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  1. MariaDB Server
  2. MDEV-23436

Document all performance_schema memory% instruments

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      MariaDB 10.5 had finally included memory instrumentation based on those from MySQL 5.7, but with some changes. We have some 270 instruments:

      openxs@ao756:~/dbs/5.7$ bin/mysql --socket=/tmp/mariadb.sock -e"select version(), count(*) from performance_schema.setup_instruments where name like 'memory%'" +----------------+----------+
      | version()      | count(*) |
      +----------------+----------+
      | 10.5.5-MariaDB |      270 |
      +----------------+----------+
      openxs@ao756:~/dbs/5.7$ bin/mysql --socket=/tmp/mariadb.sock -e"select name from performance_schema.setup_instruments where name like 'memory%' order by name" | more
      name
      memory/csv/blobroot
      memory/csv/row
      memory/csv/tina_set
      memory/csv/TINA_SHARE
      memory/csv/Transparent_file
      memory/innodb/adaptive hash index
      memory/innodb/btr0btr
      memory/innodb/btr0buf
      memory/innodb/btr0bulk
      memory/innodb/btr0cur
      memory/innodb/btr0pcur
      memory/innodb/btr0sea
      memory/innodb/buf0buf
      memory/innodb/buf0dblwr
      memory/innodb/buf0dump
      memory/innodb/buf_buf_pool
      memory/innodb/dict0dict
      memory/innodb/dict0mem
      memory/innodb/dict0stats
      memory/innodb/dict_stats_bg_recalc_pool_t
      memory/innodb/dict_stats_index_map_t
      memory/innodb/dict_stats_n_diff_on_level
      ...
      

      The purpose of some instruments (like "memory/innodb/adaptive hash index") is clear from the name. But others (like "memory/innodb/btr0pcur" or "memory/sql/MPVIO_EXT::auth_info") hardly makes sense to a typical DBA,

      As we have differences from MySQL, we can not rely on their (non-existent as far as I can see) documentation. I'd like to ask either to document all/key instruments or to add a DOCUMENATION column to the setup_instruments table explaining the purpose of the instrument as in MySQL 8.0, see https://dev.mysql.com/doc/refman/8.0/en/performance-schema-setup-instruments-table.html.

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            Assignee:
            Unassigned Unassigned
            Reporter:
            valerii Valerii Kravchuk
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