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freebsd:zfs [2020/10/26 05:57] – sleepyfreebsd:zfs [2025/07/07 23:10] (current) – external edit 127.0.0.1
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 ===== PostgreSQL ===== ===== PostgreSQL =====
 +~~REFNOTES~~
 ==== notes ==== ==== notes ====
   * use ZFS's cache is postgresql dataset exceeds RAM, use postgres's cache if dataset fits in RAM   * use ZFS's cache is postgresql dataset exceeds RAM, use postgres's cache if dataset fits in RAM
     * disable postgres cache, enable ZFS cache     * disable postgres cache, enable ZFS cache
     * enable postgres cache, disable ZFS cache     * enable postgres cache, disable ZFS cache
 +
 ==== zfs ==== ==== zfs ====
   * **atime=off** -- disable access time recording for files when they are read   * **atime=off** -- disable access time recording for files when they are read
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   * disable PostgreSQL TOAST compression   * disable PostgreSQL TOAST compression
   * dedicate 15%-25% physical ram to ARC, and 50% to shared_buffers   * dedicate 15%-25% physical ram to ARC, and 50% to shared_buffers
 +=== raw benchmark data ===
 +{{tablelayout?tableSort=1}}
 +^ pgbench -c 10 -j 2 -t 10000 ^ inc. connections est. ^ exc. connections est. ^ latency ^
 +| BASE |  6775 |  6776 |  1.476 ms |
 +| primarycache=metadata |  3850 |  3850 |  2.597 ms |
 +| primarycache=metadata compression=lz4 |  4815 |  4816 |  2.077 ms |
 +| primarycache=metadata compression=lz4 recordsize=16k |  4160 |  4160 |  2.404 ms |
 +| primarycache=metadata, compression=lz4, recordsize=16k, atime=off |  3415 |  3415 |  2.928 ms |
 +| primarycache=metadata, compression=lz4, recordsize=8k, atime=off |  4362 |  4363 |  2.292 ms |
 +| primarycache=metadata, compression=lz4, recordsize=8k, atime=off, \\ shared_buffers=2048MB |  5862 |  5863 |  1.706 ms |
 +| primarycache=metadata, compression=lz4, recordsize=16k, atime=off, \\ shared_buffers=2048MB |  5819 |  5820 |  1.718 ms |
 +| compression=lz4, recordsize=16k, atime=off, \\ shared_buffers=2048MB |  7628 |  7628 |  1.311 ms |
 +| compression=lz4, recordsize=16k, atime=off, \\ shared_buffers=4096MB |  7332 |  7333 |  1.364 ms |
 +| compression=lz4, recordsize=16k, atime=off, logbias=throughput, \\ shared_buffers=4096MB, synchronous_commit=off |  27052 |   27067 |  0.370 ms |
 +| compression=lz4, recordsize=16k, atime=off, logbias=throughput, \\ shared_buffers=4096MB, synchronous_commit=off, full_page_writes=off |  30348 |  30366 |  0.330 ms |
 +
  
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freebsd/zfs.1603691868.txt.gz · Last modified: (external edit)