The code I use can calculate data flow for sql queries (summing xRead iAmt in VFS) and I noticed that many variations of INSERT SELECT led to very big data flow (multiplication of the db size). I thought that such queries can be optimized if both tables are indexed accordingly and finally the following query
INSERT OR IGNORE INTO Table (Field) SELECT SomeOtherField FROM OtherTable ORDER BY SomeOtherField produced significant reduce in data flow. (Field Is indexed in Table). I don't think the difference is related to some caching since the variant without ORDER BY shows 50 MB data transfer for 17 MB base while adding ORDER BY reduces it to 1 MB (1:50 ratio so far). But my other query uses more complex schema (with LEFT JOIN and several fields (although indexed together)). The problem is I could not optimize the query to reduce the data flow in this case. Are there any specific requirements for the inserts like the first one? Couldn not to find information about this in the documentation. Thanks Max _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
