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  • 2 commits
  • 29 files changed
  • 2 contributors

Commits on Oct 30, 2025

  1. Expand HOT update path to include expression and partial indexes 

    Expression indexes have historically been considered "hot blocking", but
this choice significanly impares the utility of the JSONB data type as
all indexes referencing data within documents are formed using
expressions. Thus an update to a JSONB column will prevent the HOT path
and force all indexes across all columns to be updated.

Updates to attributes referenced by partial indexes may fall entirely
outside of the range of values maintained by an index, but despite that
they are effectively "HOT blocking".  This too is changed to allow for
HOT updates in cases where the predicate on the index is not satisfied
for either the old or the new tuple.

It appears that the primary reason for not checking expression indexes
or the expressions forming partial indexes, besides the overhead of the
expression itself, was that the execution of expression could
self-deadlock.  Here we are careful to hold the pin, but not the buffer
lock when evaluating the expressions.  We are careful to only evaluate
expressions when they are both in the modified set for the update and
the modified attribute is only referenced by vars in those expressions.

It is important to note that this patch was inspired by, but is a
significant departure from, a previous patch.
https://postgr.es/m/4d9928ee-a9e6-15f9-9c82-5981f13ffca6%40postgrespro.ru
applied in c203d6c and later reverted
in 05f84605dbeb9cf8279a157234b24bbb706c5256.

Signed-off-by: Greg Burd <[email protected]>
    @gburd
    gburd authored and Commitfest Bot committed Oct 30, 2025
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  2. [CF 5556] v18 - Expanding HOT updates for expression and partial indexes 

    This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5556

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/[email protected]
Author(s): Greg Burd
    Commitfest Bot committed Oct 30, 2025
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