfo(storeInfo *sinfo, FunctionCallInfo fcinfo);
+static void finishStoreInfo(storeInfo *sinfo);
+static int storeHandler(PGresult *res, void *param, PGrowValue *columns);
+/* Global */static remoteConn *pconn = NULL;
@@ -503,6 +520,7 @@ dblink_fetch(PG_FUNCTION_ARGS) char *curname = NULL; int howmany = 0;
bool fail = true; /* default to backward compatible */
+ storeInfo storeinfo; DBLINK_INIT;
@@ -559,15 +577,36 @@ dblink_fetch(PG_FUNCTION_ARGS) appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
/*
+ * Result is stored into storeinfo.tuplestore instead of
+ * res->result retuned by PQexec below
+ */
+ initStoreInfo(&storeinfo, fcinfo);
+ PQsetRowProcessor(conn, storeHandler, &storeinfo);
+
+ /* * Try to execute the query. Note that since libpq uses malloc, the * PGresult will be long-lived even
thoughwe are still in a short-lived * memory context. */ res = PQexec(conn, buf.data);
+ finishStoreInfo(&storeinfo);
+ if (!res || (PQresultStatus(res) != PGRES_COMMAND_OK && PQresultStatus(res) != PGRES_TUPLES_OK))
{
+ /* finishStoreInfo saves the fields referred to below. */
+ if (storeinfo.nummismatch)
+ {
+ /* This is only for backward compatibility */
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("remote query result rowtype does not match "
+ "the specified FROM clause rowtype")));
+ }
+ else if (storeinfo.edata)
+ ReThrowError(storeinfo.edata);
+ dblink_res_error(conname, res, "could not fetch from cursor", fail); return (Datum) 0; }
@@ -579,8 +618,8 @@ dblink_fetch(PG_FUNCTION_ARGS) (errcode(ERRCODE_INVALID_CURSOR_NAME),
errmsg("cursor \"%s\" does not exist", curname))); }
+ PQclear(res);
- materializeResult(fcinfo, res); return (Datum) 0;}
@@ -640,6 +679,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async) remoteConn *rconn = NULL; bool
fail = true; /* default to backward compatible */ bool freeconn = false;
+ storeInfo storeinfo; /* check to see if caller supports us returning a tuplestore */ if (rsinfo == NULL ||
!IsA(rsinfo,ReturnSetInfo))
@@ -715,164 +755,249 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async) rsinfo->setResult = NULL;
rsinfo->setDesc= NULL;
+
+ /*
+ * Result is stored into storeinfo.tuplestore instead of
+ * res->result retuned by PQexec/PQgetResult below
+ */
+ initStoreInfo(&storeinfo, fcinfo);
+ PQsetRowProcessor(conn, storeHandler, &storeinfo);
+ /* synchronous query, or async result retrieval */
- if (!is_async)
- res = PQexec(conn, sql);
- else
+ PG_TRY(); {
- res = PQgetResult(conn);
- /* NULL means we're all done with the async results */
- if (!res)
- return (Datum) 0;
+ if (!is_async)
+ res = PQexec(conn, sql);
+ else
+ res = PQgetResult(conn);
+ }
+ PG_CATCH();
+ {
+ /* Skip remaining results when storeHandler raises exception. */
+ PQskipRemainingResults(conn);
+ storeinfo.error_occurred = TRUE; }
+ PG_END_TRY();
- /* if needed, close the connection to the database and cleanup */
- if (freeconn)
- PQfinish(conn);
+ finishStoreInfo(&storeinfo);
- if (!res ||
- (PQresultStatus(res) != PGRES_COMMAND_OK &&
- PQresultStatus(res) != PGRES_TUPLES_OK))
+ /* NULL res from async get means we're all done with the results */
+ if (res || !is_async) {
- dblink_res_error(conname, res, "could not execute query", fail);
- return (Datum) 0;
+ if (freeconn)
+ PQfinish(conn);
+
+ if (!res ||
+ (PQresultStatus(res) != PGRES_COMMAND_OK &&
+ PQresultStatus(res) != PGRES_TUPLES_OK))
+ {
+ /* finishStoreInfo saves the fields referred to below. */
+ if (storeinfo.nummismatch)
+ {
+ /* This is only for backward compatibility */
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("remote query result rowtype does not match "
+ "the specified FROM clause rowtype")));
+ }
+ else if (storeinfo.edata)
+ ReThrowError(storeinfo.edata);
+
+ dblink_res_error(conname, res, "could not execute query", fail);
+ return (Datum) 0;
+ } }
+ PQclear(res);
- materializeResult(fcinfo, res); return (Datum) 0;}
-/*
- * Materialize the PGresult to return them as the function result.
