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  1. MariaDB Server
  2. MDEV-20194

Warnings inconsistently issued upon CHECK on table from older versions

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    Description

      Note: I'm fine with closing it as not a bug as long as all aspects of the new behavior are considered and confirmed to be expected. It was discussed a little on slack as a probably innocent consequence of MDEV-19292 fix, but I am not sure there was a final conclusion.

      Here is an example of the table:

      CREATE TABLE t1 (
      		 
        `c01` int(10) unsigned zerofill NOT NULL DEFAULT 0000000000,
      		 
        `c03` varchar(1024) NOT NULL DEFAULT '',
      		 
        `c04` timestamp(6) NOT NULL DEFAULT current_timestamp(6) ON UPDATE current_timestamp(6),
      		 
        `c06` double(16,8) DEFAULT NULL COMMENT 'Percentage',
      		 
        `c07` date DEFAULT NULL,
      		 
        `c12` varchar(64) GENERATED ALWAYS AS (concat(`c09`,' ',`c10`)) VIRTUAL,
      		 
        `c05` longblob NOT NULL DEFAULT '',
      		 
        `c11` varchar(64) GENERATED ALWAYS AS (concat(`c09`,' ',`c10`)) PERSISTENT,
      		 
        `c08` text DEFAULT '',
      		 
        `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
      		 
        `c02` char(3) NOT NULL DEFAULT '',
      		 
        `c10` bigint(20) DEFAULT NULL COMMENT 'Y',
      		 
        `c09` bigint(20) DEFAULT NULL COMMENT 'X',
      		 
        PRIMARY KEY (`id`),
      		 
        UNIQUE KEY `idx1` (`c01`,`c02`),
      		 
        KEY `idx2` (`c05`(128))
      		 
      ) ENGINE=InnoDB DEFAULT CHARSET=latin1 ROW_FORMAT=COMPACT;

      Server options: --innodb-compression-algorithm=none --innodb-page-size=4K, otherwise defaults.

      The table gets created on a pre-MDEV-19292 server with without any warnings (on a post-MDEV-19292 server it gets rejected).
      When a post-MDEV-19292 server starts on the old datadir, CHECK TABLE t1 produces the warning:

      10.2 fc77a66c

      		 
      +---------+-------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      | Table   | Op    | Msg_type | Msg_text                                                                                                                                                                                            |
      		 
      +---------+-------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      | test.t1 | check | Warning  | Row size too large (> 1982). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, BLOB prefix of 768 bytes is stored inline. |
      		 
      | test.t1 | check | status   | OK                                                                                                                                                                                                  |
      		 
      +---------+-------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

      First, it's unclear whether MDEV-19292 patch was supposed to affect REDUNDANT / COMPACT tables at all.

      Secondly, the warning, if it's true, could have been helpful if it was reliable; but it is only issued on the first opening of the table:

      MariaDB [test]> check table t1;
      		 
      +---------+-------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      | Table   | Op    | Msg_type | Msg_text                                                                                                                                                                                            |
      		 
      +---------+-------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      | test.t1 | check | Warning  | Row size too large (> 1982). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, BLOB prefix of 768 bytes is stored inline. |
      		 
      | test.t1 | check | status   | OK                                                                                                                                                                                                  |
      		 
      +---------+-------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      2 rows in set (0.005 sec)
      		 
       
      		 
      MariaDB [test]> check table t1;
      		 
      +---------+-------+----------+----------+
      		 
      | Table   | Op    | Msg_type | Msg_text |
      		 
      +---------+-------+----------+----------+
      		 
      | test.t1 | check | status   | OK       |
      		 
      +---------+-------+----------+----------+
      		 
      1 row in set (0.005 sec)

      Which makes it fairly useless.

      And finally, the error log gets a different strange-looking warning instead:

      2019-07-28  0:57:51 140189814937344 [Warning] InnoDB: Cannot add field `c08` in table `test`.`t1` because after adding it, the row size is 2484 which is greater than maximum allowed size (1982) for a record on index leaf page.

