pgsql: Fix handling of volatile expressions in COPY FROM ... WHERE

Fix handling of volatile expressions in COPY FROM ... WHERE

The checking for calls to volatile functions in the COPY FROM ... WHERE
expression was treating all WHERE clauses as if containing such calls.
While that does not produce incorrect results, this disables batching
which may result in significant performance regression.

Discussion:
https://www.postgresql.org/message-id/flat/CALAY4q_DdpWDuB5-Zyi-oTtO2uSk8pmy+dupiRe3AvAc++1imA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4a8283d0ec5a6781b9e0d4ba16b44da8a0856d02

Modified Files
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src/backend/commands/copy.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)