[pgpool-committers: 9579] pgpool: Fix Describe() so that it does not abort with portal created by

[Tatsuo Ishii]

Fix Describe() so that it does not abort with portal created by DECLARE.

When DECLARE foo CURSOR FOR is executed, a portal named "foo" is
automatically created by PostgreSQL. As the portal is not managed by
Pgpool-II, "Describe foo" message failed with "unable to execute
Describe. unable to get the bind message" error.

To fix this, make Describe() creates a dummy write query context so
that the describe message is sent to primary (streaming replication
mode) or all nodes (replication/snapshot isolation mode).

Problem analysis by Heather Lapointe.
Discussion: https://www.pgpool.net/pipermail/pgpool-general/2023-September/008995.html

Branch
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V4_1_STABLE

Details
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https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=c051ab93da32c1444802e9d0c19268f30b458a2c

Modified Files
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src/protocol/pool_proto_modules.c | 48 ++++++++++++++++++++++++++++++++++-----
1 file changed, 42 insertions(+), 6 deletions(-)