25 Oct
2013
25 Oct
'13
1:01 p.m.
Hi Timour, Me and Stephane were discussing a performance issue, and are wondering - why does the @@optimizer_search_depth has a value of 62? There is a vale of optimizer_search_depth=0 which tells the optimizer to chose depth automatically (exhaustive if less than 7 tables, greedy search if more than that). This value looks like it was intended to be the default. Yet, currently the default (in both MariaDB and MySQL) is 62, which tells the optimizer use the "new" (as in "new in 5.1") greedy search code, but sets the depth so high that it uses exhaustive search. Is there any reason behind this? BR Sergei -- Sergei Petrunia, Software Developer MariaDB | Skype: sergefp | Blog: http://s.petrunia.net/blog