Appreciate the reply. I just found it odd that busy_timeout is set to 0 (so fail immediately) considering the intermediary PENDING stage. That stage is essentially useless with the default busy timeout of 0 no?
I will read up on WAL. On Tue, Feb 28, 2017 at 4:22 PM, Simon Slavin <slav...@bigfraud.org> wrote: > > On 28 Feb 2017, at 6:39pm, Matthew Ceroni <matthewcer...@gmail.com> wrote: > > > 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. > > You need to set the busy timeout at every connection to the database, > including those which only read and never write. It’s common to see it > done immediately after the sqlite3_open() command. It is not stored in the > database and new connections to the database do not know what it was set to > before. > > If that doesn’t fix things, as a diagnostic measure, try setting > busy_timeout to 30 seconds instead of just 1 second. Learning whether this > does or does not fix the problem will tell you a lot about what’s going on. > > Are you using WAL mode ? If not, you should try it. Locking works > differently in WAL files, as described in > > <https://www.sqlite.org/wal.html> > > > 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? > > There are two kinds of locks: shared and exclusive. A pending lock means > you have shared, not exclusive, but that you want exclusive. > > timeout applies when obtaining both shared and exclusive locks. Actually, > hold on, I’m not sure about this. Better to try what I wrote already then > get an expert to explain things. > > Simon. > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