- * The res will be released in this function.
- */static void
-materializeResult(FunctionCallInfo fcinfo, PGresult *res)
+initStoreInfo(storeInfo *sinfo, FunctionCallInfo fcinfo){ ReturnSetInfo *rsinfo = (ReturnSetInfo *)
fcinfo->resultinfo;
+ TupleDesc tupdesc;
+ int i;
- Assert(rsinfo->returnMode == SFRM_Materialize);
+ switch (get_call_result_type(fcinfo, NULL, &tupdesc))
+ {
+ case TYPEFUNC_COMPOSITE:
+ /* success */
+ break;
+ case TYPEFUNC_RECORD:
+ /* failed to determine actual type of RECORD */
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("function returning record called in context "
+ "that cannot accept type record")));
+ break;
+ default:
+ /* result type isn't composite */
+ elog(ERROR, "return type must be a row type");
+ break;
+ }
- PG_TRY();
+ sinfo->oldcontext = MemoryContextSwitchTo(
+ rsinfo->econtext->ecxt_per_query_memory);
+
+ /* make sure we have a persistent copy of the tupdesc */
+ tupdesc = CreateTupleDescCopy(tupdesc);
+
+ sinfo->error_occurred = FALSE;
+ sinfo->nummismatch = FALSE;
+ sinfo->attinmeta = TupleDescGetAttInMetadata(tupdesc);
+ sinfo->edata = NULL;
+ sinfo->nattrs = tupdesc->natts;
+ sinfo->tuplestore = tuplestore_begin_heap(true, false, work_mem);
+ sinfo->valbuf = NULL;
+ sinfo->valbuflen = NULL;
+
+ /* Preallocate memory of same size with c string array for values. */
+ sinfo->valbuf = (char **)malloc(sinfo->nattrs * sizeof(char*));
+ if (sinfo->valbuf)
+ sinfo->valbuflen = (int *)malloc(sinfo->nattrs * sizeof(int));
+ if (sinfo->valbuflen)
+ sinfo->cstrs = (char **)malloc(sinfo->nattrs * sizeof(char*));
+
+ if (sinfo->cstrs == NULL) {
- TupleDesc tupdesc;
- bool is_sql_cmd = false;
- int ntuples;
- int nfields;
+ if (sinfo->valbuf)
+ free(sinfo->valbuf);
+ if (sinfo->valbuflen)
+ free(sinfo->valbuflen);
- if (PQresultStatus(res) == PGRES_COMMAND_OK)
- {
- is_sql_cmd = true;
+ ereport(ERROR,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("out of memory")));
+ }
- /*
- * need a tuple descriptor representing one TEXT column to return
- * the command status string as our result tuple
- */
- tupdesc = CreateTemplateTupleDesc(1, false);
- TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
- TEXTOID, -1, 0);
- ntuples = 1;
- nfields = 1;
- }
- else
- {
- Assert(PQresultStatus(res) == PGRES_TUPLES_OK);
+ for (i = 0 ; i < sinfo->nattrs ; i++)
+ {
+ sinfo->valbuf[i] = NULL;
+ sinfo->valbuflen[i] = -1;
+ }
- is_sql_cmd = false;
+ rsinfo->setResult = sinfo->tuplestore;
+ rsinfo->setDesc = tupdesc;
+}
- /* get a tuple descriptor for our result type */
- switch (get_call_result_type(fcinfo, NULL, &tupdesc))
- {
- case TYPEFUNC_COMPOSITE:
- /* success */
- break;
- case TYPEFUNC_RECORD:
- /* failed to determine actual type of RECORD */
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("function returning record called in context "
- "that cannot accept type record")));
- break;
- default:
