there is already a transaction in progress ?

It probably shows I am new to postgreSQL. I recently started running this
instead of DB2, and am converting the applications I already wrote. These
use ecpg.

The problem I have concerns transactions. I have an application (the first
one I am converting) that inserts a lot of stuff into three tables. (It is
normalizing a .tsv file from a spreadsheet.) The program is in C++.

The structure of the program is, I think,   ...   dbBase stock_database(STOCK_DB); // Constructor opens connection
...  EXEC SQL SET AUTOCOMMIT = off; // Just in case.   ...   while(input.next()) {       // Process each line of the
file.  ...       cerr << "BEGIN WORK" << endl;EXEC SQL BEGIN WORK;   ...       [insert stuff]       [if error] {
      cerr << "ROLLBACK WORK" << endl;    EXEC SQL ROLLBACK WORK;    continue;        }   ...       [if no error] {
         cerr << "COMMIT WORK" << endl;        EXEC SQL COMMIT WORK;       }   }   ...   [dbBase destructor closes the
connectionto the postmaster]
 

I have shortened the program to run three iterations instead of the normal
30,000 or so, and I get this output:

BEGIN WORK
COMMIT WORK
BEGIN WORK
COMMIT WORK
BEGIN WORK
COMMIT WORK

and it inserts the three items; I can see them with psql.

The trouble is that the /src/dbms/dataB/pgsql/pg_xlog says this:

2007-08-18 07:26:28 EDT LOG:  autovacuum: processing database "stock"
2007-08-18 07:27:20 EDT WARNING:  there is already a transaction in progress
2007-08-18 07:27:20 EDT WARNING:  there is already a transaction in progress
2007-08-18 07:27:20 EDT WARNING:  there is already a transaction in progress
2007-08-18 07:28:20 EDT LOG:  autovacuum: processing database "stock"

The autovacuum is just the regular stuff. I put the timestamps into the
logfiles because it was otherwise too difficult to see what was what.

I restarted the postgres system (/etc/rc.d/init.d/postgres restart) in case
some leftover transaction was lying around -- though I am not sure this is
enough.

I cannot believe this is normal. Do incomplete transactions persist around a
shutdown and restart of postmaster? And if so, how do I clear the lost
transaction?

BTW, when I test this, I DELETE FROM all the tables, and reset all the
sequences with this kind of thing:

ALTER SEQUENCE company_company_id_seq   RESTART WITH 10000;

before running the test program.

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