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  1. MariaDB Server
  2. MDEV-35069

IMPORT TABLESPACE does not work for tables with vector, although allowed

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      Since the vector index is a separate .ibd file, not surprisingly DISCARD / IMPORT TABLESPACE on a table with such index doesn't work "out of the box". That is, it still handles the main tablespace, but does nothing to the vector one – DISCARD doesn't remove it, IMPORT ignores it. While doing so it doesn't produce any errors or warnings.
      I think it can lead to human errors and to unexpected results later:

      --source include/have_innodb.inc
       
      --let $datadir= `select @@datadir`
       
      create table t (a int, v blob not null, vector(v)) engine=InnoDB;
      insert into t values (1,x'00000000'),(1,x'00000000');
      select a, vec_totext(v) from t;
      select a, vec_totext(v) from t order by vec_distance_euclidean(v,x'00000000') limit 1;
       
      flush table t for export;
      --list_files $datadir/test/
      --copy_file $datadir/test/t.ibd $datadir/test/t.ibd.save
      --copy_file $datadir/test/t#i#00.ibd $datadir/test/t#i#00.ibd.save
      --copy_file $datadir/test/t.cfg $datadir/test/t.cfg.save
      unlock tables;
      create or replace table t (a int, v blob not null, vector(v)) engine=InnoDB;
      alter table t discard tablespace;
      --list_files $datadir/test/
      --remove_file $datadir/test/t#i#00.ibd
      --move_file $datadir/test/t#i#00.ibd.save $datadir/test/t#i#00.ibd
      --move_file $datadir/test/t.ibd.save $datadir/test/t.ibd
      --move_file $datadir/test/t.cfg.save $datadir/test/t.cfg
      alter table t import tablespace;
      flush tables;
      select a, vec_totext(v) from t;
      select a, vec_totext(v) from t order by vec_distance_euclidean(v,x'00000000') limit 1;
       
      --source include/restart_mysqld.inc
       
      select a, vec_totext(v) from t;
      select a, vec_totext(v) from t order by vec_distance_euclidean(v,x'00000000') limit 1;
       
      # Cleanup
      drop table t;
      

      In the above, everything up to the server restart "works", import succeeds, the table contents exists, the key seems to exist, only it is empty. FLUSH TABLES doesn't help either:

      flush tables;
      select a, vec_totext(v) from t;
      a	vec_totext(v)
      1	[0.000000]
      1	[0.000000]
      select a, vec_totext(v) from t order by vec_distance_euclidean(v,x'00000000') limit 1;
      a	vec_totext(v)
      # restart
      

      Only after server restart InnoDB notices that something is wrong:

      # restart
      select a, vec_totext(v) from t;
      a	vec_totext(v)
      1	[0.000000]
      1	[0.000000]
      select a, vec_totext(v) from t order by vec_distance_euclidean(v,x'00000000') limit 1;
      bug.t                                    [ fail ]
              Test ended at 2024-10-03 12:27:38
       
      CURRENT_TEST: bug.t
      mysqltest: At line 31: query 'select a, vec_totext(v) from t order by vec_distance_euclidean(v,x'00000000') limit 1' failed: ER_TABLE_CORRUPT (1877): Table `test`.`t#i#00` is corrupted. Please drop the table and recreate.
      

      bb-11.6-MDEV-32887-vector 77be73c489fb7c21ca58e78cef10e0c166f293d8

      2024-10-03 12:27:38 0 [ERROR] InnoDB: Expected tablespace id 11 but found 0 in the file ./test/t#i#00.ibd
      2024-10-03 12:27:38 0 [Note] InnoDB: Buffer pool(s) load completed at 241003 12:27:38
      ...
      2024-10-03 12:27:38 3 [ERROR] InnoDB: Expected tablespace id 11 but found 0 in the file ./test/t#i#00.ibd
      2024-10-03 12:27:38 3 [ERROR] mariadbd: Table `test`.`t#i#00` is corrupted. Please drop the table and recreate.
      2024-10-03 12:27:38 3 [ERROR] Got error 126 when reading table './test/t'
      2024-10-03 12:27:38 3 [ERROR] mariadbd: Index for table 't' is corrupt; try to repair it
      

      As a short-term solution, I suppose DISCARD and IMPORT on tables with vector keys should be forbidden. However, for vector-containing tables specifically, given that their creation/population is so expensive, the ability to move tablespaces could be attractive.

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              serg Sergei Golubchik
              elenst Elena Stepanova
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