- /* result type isn't composite */
- elog(ERROR, "return type must be a row type");
- break;
- }
+static void
+finishStoreInfo(storeInfo *sinfo)
+{
+ int i;
- /* make sure we have a persistent copy of the tupdesc */
- tupdesc = CreateTupleDescCopy(tupdesc);
- ntuples = PQntuples(res);
- nfields = PQnfields(res);
+ if (sinfo->valbuf)
+ {
+ for (i = 0 ; i < sinfo->nattrs ; i++)
+ {
+ if (sinfo->valbuf[i])
+ free(sinfo->valbuf[i]); }
+ free(sinfo->valbuf);
+ sinfo->valbuf = NULL;
+ }
- /*
- * check result and tuple descriptor have the same number of columns
- */
- if (nfields != tupdesc->natts)
- ereport(ERROR,
- (errcode(ERRCODE_DATATYPE_MISMATCH),
- errmsg("remote query result rowtype does not match "
- "the specified FROM clause rowtype")));
+ if (sinfo->valbuflen)
+ {
+ free(sinfo->valbuflen);
+ sinfo->valbuflen = NULL;
+ }
- if (ntuples > 0)
- {
- AttInMetadata *attinmeta;
- Tuplestorestate *tupstore;
- MemoryContext oldcontext;
- int row;
- char **values;
-
- attinmeta = TupleDescGetAttInMetadata(tupdesc);
-
- oldcontext = MemoryContextSwitchTo(
- rsinfo->econtext->ecxt_per_query_memory);
- tupstore = tuplestore_begin_heap(true, false, work_mem);
- rsinfo->setResult = tupstore;
- rsinfo->setDesc = tupdesc;
- MemoryContextSwitchTo(oldcontext);
+ if (sinfo->cstrs)
+ {
+ free(sinfo->cstrs);
+ sinfo->cstrs = NULL;
+ }
- values = (char **) palloc(nfields * sizeof(char *));
+ MemoryContextSwitchTo(sinfo->oldcontext);
+}
- /* put all tuples into the tuplestore */
- for (row = 0; row < ntuples; row++)
- {
- HeapTuple tuple;
+static int
+storeHandler(PGresult *res, void *param, PGrowValue *columns)
+{
+ storeInfo *sinfo = (storeInfo *)param;
+ HeapTuple tuple;
+ int fields = PQnfields(res);
+ int i;
+ char **cstrs = sinfo->cstrs;
- if (!is_sql_cmd)
- {
- int i;
+ if (sinfo->error_occurred)
+ return FALSE;
- for (i = 0; i < nfields; i++)
- {
- if (PQgetisnull(res, row, i))
- values[i] = NULL;
- else
- values[i] = PQgetvalue(res, row, i);
- }
- }
- else
- {
- values[0] = PQcmdStatus(res);
- }
+ if (sinfo->nattrs != fields)
+ {
+ sinfo->error_occurred = TRUE;
+ sinfo->nummismatch = TRUE;
+ finishStoreInfo(sinfo);
+
+ /* This error will be processed in
+ * dblink_record_internal(). So do not set error message
+ * here. */
+ return FALSE;
+ }
+
+ /*
+ * value input functions assumes that the input string is
+ * terminated by zero. We should make the values to be so.
+ */
+ for(i = 0 ; i < fields ; i++)
+ {
+ int len = columns[i].len;
+ if (len < 0)
+ cstrs[i] = NULL;
+ else
+ {
+ char *tmp = sinfo->valbuf[i];
+ int tmplen = sinfo->valbuflen[i];
- /* build the tuple and put it into the tuplestore. */
- tuple = BuildTupleFromCStrings(attinmeta, values);
- tuplestore_puttuple(tupstore, tuple);
+ /*
+ * Divide calls to malloc and realloc so that things will
+ * go fine even on the systems of which realloc() does not
+ * accept NULL as old memory block.
