On Tue, Mar 31, 2015 at 8:58 AM, Kevin Viraud < kevin.vir...@rocket-internet.de> wrote:
> Touche ! Thanks a lot. > > Looking more at the data yes it goes very often to ELSE Clause. And > therefore reaching the MAX_CACHED_RES. > > In there anyway to increase that value ? > > Basically, I have several tables containing millions of rows and let say 5 > columns. Those five columns, depending of their combination give me a 6th > value. > We have complex patterns to match and using simple LIKE / EQUAL and so on > wouldn't be enough. This can be applied to N number of table so we > refactored this process into a function that we can use in the SELECT > statement, by giving only the 5 values each time. > > I wouldn't mind using a table and mapping it through a join if it were for > my own use. > But the final query has to be readable and usable for almost-non-initiated > SQL user... So using a function with encapsulated case when seemed to be a > good idea and so far worked nicely. > > But we might consider changing it if we have no other choice... > > Regards, > > Kevin > > Thoughts... Memoization: http://en.wikipedia.org/wiki/Memoization Rewrite the function in pl/perl and compare performance Hierarchy of CASE statements allowing you to reduce the number of possibilities in exchange for manually pre-processing the batches on a significantly less complicated condition probably using only 1 or 2 columns instead of all five. I'm not familiar with the caching constraint or the data so its hard to make more specific suggestions. David J.
