postgres

Author SHA1 Message Date

Author	SHA1	Message	Date
Andres Freund	0fd38e1370	Don't skip SQL backends in logical decoding for visibility computation. The logical decoding patchset introduced PROC_IN_LOGICAL_DECODING flag PGXACT flag, that allows such backends to be skipped when computing the xmin horizon/snapshots. That's fine and sensible for walsenders streaming out logical changes, but not at all fine for SQL backends doing logical decoding. If the latter set that flag any change they have performed outside of logical decoding will not be regarded as visible - which e.g. can lead to that change being vacuumed away. Note that not setting the flag for SQL backends isn't particularly bothersome - the SQL backend doesn't do streaming, so it only runs for a limited amount of time. Per buildfarm member 'tick' and Alvaro. Backpatch to 9.4, where logical decoding was introduced.	11 years ago
Andres Freund	89fd41b390	Fix and improve cache invalidation logic for logical decoding. There are basically three situations in which logical decoding needs to perform cache invalidation. During/After replaying a transaction with catalog changes, when skipping a uninteresting transaction that performed catalog changes and when erroring out while replaying a transaction. Unfortunately these three cases were all done slightly differently - partially because `8de3e410fa`, which greatly simplifies matters, got committed in the midst of the development of logical decoding. The actually problematic case was when logical decoding skipped transaction commits (and thus processed invalidations). When used via the SQL interface cache invalidation could access the catalog - bad, because we didn't set up enough state to allow that correctly. It'd not be hard to setup sufficient state, but the simpler solution is to always perform cache invalidation outside a valid transaction. Also make the different cache invalidation cases look as similar as possible, to ease code review. This fixes the assertion failure reported by Antonin Houska in 53EE02D9.7040702@gmail.com. The presented testcase has been expanded into a regression test. Backpatch to 9.4, where logical decoding was introduced.	11 years ago

Andres Freund

Don't skip SQL backends in logical decoding for visibility computation.

The logical decoding patchset introduced PROC_IN_LOGICAL_DECODING flag
PGXACT flag, that allows such backends to be skipped when computing
the xmin horizon/snapshots. That's fine and sensible for walsenders
streaming out logical changes, but not at all fine for SQL backends
doing logical decoding. If the latter set that flag any change they
have performed outside of logical decoding will not be regarded as
visible - which e.g. can lead to that change being vacuumed away.

Note that not setting the flag for SQL backends isn't particularly
bothersome - the SQL backend doesn't do streaming, so it only runs for
a limited amount of time.

Per buildfarm member 'tick' and Alvaro.

Backpatch to 9.4, where logical decoding was introduced.

11 years ago

Andres Freund

89fd41b390

Fix and improve cache invalidation logic for logical decoding.

There are basically three situations in which logical decoding needs
to perform cache invalidation. During/After replaying a transaction
with catalog changes, when skipping a uninteresting transaction that
performed catalog changes and when erroring out while replaying a
transaction. Unfortunately these three cases were all done slightly
differently - partially because 8de3e410fa, which greatly simplifies
matters, got committed in the midst of the development of logical
decoding.

The actually problematic case was when logical decoding skipped
transaction commits (and thus processed invalidations). When used via
the SQL interface cache invalidation could access the catalog - bad,
because we didn't set up enough state to allow that correctly. It'd
not be hard to setup sufficient state, but the simpler solution is to
always perform cache invalidation outside a valid transaction.

Also make the different cache invalidation cases look as similar as
possible, to ease code review.

This fixes the assertion failure reported by Antonin Houska in
53EE02D9.7040702@gmail.com. The presented testcase has been expanded
into a regression test.

Backpatch to 9.4, where logical decoding was introduced.

11 years ago

2 Commits (49340627f9821e447f135455d942f7d5e96cae6d)