On 4/28/16, Dominique Devienne <ddevienne at gmail.com> wrote: > > Richard, is STAT3 or STAT4 required for > https://www.sqlite.org/optoverview.html#skipscan ? > Or essential for skip-scan to bring the most benefit? --DD
No. But sqlite_stat1 data is. Skip-scan is only attempted if there are an average of 18 or more repeats of the skipped column(s) - a number we came up with by doing actual queries to see where the pay-off point started. Without sqlite_stat1 data, SQLite will assume that there are only 10 repeats of each entry, at most, so without sqlite_stat1 data, skip-scan will never be used. -- D. Richard Hipp drh at sqlite.org
