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  1. MariaDB Server
  2. MDEV-38457

pseudo_slave_mode nor pseudo_thread_id can be enabled after creating a GTT, starting a trx and querying the GTT

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    Description

      CREATE TABLE t (c INT);
      		 
      BEGIN;
      		 
      SELECT * FROM t;
      		 
      SET pseudo_slave_mode=1;

      As well as 

      CREATE TEMPORARY TABLE t (c INT);
      		 
      BEGIN;
      		 
      SELECT * FROM t;
      		 
      SET pseudo_slave_mode=1;

      Work fine:

      MDEV-35915-v10 CS 12.2.0 2ef81706c8c4782b2f8a45a05ac90377403de2e1 (Debug, Clang 21.1.3-20250923) Build 31/12/2025

      		 
      12.2.0-dbg>SET pseudo_slave_mode=1;
      		 
      Query OK, 0 rows affected (0.000 sec)

      However, when using a GTT instead of a TT or base table:

      CREATE GLOBAL TEMPORARY TABLE t (c INT);
      		 
      BEGIN;
      		 
      SELECT * FROM t;
      		 
      SET pseudo_slave_mode=1;

      We see an error:

      MDEV-35915-v10 CS 12.2.0 2ef81706c8c4782b2f8a45a05ac90377403de2e1 (Debug, Clang 21.1.3-20250923) Build 31/12/2025

      		 
      12.2.0-dbg>CREATE GLOBAL TEMPORARY TABLE t (c INT);
      		 
      Query OK, 0 rows affected (0.008 sec)
      		 
       
      		 
      12.2.0-dbg>BEGIN;
      		 
      Query OK, 0 rows affected (0.000 sec)
      		 
       
      		 
      12.2.0-dbg>SELECT * FROM t;
      		 
      Empty set (0.001 sec)
      		 
       
      		 
      12.2.0-dbg>SET pseudo_slave_mode=1;
      		 
      ERROR 1231 (42000): Variable 'pseudo_slave_mode' can't be set to the value of '1'

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        Issue Links

          blocks

          Bug - A problem which impairs or prevents the functions of the product. MDEV-37720 use-after-free on CREATE OR REPLACE GTT under LOCK TABLES and pseudo_slave_mode

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-37872 SIGSEGV in MDL_context::release_loc, Assertion `mdl_ticket->m_duration == MDL_TRANSACTION && duration != MDL_TRANSACTION' failed, ASAN heap-use-after-free in I_P_List on CoR

          • Critical - Crashes, loss of data, severe memory leak.
          • In Testing
          is caused by

          New Feature - A new feature of the product, which has yet to be developed. MDEV-35915 Implement Global temporary tables

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

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            People

              nikitamalyavin Nikita Malyavin
              Roel Roel Van de Paar
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              Dates

                Created:
                Updated:
                Resolved:

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