On Oct 5, 2008, at 4:55 PM, yaroslavp wrote: > > Hi all, > > For testing purposes, I created a single row with a large blob > (hundreds of > megs) in my database. There is also an integer column. When I do an > update > on the integer, the query is very slow, and there's a lot of disk > activity.
SQLite updates an entire row at a time. So when you change the integer, it has to rewrite both the integer and the BLOB. SQLite has to do this because the fields of a row are of varying length. Integers, for example, are stored in between 1 and 9 bytes depending on their magnitude. If you change the value of an integer it might change the amount of storage it requires, which then requires rewriting everything that comes afterwards. It is recommended that large BLOBs be stored in a separate table with only an INTEGER PRIMARY KEY. D. Richard Hipp [EMAIL PROTECTED] _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
