Hi List,
I have a performance problem I can't get solved.
I have 2 tables, called Updates (1 mln rows) and Data (5 mln rows).
Table Updates has 2 (non-unique) keys, defined as:
> Hash bigint(20) unsigned default NULL
> Year tinyint(4) NOT NULL default '0'
Table Data has the same 2 (non-unique) keys, defined as:
> Hash bigint(20) unsigned NOT NULL default '0'
> Year tinyint(4) NOT NULL default '0'
The final purpose is to insert and update Data with new / changed Updates.
Before doing so, i have a "simple" query, like:
Select Count(*) From Data Inner Join Updates ON Data.Hash = Updates.Hash AND
Data.Year = Updates.Year;
but this one takes more than 30 minutes.
Before running this query, I did: Analyze Table Updates, Data; to speed up acc.
the manual 7.2.3.
Does someone know how to increase the performance for this query ?
Below the results of the explain for this query.
TIA, regards Cor
myQuery id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Updates ALL Hash,Year
1003823
1 SIMPLE Data ref Hash,Year Hash 8 Updates.Hash 2 Using where
