MySQL Forums
Forum List  »  Quality Assurance

merge table - index cardinality
Posted by: d batz
Date: November 23, 2011 01:02AM

Hi MySQL community,

I need your help or some few advice. This is my first post in MySQL forum.
I made some changes on our database and i created a new merge table.
I noticed some weird numbers of Index on Merge table.

Example:
I have 20 tables complete with indexes.

Each table contains:
id1 BTREE CARDINALITY XXXXX
id2 BTREE CARDINALITY XXXXX
id3 BTREE CARDINALITY XXXXX
cardinality is good in each table.... the usual.


The "Merge table" contains:
id1 BTREE CARDINALITY 71 <--- huh??
id2 BTREE CARDINALITY 26 <--- huh??
id3 BTREE CARDINALITY 0 <--- huh??

The merge table is pretty NORMAL TO USE (columns and index declaration are ok... i assumed ). When I look at the index numbers is weird. I dunno where that numbers are from....
or is there something i lack ??????? XDDDD

i did some few tests, querying the merge bale. Sometimes fast, sometimes slow... .

BTW all total records around 1,500,000. When i target id1 and id2..... I hit 1 second more or less.

Options: ReplyQuote


Subject
Views
Written By
Posted
merge table - index cardinality
2222
November 23, 2011 01:02AM
977
November 23, 2011 03:13AM


Sorry, you can't reply to this topic. It has been closed.

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.