it's better to use a connection per thread... the connection resource isn't very big... even if you wrap the sqlite3_ calls... you'll need to wrap the entire lifetime of the statment... if you do a execute and then start stepping and getting values while another thread starts another statement... that's 3 individual locks, but it doesn't lock the context of the statement being used... it will lead to bizarre crashes in the database; similar to double-releasing memory or delayed reference of memory that has been released.
On Sun, Feb 8, 2015 at 3:00 AM, Dan Kennedy <danielk1...@gmail.com> wrote: > On 02/08/2015 04:30 PM, Neo Anderson wrote: > >> The doc says: >> >> Multi-thread. >> In this mode, SQLite can be safely used by multiple threads provided that >> no single database connection is used simultaneously in two or more >> threads. >> >> I have a scenario that every sqlite3_calls around a single database >> connection is protected by a recursive mutex, but I have very strange >> runtime error in sqlite3.c and each time the error occurs at a different >> place. >> >> Does this mean the following statement is true: >> >> In muti-thead mode, a single database connection cannot be shared among >> threads even if any activity around the connection is protected by a mutex. >> > > Not true. > > The only difference between multi-threaded and serialized mode is that, > internally, every sqlite3_xxx() API call grabs a recursive mutex to prevent > two threads from simultaneously accessing the database handle structure. > i.e. the same thing your code is doing externally. > > Note that calls on statement handles (i.e. sqlite3_step(), > sqlite3_column_text() etc.) count as calls on the database handle that > created them. So you need to protect them with the same mutex. > > Does the application work if you configure SQLite to serialized mode? > > Dan. > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
