If the OP shows us the data base schema, and the select, then perhaps its performance could be enhanced by changing something. One thing which I sometimes do is "denormalize" a table by splitting it into two, or more, tables which are related via a shared UUID value. I put the often used columns in one and the lesser used columns in the other. That way, when I do a SELECT which only needs the columns in the first, I don't need to read the other table at all. In my case, this table was rarely updated. But updating it (changing column values and adding new rows) is a bit more difficult. Too bad that SQLite does not implement updatable views.
On Thu, Aug 6, 2015 at 10:08 AM, Stephan Beal <sgbeal at googlemail.com> wrote: > On Thu, Aug 6, 2015 at 4:54 PM, Wade, William <bill.wade at dnvgl.com> wrote: > > > I'm an SQLite novice, so if I'm wrong about this, I hope someone will > > correct me. > > > > The first query will be slower than later queries for the reason Simon > > mentioned. > > > Pedantically speaking, "will" is not quite right. That will _normally_ > apply, but depends on the whims (and memory pressure) of the OS. > > When this question/problem has come up before, some people have suggested > "coercing" the raw db file into the filesystem cache with something like: > > cat mydb > /dev/null > > (or whatever the equivalent is on Windows) > > which simply causes mydb to be read into the filesystem cache, > independently of sqlite (again, subject to the whims of the OS). > > -- > ----- stephan beal > http://wanderinghorse.net/home/stephan/ > http://gplus.to/sgbeal > "Freedom is sloppy. But since tyranny's the only guaranteed byproduct of > those who insist on a perfect world, freedom will have to do." -- Bigby > Wolf > _______________________________________________ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- Schrodinger's backup: The condition of any backup is unknown until a restore is attempted. Yoda of Borg, we are. Futile, resistance is, yes. Assimilated, you will be. He's about as useful as a wax frying pan. 10 to the 12th power microphones = 1 Megaphone Maranatha! <>< John McKown
