[MDEV-782] LP:424553 - No way to limit temporary table size when Aria tables are in use Created: 2009-09-04  Updated: 2013-05-23  Resolved: 2013-05-23

Status: Closed
Project: MariaDB Server
Component/s: None
Fix Version/s: 10.0.4

Type: Task Priority: Minor
Reporter: Sergei Petrunia Assignee: Sergei Petrunia
Resolution: Won't Fix Votes: 0
Labels: Launchpad

Attachments: XML File LPexportBug424553.xml    

 Description   

I've hit this while merging this testcase from mysql-5.1/mysql-test/insert_select.test:

CREATE TABLE t1(a INT);

  1. To force MyISAM temp. table in the following INSERT ... SELECT.
    SET max_heap_table_size = 16384;
  2. To overflow the temp. table.
    SET @old_myisam_data_pointer_size = @@myisam_data_pointer_size;
    SET GLOBAL myisam_data_pointer_size = 2;

INSERT INTO t1 VALUES (1), (2), (3), (4), (5);

--error ER_RECORD_FILE_FULL,ER_RECORD_FILE_FULL
INSERT IGNORE INTO t1 SELECT t1.a FROM t1,t1 t2,t1 t3,t1 t4,t1 t5,t1 t6,t1 t7;

The problems are that

  • Aria engine doesn't have an analog of myisam_data_pointer_size, consequently the insert will not fail and we can't run the testcase.
  • Albeit there is a #define USE_MARIA_FOR_TMP_TABLES, once you have a binary there is no straightforward way to tell from SQL whether it will use maria or myisam for temporary tables.

 Comments   
Comment by Sergei Petrunia [ 2009-09-04 ]

Re: No way to limit temporary table size when maria tables are in use
Will add a server variable.

Comment by Sergei Petrunia [ 2009-12-01 ]

Re: No way to limit temporary table size when maria tables are in use
I think 5.1 tag should be removed and priority reduced.

Other than the mentioned testcase (which we can live without), I have never saw anything or anybody to use @@myisam_data_pointer_size value to limit temporary table size. If there is a real need to set such limit, we should add a separate variable, e.g. @@disk_temp_table_size.

With regards to inability to check the USE_MARIA_FOR_TMP_TABLES setting from SQL, that doesn't seem to be high priority (haven't seen anybody to build MariaDB with MyISAM temp.tables for a while, there are no known issues with MyISAM vs Maria temp.tables, etc.)

Comment by Sergei Petrunia [ 2009-12-01 ]

Re: No way to limit temporary table size when maria tables are in use
Changed tags and priority accordingly.

Comment by Rasmus Johansson (Inactive) [ 2011-03-01 ]

Launchpad bug id: 424553

Comment by Sergei Petrunia [ 2013-05-23 ]

Closing as "Wont' fix" because currently, there are no plans to fix it. Feel free to re-open if this issue becomes relevant.

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