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  1. MariaDB Server
  2. MDEV-26790

InnoDB read-ahead may cause page writes

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    Description

      The following stack trace could cause reduced performance in cases when the speculative read-ahead is futile, and some useful pages are evicted as a result:

      10.5

      buf_LRU_get_free_block
      buf_page_init_for_read
      buf_read_page_low
      buf_read_page_background
      btr_cur_prefetch_siblings
      

      It could be more useful to only attempt read-ahead if a free block is available in the buffer pool without evicting any page that:

      1. is not marked as freed, or
      2. is not marked as dirty

      Furthermore, we should probably avoid read-ahead altogether for temporary tables.

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            origin/bb-10.11-MDEV-30216-MDEV-26790 c85c38683af18c5851afa5382aa7aaf869536176 2023-01-13T16:46:20+02:00
            performed well in RQG testing. Bad effects observed were in the main trees too.

            mleich Matthias Leich added a comment - origin/bb-10.11- MDEV-30216 - MDEV-26790 c85c38683af18c5851afa5382aa7aaf869536176 2023-01-13T16:46:20+02:00 performed well in RQG testing. Bad effects observed were in the main trees too.

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              marko Marko Mäkelä
              marko Marko Mäkelä
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                Updated:
                Resolved:

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