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  1. MariaDB Server
  2. MDEV-35309

ALTER performs vector truncation without WARN_DATA_TRUNCATED or similar warnings/errors

Details

    Description

      ALTER TABLE is able to modify a vector column to a shorter length (which is good). However it does so without the usual warnings/errors produced in a similar situation for other data types.

      create table t (v vector(2));
      		 
      insert into t values (0x3131313132323232);
      		 
      select * from t;
      		 
      alter table t modify v vector(1);
      		 
      select * from t;
      		 
       
      		 
      # Cleanup
      		 
      drop table t;

      7aab5e35d714fc3b6de68f5158072d5ecdf62faa

      		 
      create table t (v vector(2));
      		 
      insert into t values (0x3131313132323232);
      		 
      select * from t;
      		 
      v
      		 
      11112222
      		 
      alter table t modify v vector(1);
      		 
      select * from t;
      		 
      v
      		 
      1111

      In the same situation, modification binary(8) => binary(4) produces WARN_DATA_TRUNCATED (error or warning, depending on the strict mode / ignore clause).

      create table t (v binary(8));
      		 
      insert into t values (0x3131313132323232);
      		 
      select * from t;
      		 
      v
      		 
      11112222
      		 
      alter table t modify v binary(4);
      		 
      bug.t                                    [ fail ]
      		 
              Test ended at 2024-10-31 23:41:15
      		 
       
      		 
      CURRENT_TEST: bug.t
      		 
      mysqltest: At line 4: query 'alter table t modify v binary(4)' failed: WARN_DATA_TRUNCATED (1265): Data truncated for column 'v' at row 1


      set sql_mode='';
      		 
      alter table t modify v binary(4);
      		 
      Warnings:
      		 
      Warning	1265	Data truncated for column 'v' at row 1
      		 
      select * from t;
      		 
      v
      		 
      1111

      Attachments

        Issue Links

          is caused by

          New Feature - A new feature of the product, which has yet to be developed. MDEV-34939 vector search in 11.7

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

          People

            svoj Sergey Vojtovich
            elenst Elena Stepanova
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            Dates

              Created:
              Updated:
              Resolved:

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