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  1. MariaDB Server
  2. MDEV-38701

Optimizer Trace Replay: Q1 2026 Dev Sprint Work 1

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Details

    • Q1/2026 Server Development, Q2/2026 Server Maintenance

    Description

      Hook records_in_range call

      in opt_range.cc in ror_intersect_add() -> ror_scan_selectivity()
      , there is a handler->records_in_range() call.
      We need to hook it: save and return back its value.

      Note that ha_something::multi_range_read_info_const() as well as handler::multi_range_read_info_const() also make calls to handler->records_in_range() and we do NOT need to intercept them.

      Example query that uses index_merge/intersection and depends on records_in_range() value:

      INDEX i1(a, b)
      		 
      INDEX i2(a, c) 
      		 
      select * from t1 where a=1 and b=1 and c=1;

      or try INDEX(c,a), INDEX(b, a).

      Constant tables

      We need to save the rows we've read from constant tables.
      For the moment, let's take the path of least effort:
      We write CREATE TABLE ... statements into captured context.
      For constant tables, also write INSERT INTO tbl VALUES(...) statement.
      That way, we won't need any special replay code.

      Use this function for dumping table rows:

      String dbug_format_row(TABLE *table, const uchar *rec, bool print_names)

      Just make it do quoting.

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          is duplicated by

          New Feature - A new feature of the product, which has yet to be developed. MDEV-27189 Optimizer Trace: save all info needed for replay

          • Major - Major loss of function.
          • Closed
          relates to

          New Feature - A new feature of the product, which has yet to be developed. MDEV-36511 Optimizer Trace replay step #2: dump basic statistics

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. MDEV-36523 Optimizer Trace replay step #3: load basic statistics back

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-38781 Optimizer Trace Replay: Q1 2026 Dev Sprint Work 3

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. MDEV-38923 context capture should work for stored procedures

          • Major - Major loss of function.
          • Open

          Task - A task that needs to be done. MDEV-39042 Bypass exact count optimization when in context replay mode

          • Major - Major loss of function.
          • Open
          split from

          New Feature - A new feature of the product, which has yet to be developed. MDEV-36523 Optimizer Trace replay step #3: load basic statistics back

          • Major - Major loss of function.
          • Closed

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              mariadb-pavithrapandith Pavithra Pandith
              psergei Sergei Petrunia
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                Updated:

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