| 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 | |
Portions of this website are copyright © 2001, 2002 The PHP Group
Page generated in 0.049 sec. using MySQL 8.0.36-u4-cloud
Timestamp references displayed by the system are UTC.
Content reproduced on this site is the property of the
respective copyright holders.
It is not reviewed in advance
by Oracle and does not necessarily represent the opinion of
Oracle or any other party.
© 2024, Oracle Corporation and/or its affiliates
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.