Re: PQexecParams performance
От | Tom Lane |
---|---|
Тема | Re: PQexecParams performance |
Дата | |
Msg-id | 8715.1134498368@sss.pgh.pa.us обсуждение исходный текст |
Ответ на | PQexecParams performance ("Harry Rossignol" <harrywr2@comcast.net>) |
Список | pgsql-bugs |
"Harry Rossignol" <harrywr2@comcast.net> writes: > This statement via SQLexec executes in the blink of an eye > DECLARE XNKPE BINARY CURSOR for SELECT wtsnzblob FROM "NZRECS" WHERE > wtsevent = '05002' AND wtspaymeth = '$' AND wtspayno = '' AND ( wtstrxtm >> '19691231 160000' OR (wtstrxtm = '19691231 160000' AND wtscpu > '0') > OR (wtstrxtm = '19691231 160000' AND wtscpu = '0' AND wtsuser > '0')) > ORDER BY wtstrxtm,wtscpu,wtsuser LIMIT 64 > This statement via SQLExecParams can be measured in 10's of seconds, and > takes an amount of time that is linear to the size of the database, even > though the number of records that equal parameter 1, wtsevent is static. > DECLARE XNKPE BINARY CURSOR for SELECT wtsnzblob FROM "NZRECS" WHERE > wtsevent = $1 AND wtspaymeth = $2 AND wtspayno = $3 AND ( wtstrxtm > $4 > OR (wtstrxtm = $4 AND wtscpu > $5) OR (wtstrxtm = $4 AND wtscpu = $5 AND > wtsuser > $6)) ORDER BY wtstrxtm,wtscpu,wtsuser LIMIT 64 Could we see the EXPLAIN ANALYZE for both cases? Also the table schema (particularly the available indexes). (Note: easiest way to get EXPLAIN ANALYZE by hand for a parameterized query is to PREPARE it and then issue EXPLAIN ANALYZE EXECUTE.) regards, tom lane
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