Horton

Re: Removing more vacuumlazy.c special cases, relfrozenxid optimizations

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Andres Freund <andres@anarazel.de>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-04-01T17:54:14Z
Lists: pgsql-hackers

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On Thu, Mar 31, 2022 at 11:19 AM Peter Geoghegan <pg@bowt.ie> wrote:
> The assert is "Assert(diff > 0)", and not "Assert(diff >= 0)".

Attached is v15. I plan to commit the first two patches (the most
substantial two patches by far) in the next couple of days, barring
objections.

v15 removes this "Assert(diff > 0)" assertion from 0001. It's not
adding any value, now that the underlying issue that it accidentally
brought to light is well understood (there are still more robust
assertions to the relfrozenxid/relminmxid invariants). "Assert(diff >
0)" is liable to fail until the underlying bug on HEAD is fixed, which
can be treated as separate work.

I also refined the WARNING patch in v15. It now actually issues
WARNINGs (rather than PANICs, which were just a temporary debugging
measure in v14). Also fixed a compiler warning in this patch, based on
a complaint from CFBot's CompilerWarnings task. I can delay commiting
this WARNING patch until right before feature freeze. Seems best to
give others more opportunity for comments.

-- 
Peter Geoghegan

Commits

  1. Have VACUUM warn on relfrozenxid "in the future".

  2. vacuumlazy.c: Further consolidate resource allocation.

  3. Generalize how VACUUM skips all-frozen pages.

  4. Set relfrozenxid to oldest extant XID seen by VACUUM.

  5. Doc: Add relfrozenxid Tip to XID wraparound section.

  6. vacuumlazy.c: document vistest and OldestXmin.

  7. Increase hash_mem_multiplier default to 2.0.

  8. Consolidate VACUUM xid cutoff logic.

  9. Add VACUUM instrumentation for scanned pages, relfrozenxid.

  10. Simplify lazy_scan_heap's handling of scanned pages.

  11. Try to stabilize reloptions test, again.

  12. Unify VACUUM VERBOSE and autovacuum logging.

  13. Fix possible HOT corruption when RECENTLY_DEAD changes to DEAD while pruning.

  14. pg_resetxlog: add option to set oldest xid & use by pg_upgrade

  15. Teach VACUUM to bypass unnecessary index vacuuming.

  16. Centralize horizon determination for temp tables, fixing bug due to skew.

  17. pg_surgery: Try to stabilize regression tests.

  18. Add "split after new tuple" nbtree optimization.

  19. Fix bugs in vacuum of shared rels, by keeping their relcache entries current.

  20. Avoid useless truncation attempts during VACUUM.

  21. Only skip pages marked as clean in the visibility map, if the last 32

  22. Fix recently-understood problems with handling of XID freezing, particularly