pgsql: Introduce macros for WAL block reference IDs of some heap record - Mailing list pgsql-committers

From Melanie Plageman
Subject pgsql: Introduce macros for WAL block reference IDs of some heap record
Date
Msg-id E1wk7Dk-000M0X-0J@gemulon.postgresql.org
Whole thread
List pgsql-committers
Introduce macros for WAL block reference IDs of some heap record types

When registering a buffer with the WAL machinery, the caller assigns it a
block reference ID, and replay must read each block back by that same ID.
Today these IDs are bare integers assigned by convention (0, 1, 2, ...),
which is easy to follow when a record registers a single block, or when the
blocks are handled during replay in their registration order.

An upcoming bug fix registers up to two visibility map blocks in addition
to the heap block(s) when clearing the VM, and these are not handled during
replay in a straightforward 1:1, in-registration-order fashion. Relying on
bare integers for the block IDs in that case is error-prone.

Introduce macros naming the block reference IDs for the heap record types
that the upcoming commit extends to register visibility map blocks, so the
registration and replay sites refer to the same block by a meaningful name.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/66mqpfyti3qhfttcsv6r2lbvqqd32rrmpn6i47ovrsnvguts46%40gou54xc>
Backpatch through: 17

Branch
------
REL_19_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/56bf5fa5d67a0cea97a8b456a3834749b3146f95

Modified Files
--------------
src/backend/access/heap/heapam.c      | 45 ++++++++++++++++------------
src/backend/access/heap/heapam_xlog.c | 56 ++++++++++++++++++++++-------------
src/include/access/heapam_xlog.h      | 29 +++++++++++++-----
3 files changed, 84 insertions(+), 46 deletions(-)


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