+ *
+ * Also try to (re)allocate in bigger steps to
+ * avoid flood of allocations on weird data.
+ */
+ if (tmp == NULL)
+ {
+ tmplen = len + 1;
+ if (tmplen < 64)
+ tmplen = 64;
+ tmp = (char *)malloc(tmplen);
+ }
+ else if (tmplen < len + 1)
+ {
+ if (len + 1 > tmplen * 2)
+ tmplen = len + 1;
+ else
+ tmplen = tmplen * 2;
+ tmp = (char *)realloc(tmp, tmplen); }
- /* clean up and return the tuplestore */
- tuplestore_donestoring(tupstore);
- }
+ /*
+ * sinfo->valbuf[n] will be freed in finishStoreInfo()
+ * when realloc returns NULL.
+ */
+ if (tmp == NULL)
+ return FALSE;
- PQclear(res);
- }
- PG_CATCH();
- {
- /* be sure to release the libpq result */
- PQclear(res);
- PG_RE_THROW();
+ sinfo->valbuf[i] = tmp;
+ sinfo->valbuflen[i] = tmplen;
+
+ cstrs[i] = sinfo->valbuf[i];
+ memcpy(cstrs[i], columns[i].value, len);
+ cstrs[i][len] = '\0';
+ } }
- PG_END_TRY();
+
+ /*
+ * These functions may throw exception. It will be caught in
+ * dblink_record_internal()
+ */
+ tuple = BuildTupleFromCStrings(sinfo->attinmeta, cstrs);
+ tuplestore_puttuple(sinfo->tuplestore, tuple);
+
+ return TRUE;}/*
diff --git b/doc/src/sgml/libpq.sgml a/doc/src/sgml/libpq.sgml
index de95ea8..9cb6d65 100644
--- b/doc/src/sgml/libpq.sgml
+++ a/doc/src/sgml/libpq.sgml
@@ -7352,6 +7352,14 @@ typedef struct On failure this function should set the error message with
<function>PGsetRowProcessorErrMsg</function>if the cause is other than out of memory.
+ When non-blocking API is in use, it can also return 2
+ for early exit from <function>PQisBusy</function> function.
+ The supplied <parameter>res</parameter> and <parameter>columns</parameter>
+ values will stay valid so row can be processed outside of callback.
+ Caller is resposible for tracking whether the <parameter>PQisBusy</parameter>
+ returned early from callback or for other reasons.
+ Usually this should happen via setting cached values to NULL
+ before calling <function>PQisBusy</function>. </para> <para>
diff --git b/src/interfaces/libpq/fe-protocol2.c a/src/interfaces/libpq/fe-protocol2.c
index 7498580..ae4d7b0 100644
--- b/src/interfaces/libpq/fe-protocol2.c
+++ a/src/interfaces/libpq/fe-protocol2.c
@@ -820,6 +820,9 @@ getAnotherTuple(PGconn *conn, bool binary) rp= conn->rowProcessor(result,
conn->rowProcessorParam,rowbuf); if (rp == 1) return 0;
+ else if (rp == 2 && pqIsnonblocking(conn))
+ /* processor requested early exit */
+ return EOF; else if (rp != 0) PQsetRowProcessorErrMsg(result, libpq_gettext("invalid return value
fromrow processor\n"));
diff --git b/src/interfaces/libpq/fe-protocol3.c a/src/interfaces/libpq/fe-protocol3.c
index a67e3ac..0260ba6 100644
--- b/src/interfaces/libpq/fe-protocol3.c
+++ a/src/interfaces/libpq/fe-protocol3.c
@@ -697,6 +697,11 @@ getAnotherTuple(PGconn *conn, int msgLength) /* everything is good */ return 0;
}
+ if (rp == 2 && pqIsnonblocking(conn))
+ {
+ /* processor requested early exit */
+ return EOF;
+ } /* there was some problem */ if (rp == 0)
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