Hi, We see random failure on our Windows build bot when it tries to open different working copies at the same time. This is a simple retry patch for that.
On IRC, Bert spoke out in favour of debugging and fixing sqlite itself - hence I won't commit the patch right now. However, I've also been unable to reproduce the problem under LINUX so far and can't really help with the effort. -- Stefan^2. [[[ Attempt to address the "unable to open database file" error we see at least on our test suite with multi-threaded SQLITE code. http://www.mail-archive.com/sqlite-users@sqlite.org/msg81284.html hints at a problem with temporary files used by SQLITE internally, i.e. the root cause lying in the SQLITE code itself. Hence, we add a workaround for now that simply retries the open() operation for a reasonable amount of time. * subversion/libsvn_subr/sqlite.c (BUSY_TIMEOUT): Document that we use this timeout for failing open() calls as well. (internal_open): Retry if we couldn't open the DB for some potentially transient reason. ]]] --- subversion/libsvn_subr/sqlite.c (revision 1555441) +++ subversion/libsvn_subr/sqlite.c (working copy) @@ -174,10 +174,11 @@ struct svn_sqlite__value_t } while (0) -/* Time (in milliseconds) to wait for sqlite locks before giving up. */ +/* Time (in milliseconds) to wait for sqlite locks before giving up. + We use the same timeout for handling other concurrency issues in + sqlite's open function. */ #define BUSY_TIMEOUT 10000 - /* Convenience wrapper around exec_sql2(). */ #define exec_sql(db, sql) exec_sql2((db), (sql), SQLITE_OK) @@ -838,6 +839,28 @@ internal_open(sqlite3 **db3, const char do this manually. */ /* ### SQLITE_CANTOPEN */ int err_code = sqlite3_open_v2(path, db3, flags, NULL); + + /* SQLITE seems to have race condition that prevent separate threads + from opening separate DBs at the same time. */ + if (err_code == SQLITE_CANTOPEN) + { + /* Retry for approx. 10 seconds while we get the standard "can't + open" error return. */ + apr_time_t start = apr_time_now(); + while ( (err_code == SQLITE_CANTOPEN) + && (apr_time_now() - start < BUSY_TIMEOUT * 1000)) + { + /* The db object is in an undefined state - clean it up. + We don't catch the error here, since we only care about the + open error at this point. */ + sqlite3_close(*db3); + + /* Retry. */ + err_code = sqlite3_open_v2(path, db3, flags, NULL); + } + } + + /* Now back to normal error handling. */ if (err_code != SQLITE_OK) { /* Save the error message before closing the SQLite handle. */
