Re[2]: Slow Queries Log and Index-less queries
Thanks Alexey, This is enough explanation for me ;) Cheers, HMax AP> I have a question regarding the slow queries log, and queries not using index. AP> I have a small table, with say 10 entries, like that : AP> ID | Element AP> - AP> 1 | One AP> 2 | Two AP> 3 | Three AP> 4 | Four AP> 5 | Five AP> 6 | Six AP> 7 | Seven AP> 8 | Eight AP> 9 | Nine AP> 10 | Ten AP> I want to get all those entries: AP> SELECT ID, Element FROM tblentries; AP> The problem is that this query, even if very fast, is logged in the slow query log because it does not use index (I AP> activated this option in the slow query log). Woudln't it be better if such queries would be logged only in case there AP> is a WHERE, ORDER or GROUP/HAVING clause ? AP> AP> Slow query log, especially with long-long-format turned on, isn't made for manual browsing anyway. AP> You'll have to use mysqldumpslow or some custom-made script to analyze it. AP> Queries that don't have 'where' are easy to filter then. AP> AP> Also, is it better to do : AP> SELECT ID, Element FROM tblentries; AP> or AP> SELECT ID, Element FROM tblentries WHERE ID > 0; AP> (In this last case, it won't be logged in the slow query log beause it uses an index...) AP> AP> It won't be logged if it actually will use index. In your example it won't use index, full table scan will be AP> used instead, because query optimizer is able to determine that all records match where condition. AP> AP> AP> -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Slow Queries Log and Index-less queries
> > > I have a question regarding the slow queries log, and queries not using > index. > > I have a small table, with say 10 entries, like that : > ID | Element > - > 1 | One > 2 | Two > 3 | Three > 4 | Four > 5 | Five > 6 | Six > 7 | Seven > 8 | Eight > 9 | Nine > 10 | Ten > > I want to get all those entries: > SELECT ID, Element FROM tblentries; > > The problem is that this query, even if very fast, is logged in the slow > query log because it does not use index (I > activated this option in the slow query log). Woudln't it be better if > such queries would be logged only in case there > is a WHERE, ORDER or GROUP/HAVING clause ? Slow query log, especially with long-long-format turned on, isn't made for manual browsing anyway. You'll have to use mysqldumpslow or some custom-made script to analyze it. Queries that don't have 'where' are easy to filter then. Also, is it better to do : > SELECT ID, Element FROM tblentries; > or > SELECT ID, Element FROM tblentries WHERE ID > 0; > > (In this last case, it won't be logged in the slow query log beause it > uses an index...) It won't be logged if it actually will use index. In your example it won't use index, full table scan will be used instead, because query optimizer is able to determine that all records match where condition. > -- > Alexey Polyakov
Slow Queries Log and Index-less queries
Hey list, I have a question regarding the slow queries log, and queries not using index. I have a small table, with say 10 entries, like that : ID | Element - 1 | One 2 | Two 3 | Three 4 | Four 5 | Five 6 | Six 7 | Seven 8 | Eight 9 | Nine 10 | Ten I want to get all those entries: SELECT ID, Element FROM tblentries; The problem is that this query, even if very fast, is logged in the slow query log because it does not use index (I activated this option in the slow query log). Woudln't it be better if such queries would be logged only in case there is a WHERE, ORDER or GROUP/HAVING clause ? Also, is it better to do : SELECT ID, Element FROM tblentries; or SELECT ID, Element FROM tblentries WHERE ID > 0; (In this last case, it won't be logged in the slow query log beause it uses an index...) Thank you, HMax -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
