Allow decoding at prepare time in ReorderBuffer

Enterprise / PostgreSQL - Amit Kapila [postgresql.org] - 4 January 2021 03:04 UTC

This patch allows PREPARE-time decoding of two-phase transactions (if the output plugin supports this capability), in which case the transactions are replayed at PREPARE and then committed later when COMMIT PREPARED arrives.

Now that we decode the changes before the commit, the concurrent aborts may cause failures when the output plugin consults catalogs (both system and user-defined).

We detect such failures with a special sqlerrcode ERRCODE_TRANSACTION_ROLLBACK introduced by commit 7259736a6e and stop decoding the remaining changes. Then we rollback the changes when rollback prepared is encountered.

Author: Ajin Cherian and Amit Kapila based on previous work by Nikhil Sontakke and Stas Kelvich

a271a1b50e Allow decoding at prepare time in ReorderBuffer.
contrib/test_decoding/Makefile | 2 +-
contrib/test_decoding/expected/twophase.out | 235 +++++++++++
contrib/test_decoding/expected/twophase_stream.out | 147 +++++++
contrib/test_decoding/sql/twophase.sql | 112 ++++++
contrib/test_decoding/sql/twophase_stream.sql | 45 +++
doc/src/sgml/logicaldecoding.sgml | 104 ++++-
src/backend/replication/logical/decode.c | 286 ++++++++++++--
src/backend/replication/logical/logical.c | 9 -
src/backend/replication/logical/reorderbuffer.c | 432 +++++++++++++++++----
src/backend/replication/logical/snapbuild.c | 7 +
src/include/replication/reorderbuffer.h | 33 +-
11 files changed, 1296 insertions(+), 116 deletions(-)

Upstream: git.postgresql.org


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