https://www.sqlite.org/lockingv3.html
I have read through the attached link but what is outlined here doesn't seem to match with what I am seeing in a production SQLite setup we have. Specifically the writer starvation part of the document. We have a DB that is heavily read. Writes happen very infrequently. We were finding that writes were failing with "Database locked" (SQLITE_BUSY I believe) from time to time. To reproduce I execute continuous reads in a tight loop. Then I tried to execute a write operation (create table) and received database locked. After a bit of reading and troubleshooting I stumbled across the busy_timeout option (which defaults to 0). Prior to execute the create table statement I set PRAGMA busy_timeout=1000 (1 s) and the writes always succeeded. So since busy_timeout defaults to 0, all write attempts if a lock can't be obtained will return SQLITE_BUSY immediately. Where does the PENDING lock come into play here? I thought the PENDING was meant to be an intermediary step before EXCLUSIVE. Does the busy_timeout impact the writers attempt to obtain PENDING? Or does the busy_timeout trigger after X amount of ms between obtaining PENDING and trying to move to EXCLUSIVE? Thanks _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
