Horton

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

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Andres Freund <andres@anarazel.de>, vignesh C <vignesh21@gmail.com>
Cc: pgsql-hackers@postgresql.org, Thomas Munro <thomas.munro@gmail.com>, Melanie Plageman <melanieplageman@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, Robert Haas <robertmhaas@gmail.com>
Date: 2023-02-21T15:40:31Z
Lists: pgsql-hackers 
> v2-0006-bufmgr-Support-multiple-in-progress-IOs-by-using-.patch

This looks straightforward. My only concern is that it changes the order 
that things happen at abort. Currently, AbortBufferIO() is called very 
early in AbortTransaction(), and this patch moves it much later. I don't 
see any immediate problems from that, but it feels scary.


> @@ -2689,7 +2685,6 @@ InitBufferPoolAccess(void)
>  static void
>  AtProcExit_Buffers(int code, Datum arg)
>  {
> -	AbortBufferIO();
>  	UnlockBuffers();
>  
>  	CheckForBufferLeaks();

Hmm, do we call AbortTransaction() and ResourceOwnerRelease() on 
elog(FATAL)? Do we need to worry about that?

- Heikki

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.