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  1. MariaDB Server
  2. MDEV-35673

Correlated subquery problems causing wrong results and server crash

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Details

    • Can result in hang or crash
    • Correlated subqueries causing incorrect results and crashes

    Description

      We have a general problem with relationship attribute data relating to Items representing subselects, particularly when these subselects are correlated to upper level selects via the use of outer references. How these attributes change during the various phases of execution, i.e.

      {prepare, optimize, execute}

      within each of

      {conventional, stored procedure, prepared statement, 1st execution, subsequent execution}

      is inconsistent.

      In this series of commits

      1 & 2) trivial changes to restrict building of lists not needed during certain operations.

      3) MDEV-30073. Igor's commit dealing with Items that need to survive between executions being allocated in statement memory.

      4 & 5) some fix-ups and suggestions from Monty.

      6) MDEV-32294. Code directly "inspired" by mysql's collapsing structures during query merges.

      7) MDEV-35673 during the development of main.outer_reference MTR file, a number of problems were encountered with correlated subselects. Searching outstanding issues revealed a number of similar problems. This patch deals with most of those issues by

      • Correcting the used table map for subquery/expressions which is currently, at times, incorrect. This involves allocating some items on statement memory, building and managing a list of items resolved in inner subqueries, and altering how table maps are accumulated in expressions.
      • Extending the structures updated when queries are merged, an extension of MDEV-32294 but this code is unrelated to mysql.
      • Avoiding un-needed processing during (re-)fixing items, solving many crashes. We have enough information gathered during the first fix_fields call to avoid calling fix_outer_field during any subsequent fix_fields call.

      Attachments

        Issue Links

          blocks

          Bug - A problem which impairs or prevents the functions of the product. MDEV-30756 Crash in get_sort_by_table / make_join_statistics / update_depend_map_for_order, various UBSAN pointer issues

          • Major - Major loss of function.
          • Stalled

          Bug - A problem which impairs or prevents the functions of the product. MDEV-31269 Various SIGSEGV crashes, UBSAN issues and memory corruption on 2nd PS execution caused by exists-to-in

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-32297 Failing queries with outer references to views in degenerated selects

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-35277 SIGSEGV and UBSAN null-pointer-use in get_sort_by_table on SELECT...EXISTS

          • Major - Major loss of function.
          • Stalled

          Bug - A problem which impairs or prevents the functions of the product. MDEV-35565 Server crashes simplifying group by <subquery>

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-35676 Wrong result on 2nd execution with outer reference

          • Major - Major loss of function.
          • Open
          is blocked by

          Bug - A problem which impairs or prevents the functions of the product. MDEV-30073 Wrong result on 2nd execution of PS for query with NOT EXISTS

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-32294 fix_fields() problem with inconsistent outer context paths

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-31270 Wrong result on 2nd execution for PS with NULL on MAX function and IN predicate

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-37448 MariaDB Server Crashes Calling Stored Procedure

          • Major - Major loss of function.
          • Confirmed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-6054 ER_BAD_FIELD_ERROR (Unknown column in where clause) on the 2nd execution of PS

          • Major - Major loss of function.
          • Stalled

          Bug - A problem which impairs or prevents the functions of the product. MDEV-26944 Server crash on selecting some data from information_schema

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-30756 Crash in get_sort_by_table / make_join_statistics / update_depend_map_for_order, various UBSAN pointer issues

          • Major - Major loss of function.
          • Stalled

          Bug - A problem which impairs or prevents the functions of the product. MDEV-31937 Server crash on 2nd execution query SELECT from view of prepare statement if query has impossible HAVING

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-32702 Assertion Failed at /mariadb-11.3.0/sql/item.cc:5807

          • Major - Major loss of function.
          • Confirmed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-32766 Segmentation fault at /mariadb-11.3.0/sql/sql_select.cc:23373

          • Major - Major loss of function.
          • Confirmed

          Activity

            People

              psergei Sergei Petrunia
              Johnston Rex Johnston
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              Dates

                Created:
                Updated:

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