"Mina R Waheeb" <[EMAIL PROTECTED]> wrote: > Hi, > I have few questions regarding the limitation of multiple databases with > SQLite. > > I have a large number of SQLite DB files with the same structure i > need to query them all (looking for speed), I have tried ATTACH method > and its working fine but there is a limitation on the number of > attached files > > in sqlitelimit.h > /* > ** The maximum number of attached databases. This must be at least 2 > ** in order to support the main database file (0) and the file used to > ** hold temporary tables (1). And it must be less than 32 because > ** we use a bitmask of databases with a u32 in places (for example > ** the Parse.cookieMask field). > */ > > - Is there is any way or patch to increase the number of attached > files more than 32?
You could change the unsigned 32-bit integer used for the mask into an unsigned 64-bit integer. This will be tricky, though, as a lot of things will need to change. > > - is SQLite open FD to each attached database or open it on request? Actually, 3 file descriptors per attached database. > > - Once the SQLite library loaded in memory, How much the new > connection cost of the system resources mainly in the memory? That depends on the size of the database schema. > > - If the schema is standard (Will not change), Is there is anyway just > switch between the FD to avoid reparse on startup? sorry maybe this is > a stupid question but i dunno much about SQLite internals. > No. -- D. Richard Hipp <[EMAIL PROTECTED]> ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
