| Bug #56439 | Call chk_key() upon any DDL operations | ||
|---|---|---|---|
| Submitted: | 1 Sep 2010 9:09 | ||
| Reporter: | Mikiya Okuno | Email Updates: | |
| Status: | Verified | Impact on me: | |
| Category: | MySQL Server: MyISAM storage engine | Severity: | S4 (Feature request) |
| Version: | 5.1 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
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Description: When we use MyISAM, we should firstly initialize index statistics using ANALYZE TABLE after adding index. Unless executing ANALYZE TABLE, index statistics isn't updated upon DML operations. How to repeat: mysql> create table t (a int, index(a)) engine myisam; Query OK, 0 rows affected (0.10 sec) mysql> insert into t values(1),(2),(3); Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> show index in t\G *************************** 1. row *************************** Table: t Non_unique: 1 Key_name: a Seq_in_index: 1 Column_name: a Collation: A Cardinality: NULL Sub_part: NULL Packed: NULL Null: YES Index_type: BTREE Comment: 1 row in set (0.00 sec) Like this, cardinality field is firstly NULL. It's enabled after issuing ANALYZE/REPAIR/CHECK TABLE statements. Suggested fix: Call chk_key() after every DDL statement operations.