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  1. MariaDB Server
  2. MDEV-34431

More fine grained control of spin loops could be useful

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    • Q3/2025 Maintenance

    Description

      In an attempt to address MDEV-34178, I enabled spin loops on dict_index_t::lock. This helps in some workloads and causes performance degradation in others, especially when there are large numbers of concurrent connections.

      It could make sense to enable spin loops on a case-by-case basis, or to introduce a configuration parameter for choosing when index tree latch acquisition should include spin loops.

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        1. 150_revert_34178_flamegraph.svg
          1.76 MB
          Rahul Raj
        2. 150_vu_11_8_MDEV_19749_flamegraph.svg
          1.81 MB
          Rahul Raj
        3. 80_revert_34178_flamegraph.svg
          1.79 MB
          Rahul Raj
        4. 80_vu_11_8_MDEV_19749_flamegraph.svg
          1.43 MB
          Rahul Raj
        5. Image_1_Default_Config.png
          48 kB
          Rahul Raj
        6. Image_2_Commit_ID-6c67a1acd.png
          51 kB
          Rahul Raj
        7. Image_3_commit_ID_5ed84da8e.png
          51 kB
          Rahul Raj
        8. Image_4_steve changes vs Marko_latest_commit.png
          45 kB
          Rahul Raj
        9. MDEV-34431-sysbench.txt
          5 kB
          Marko Mäkelä
        10. Performance_graph.png
          43 kB
          Rahul Raj
        11. thread_pool_size_spin_parameters.png
          6 kB
          Rahul Raj

        Issue Links

          is blocked by

          Bug - A problem which impairs or prevents the functions of the product. MDEV-34515 Contention between secondary index UPDATE and purge due to large innodb_purge_batch_size

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-34759 buf_page_get_low() is unnecessarily acquiring exclusive latch on secondary index pages

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-34791 Redundant page lookups hurt performance

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-37244 buf_read_page() could return a buffer-fixed block

          • Major - Major loss of function.
          • In Progress

          Bug - A problem which impairs or prevents the functions of the product. MDEV-34178 Performance regression with IO-bound insert benchmark

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

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              marko Marko Mäkelä
              marko Marko Mäkelä
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              Dates

                Created:
                Updated:

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