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  1. Percona Server
  2. PS-3936

key_block_size implicitly changed with MEMORY engine(TEXT/BLOB/JSON) columns

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      Hi,
      With upstream checked with small columns - INT/VARCHAR and there is no such problem, where the key_block_size changed and added to show create table output, as well as with PS.

      With BLOB/JSON/TEXT columns the result is:

      5.7.21>show create table t2\G
      *************************** 1. row ***************************
             Table: t2
      Create Table: CREATE TABLE `t2` (
        `f4` json DEFAULT NULL
      ) ENGINE=MEMORY DEFAULT CHARSET=utf8
      1 row in set (0.00 sec)
      
      5.7.21>alter table t2 compression='none';
      Query OK, 0 rows affected (0.10 sec)
      Records: 0  Duplicates: 0  Warnings: 0
      
      5.7.21>show create table t2\G
      *************************** 1. row ***************************
             Table: t2
      Create Table: CREATE TABLE `t2` (
        `f4` json DEFAULT NULL
      ) ENGINE=MEMORY DEFAULT CHARSET=utf8 KEY_BLOCK_SIZE=256 COMPRESSION='none'
      1 row in set (0.00 sec)
      

      Another test:

      5.7.21>alter table t2 key_block_size=124;
      Query OK, 0 rows affected (0.10 sec)
      Records: 0  Duplicates: 0  Warnings: 0
      
      
      5.7.21>show create table t2\G
      *************************** 1. row ***************************
             Table: t2
      Create Table: CREATE TABLE `t2` (
        `f4` json DEFAULT NULL
      ) ENGINE=MEMORY DEFAULT CHARSET=utf8 KEY_BLOCK_SIZE=124 COMPRESSION='none'
      1 row in set (0.00 sec)
      
      
      5.7.21>alter table t2 compression='none';
      Query OK, 0 rows affected (0.11 sec)
      Records: 0  Duplicates: 0  Warnings: 0
      
      
      5.7.21>show create table t2\G
      *************************** 1. row ***************************
             Table: t2
      Create Table: CREATE TABLE `t2` (
        `f4` json DEFAULT NULL
      ) ENGINE=MEMORY DEFAULT CHARSET=utf8 KEY_BLOCK_SIZE=256 COMPRESSION='none'
      1 row in set (0.00 sec)
      

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                • Assignee:
                  zsolt.parragi Zsolt Parragi
                  Reporter:
                  shahriyar.rzayev Shahriyar Rzayev (Inactive)
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                    Resolved:

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