      Attachments

        Issue Links

          blocks

          New Feature - A new feature of the product, which has yet to be developed. MDEV-20400 Implement a way to query an InnoDB table max row size

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-20949 Stop performing unnecessary maximum row size check for DML

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-19292 "Row size too large" error when creating table with lots columns when row format is DYNAMIC or COMPRESSED

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. MDEV-20000 Consider adopting innodb.innodb_pagesize_max_recordsize from MySQL

          • Major - Major loss of function.
          • Open

          New Feature - A new feature of the product, which has yet to be developed. MDEV-20400 Implement a way to query an InnoDB table max row size

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-20832 Don't print "row size too large" warnings in error log if innodb_strict_mode=OFF and log_warnings<=2

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21261 When performing instant add column, InnoDB ignores innodb_strict_mode for "row size too large" check

          • Major - Major loss of function.
          • Confirmed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21624 Unique index length is able to exceed max key length

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21748 ASAN use-after-poison in PageBulk::insertPage on table rebuild

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. MDEV-23521 Implement an InnoDB row format that can use overflow pages for smaller columns

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Task - A task that needs to be done. MDEV-16969 Fix error message as promised in upstream Bug #69336

          • Major - Major loss of function.
          • Open

          New Feature - A new feature of the product, which has yet to be developed. MDEV-20400 Implement a way to query an InnoDB table max row size

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-20786 MariaDB server writes warnings into errorlog although 'log_warnings=0'

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21429 TRUNCATE and OPTIMIZE are being refused due to "row size too large"

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

          Bug - A problem which impairs or prevents the functions of the product. MDEV-22585 Incorrect note being written to the error log when CREATE and ALTER fail due to Row Size Too Large and in all cases for TRUNCATE and OPTIMIZE TABLE.

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Activity

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            View 7 older comments
            GeoffMontee Geoff Montee (Inactive) added a comment -

            Also if we decide to continue having these warnings in the error log, could we at least only have them logged if innodb_strict_mode=ON?

            Another option is that if innodb_strict_mode=OFF is set, then the logging behavior can be based on log_warnings, as requested in MDEV-20832.

            GeoffMontee Geoff Montee (Inactive) added a comment - Also if we decide to continue having these warnings in the error log, could we at least only have them logged if innodb_strict_mode=ON? Another option is that if innodb_strict_mode =OFF is set, then the logging behavior can be based on log_warnings , as requested in MDEV-20832 .
            marko Marko Mäkelä added a comment -

            Some of my comments related to the MDEV-20949 fix should be helpful for fixing this.

            marko Marko Mäkelä added a comment - Some of my comments related to the MDEV-20949 fix should be helpful for fixing this.
            marko Marko Mäkelä added a comment -

            As demonstrated in MDEV-21748, in MariaDB 10.3 the function instant_alter_column_possible() is computing max_size in the wrong way, not taking blob_prefix correctly into account. This will unnecessarily prevent instant ADD COLUMN operations.

            marko Marko Mäkelä added a comment - As demonstrated in MDEV-21748 , in MariaDB 10.3 the function instant_alter_column_possible() is computing max_size in the wrong way, not taking blob_prefix correctly into account. This will unnecessarily prevent instant ADD COLUMN operations.
            thiru Thirunarayanan Balathandayuthapani added a comment -

            Patch is in bb-10.3-MDEV-20194

            thiru Thirunarayanan Balathandayuthapani added a comment - Patch is in bb-10.3- MDEV-20194
            marko Marko Mäkelä added a comment -

            Thank you. I spotted a possible off-by-one error for ROW_FORMAT=REDUNDANT node pointer records. Otherwise, it looks OK to me.

            marko Marko Mäkelä added a comment - Thank you. I spotted a possible off-by-one error for ROW_FORMAT=REDUNDANT node pointer records. Otherwise, it looks OK to me.

            People

              thiru Thirunarayanan Balathandayuthapani
              elenst Elena Stepanova
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              2 Vote for this issue
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                Resolved:

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