On Aug 28, 2008, at 3:19 AM, [EMAIL PROTECTED] wrote: >> Is there a performance hit assosiated with manifest typing? > > I'm not sure about performance, but I assume that static typing > might reduce memory usage (especially with small caches). Internally > every type in sqlite is stored in structure that takes 64 bytes > (little more on 64 bit systems). Different structure for every type > or even union would make the size smaller. >
The structure that holds a variable in SQLite is 40 bytes on a 32-bit system and 56 bytes on 64-bit. The number of such structures required for an SQLite statement depends on the complexity of the statement, but averages around 13. Assuming the same structure in a rigidly typed system requires 8 bytes (the size of a 64-bit integer) then your total savings will be about 624 bytes on a 64-bit system - less on a 32-bit system. You can save more memory by reducing the size of your disk cache from 2000 to 1999 pages. Note also that the extra code complexity required to support a rigid type system would likely swell the size of the library by several hundred kilobytes. So you would be trading perhaps 250KB of code space for a heap space savings of less than 1KB. D. Richard Hipp [EMAIL PROTECTED] _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
