Horton

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

Andres Freund <andres@anarazel.de>

View thread View on postgr.es
From: Andres Freund <andres@anarazel.de>
To: David Rowley <dgrowleyml@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, 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: 2023-02-11T22:33:40Z
Lists: pgsql-hackers 
Hi,

On 2023-02-11 14:25:06 -0800, Andres Freund wrote:
> On 2023-01-20 13:40:55 +1300, David Rowley wrote:
> > v2-0004:
> > 
> > 5. Is it worth having two versions of PinLocalBuffer() one to adjust
> > the usage count and one that does not? Couldn't the version that does
> > not adjust the count skip doing pg_atomic_read_u32()?
> 
> I think it'd be nicer to just move the read inside the if
> (adjust_usagecount). That way the rest of the function doesn't have to be
> duplicated.

Ah, no, we need it for the return value. No current users of
  PinLocalBuffer(adjust_usagecount = false)
need the return value, but I don't think that's necessarily the case.

I'm somewhat inclined to not duplicate it, but if you think it's worth it,
I'll do that.

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.