Horton

Re: refactoring relation extension and BufferAlloc(), faster COPY

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Melanie Plageman <melanieplageman@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Alvaro Herrera <alvherre@alvh.no-ip.org>, vignesh C <vignesh21@gmail.com>, pgsql-hackers@postgresql.org, Thomas Munro <thomas.munro@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, Robert Haas <robertmhaas@gmail.com>
Date: 2023-04-07T08:39:11Z
Lists: pgsql-hackers 
Hi,

On 2023-04-06 18:15:14 -0700, Andres Freund wrote:
> I think it might be worth having a C test for some of the bufmgr.c API. Things
> like testing that retrying a failed relation extension works the second time
> round.

A few hours after this I hit a stupid copy-pasto (21d7c05a5cf) that would
hopefully have been uncovered by such a test...

I guess we could even test this specific instance without a more complicated
framework.  Create table with some data, rename the file, checkpoint - should
fail, rename back, checkpoint - should succeed.

It's much harder to exercise the error paths inside the backend extending the
relation unfortunately, because we require the file to be opened rw before
doing much. And once the FD is open, removing the permissions doesn't help.
The least complicated approach I scan see is creating directory qutoas, but
that's quite file system specific...

Greetings,

Andres Freund

Commits

  1. lwlock: Fix quadratic behavior with very long wait lists

  2. Support RBM_ZERO_AND_CLEANUP_LOCK in ExtendBufferedRelTo(), add tests

  3. Use ExtendBufferedRelTo() in XLogReadBufferExtended()

  4. hio: Use ExtendBufferedRelBy() to extend tables more efficiently

  5. heapam: Pass number of required pages to RelationGetBufferForTuple()

  6. Convert many uses of ReadBuffer[Extended](P_NEW) to ExtendBufferedRel()

  7. Use ExtendBufferedRelTo() in {vm,fsm}_extend()

  8. bufmgr: Introduce infrastructure for faster relation extension

  9. bufmgr: Support multiple in-progress IOs by using resowner

  10. bufmgr: Acquire and clean victim buffer separately

  11. bufmgr: Add Pin/UnpinLocalBuffer()

  12. bufmgr: Add some more error checking [infrastructure] around pinning

  13. Add smgrzeroextend(), FileZero(), FileFallocate()

  14. Don't initialize page in {vm,fsm}_extend(), not needed

  15. bufmgr: Remove buffer-write-dirty tracepoints

  16. hio: Release extension lock before initializing page / pinning VM

  17. bufmgr: Fix undefined behaviour with, unrealistically, large temp_buffers

  18. Fix memory leak and inefficiency in CREATE DATABASE ... STRATEGY WAL_LOG

  19. pgstat: Track more detailed relation IO statistics

  20. Use unnamed POSIX semaphores on Cygwin.

  21. Include RelFileLocator fields individually in BufferTag.