----- Original Message ---- From: Christian Smith <[EMAIL PROTECTED]> To: sqlite-users@sqlite.org Sent: Thursday, November 9, 2006 8:38:51 AM Subject: Re: [sqlite] indexes in memory
> chetana bhargav uttered: > > Hi, > > > I have a question regrading indexes, > > > > When I open a connection, > > > > Will indexes be loaded into memory. If one of the tables in the DB, the > > connection for which I have opened, has an index. > > If, so is there any way to selectively load/unload that from memory. > > > Indexes will be loaded into the cache as needed. The whole SQLite database > is page based, and the cache caches the pages. The tables and indexes are > implemented as page based btrees, with nodes represented by pages. > > The cache is unaware of the higher level structure of the btrees, and > there is no way to selectively bring load/unload tables or indexes from > memory. The page cache will manage itself on an LRU basis. > > > ... > > Chetana. > Christian I found that when opening your connection, if you're about to do a lot of operations it can be worth doing a "SELECT keyname FROM ... "over the whole data to prepopulate the cache with the index data. Even on pretty large datasets this only takes a few seconds and the following operations will be much faster (and the overall time to complete the batch is much smaller). Nicolas
