postgres_fdw: Fix corner cases in transaction mode propagation.
This commit addresses the following issues in commit de28140de:
* When the local transaction was DEFERRABLE, begin_remote_xact() started
a remote transaction in the same mode without checking the remote
server version. Since DEFERRABLE is supported only in v9.1 and later,
this would cause a syntax error on older remote servers. Fix this by
propagating the mode only to remote servers that support it.
* pgfdw_xact_callback() committed remote transactions without
synchronizing the read-only mode. If the local transaction had become
READ ONLY since the last remote operation, this would cause deferred
triggers on remote servers to still run in READ WRITE mode. Fix this
by synchronizing the mode at commit time.
* The documentation did not match the actual implementation. Update the
documentation to reflect the implementation.
Reported-by: Fujii Masao <masao.fujii@gmail.com>
Author: Etsuro Fujita <etsuro.fujita@gmail.com>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Discussion: https://postgr.es/m/CAHGQGwE4UMaWGOZq1Z7YUTUSg-CgL4yAzO5YaGwTZe1-6Pjg2g%40mail.gmail.com
Backpatch-through: 19
Branch
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REL_19_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/7d3d2db7d5e533fa42a4202c7d308cbb0cbf9333
Modified Files
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contrib/postgres_fdw/connection.c | 54 +++++++++++++++++++++++---
contrib/postgres_fdw/expected/postgres_fdw.out | 30 ++++++++++++--
contrib/postgres_fdw/sql/postgres_fdw.sql | 30 ++++++++++++--
doc/src/sgml/postgres-fdw.sgml | 15 +++----
4 files changed, 106 insertions(+), 23 deletions(-)
