[MDEV-3818] Query against view over IS tables worse than equivalent query without view Created: 2012-10-25 Updated: 2012-12-18 Resolved: 2012-12-17 |
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| Status: | Closed |
| Project: | MariaDB Server |
| Component/s: | None |
| Affects Version/s: | 5.5.28 |
| Fix Version/s: | 5.5.29 |
| Type: | Bug | Priority: | Major |
| Reporter: | Georg Richter | Assignee: | Timour Katchaounov (Inactive) |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Environment: |
Linux x64 |
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| Description |
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A view which access an information schema table seems to use another plan, than the query in its extend explain output (it scan's all databases) CREATE VIEW v1 AS SELECT TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS; explain extended select column_name FROM v1 WHERE TABLE_SCHEMA="osm" AND TABLE_NAME="test"; extra: Using where; Open_frm_only; Scanned all databases show warnings; explain select `information_schema`.`COLUMNS`.`COLUMN_NAME` AS `COLUMN_NAME` from `INFORMATION_SCHEMA`.`COLUMNS` where ((`information_schema`.`COLUMNS`.`TABLE_SCHEMA` = 'osm') and (`information_schema`.`COLUMNS`.`TABLE_NAME` = 'test')); extra: Using where; Open_frm_only; Scanned 0 databases |
| Comments |
| Comment by Timour Katchaounov (Inactive) [ 2012-10-25 ] |
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The problem is present in MySQL 5.6.7 as well. |
| Comment by Timour Katchaounov (Inactive) [ 2012-12-17 ] |
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