If you remove a busy check, does it output any statements?
Do you have any custom functions/operations running so they could block
sqlite in creating new statement?
2013/7/17 Loren Keagle <loren.kea...@braemarllc.com>
> Hi everyone,
>
> I have an interesting locking problem that I'm wondering if someone can
> help with some insight.
>
> I have a master database with some metadata, and several sub-databases to
> store logging events. I have one reader object and one writer object that
> attach to the sub-databases and encapsulate the read/write operations
> respectively.
>
> I've found a very unexpected locking behavior with the attached databases
> and exclusive transactions. One of my unit tests does the following:
>
> Begin EXCLUSIVE TRANSACTION;
> insert several rows of data;
> Commit transaction;
>
> Prepare query statement;
> Iterate through one or more rows;
> Reset statement;
>
> Attempt to begin transaction; <--- SQLITE_BUSY!!!!
> Would like to write more here, but can't unless I close/open the
> connection;
>
> I can't seem to figure out any reason why I can't create a new exclusive
> transaction here, and I feel it must have to do with the fact that I have
> attached to sub-databases (possibly the same sub-database) with my
> reader/writer objects. This is single threaded and only database connection
> (with attach/detach logic).
> I have verified that all statements prepared by the connection are
> properly reset - this is handled by my C++ wrappers, and any errors will
> throw an exception. I even iterated through all of the current statements
> with the following code immediately before my transaction failure, with no
> results:
>
> sqlite3_stmt *stmt = NULL;
> while ((stmt = sqlite3_next_stmt(db, stmt)) != NULL)
> {
> if (sqlite3_stmt_busy(stmt))
> {
> const char* sql = sqlite3_sql(stmt);
> std::cout << sql << "\r\n";
> }
> }
>
> Can anyone think of a reason why attached databases would prevent entering
> a second transaction? BTW, it doesn't seem to work with immediate
> transactions either. If I remove the query, everything works fine.
>
> Thanks!
>
>
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