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  1. MariaDB Server
  2. MDEV-36069

Remove dict_table_t::n_ref_count; implement event based table eviction

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    Description

      A table reference count was introduced in MySQL 5.6 to serve two purposes:

      • Allow tables to be evicted from the InnoDB data dictionary cache: dict_sys.evict_table_LRU()
      • After FLUSH TABLES, allow InnoDB persistent statistics to be reloaded. This logic would be simplified in MDEV-35000.

      If as part of MDEV-25292 or MDEV-36493 we will change the metadata lock acquisition in DDL operations, we could fully protect the purge of committed InnoDB history with metadata locks and would not need any reference counts.

      Then, the dict_sys.evict_table_LRU() could then be made event-based, coupled more tightly with the table definition cache and FLUSH TABLES. This would reduce periodic contention on dict_sys.latch.

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          is blocked by

          New Feature - A new feature of the product, which has yet to be developed. MDEV-25292 Atomic CREATE OR REPLACE TABLE

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-35000 dict_table_close() breaks innodb_stats_auto_recalc

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-36493 Atomic CREATE OR REPLACE ... SELECT blocks InnoDB purge

          • Major - Major loss of function.
          • Confirmed

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              marko Marko Mäkelä
              marko Marko Mäkelä
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