0
votes
0answers
33 views

MySql - multi-column index using only null values from one column

I have a Innodb table with a index that looks at 3 columns. ColA is integer and always has a value. ColB is varchar and always has a value. ColC is datetime and sometimes has a value (NULL). My ...
0
votes
0answers
59 views

Understanding how MySQL indexes work

I'm reading this page but I can't get past the following parts: When all tables are processed, MySQL outputs the selected columns and backtracks through the table list until a table is found ...
0
votes
1answer
50 views

query not taking index into account

EXPLAIN EXTENDED SELECT SQL_CALC_FOUND_ROWS SQL_NO_CACHE g.*, u.user_id FROM geotable g JOIN userstable u ON g.uid = u.uid -- corners selection: WHERE (lat BETWEEN ? and ? AND lon ...
1
vote
0answers
133 views

Fulltext search returning too many rows

Server: MySQL 5.1.66-0+squeeze1 My problem: I have two databases with the same tables. One is for the testing environment and one for production. When I perform a MATCH AGAINST on the prodution ...
3
votes
1answer
82 views

How can I get this query to use it's index?

Queries matching this query below shows up in the slow log (with different contentVersionId & modifiedDateTime). As I don't really know what I'm doing I tried adding indexes to all columns in ...
1
vote
0answers
36 views

How does MySQL 5.1 use indexes?

I've read the docs for MySQL v5.1.x on how about the indexes are used, but I'm not sure I understood it properly. Suppose having the following MySQL table: CREATE TABLE IF NOT EXISTS ...