sqlservr.exe suddenly consuming more memory

Clarifications

Unless you tell SQL server exactly how much memory to take up, it will take what it wants. If you don't like what it is doing, then change in the SQL server properties how much memory it is allowed.

Edit to add: Be careful!! You could cause major slowdowns etc. by yanking it's memory away...

where you posted you question as well........

Although Tony and cmiller are correct, you can set it to consume less memory..I'm a fan of of fixing the problem if possible.

Is it actually causing a problem? I know that sounds stupid, but I have a DB which is not optomised very well (its on the "to do" list) and it spikes with very heavy memory usage..and will sometimes stay like that for a bit. However, it doesn't really cause any problems as its not a heaily used server.

Has anything been changed? New queries added, new application hooked to it, new columns on a table which may effect an index ect?

Any time I've ever bothered to do any investigation, its usually been down a to a poorly written query along with a fragmented index.

Is there a lot of data entry on indexed columns? Are the indexes maintained frequently?