> It's locked into EXCLUSIVE mode if it was in EXCLUSIVE mode when you switched to WAL. But > there's nothing requiring it.
I was not referring to the locking_mode, I was writing about the lock itself over the database (iNode structure). On QNX the exclusive locking_mode it is required, because it seems that shared memory is not working properly. The entry point when enabling WAL: JOURNALMODE_WAL will be enabled (a trace added by me) LOCK 11 SHARED was NONE(NONE,0) pid=229454 tid=20 (unix) fcntl pid=229454 tid=20 11 SETLK RDLCK 1073741824 1 125195676 0 fcntl pid=229454 tid=20 11 SETLK RDLCK 1073741826 510 125195676 0 fcntl pid=229454 tid=20 11 SETLK UNLCK 1073741824 1 125195676 0 LOCK 11 SHARED ok (unix) READ 11 16 24 0 LOCK 11 RESERVED was SHARED(SHARED,1) pid=229454 tid=20 (unix) fcntl pid=229454 tid=20 11 SETLK WRLCK 1073741825 1 125195740 0 LOCK 11 RESERVED ok (unix) LOCK 11 EXCLUSIVE was RESERVED(RESERVED,1) pid=229454 tid=20 (unix) fcntl pid=229454 tid=20 11 SETLK WRLCK 1073741824 1 125195708 0 fcntl pid=229454 tid=20 11 SETLK WRLCK 1073741826 510 125195708 0 LOCK 11 EXCLUSIVE ok (unix) TRANSACTION 139542152 OPENX 12 /mnt/share/testApp/myDB.nal 0402 fcntl unknown pid=229454 tid=20 12 1 0 fcntl unknown pid=229454 tid=20 12 2 0 OPEN 12 /mnt/share/testApp/myDB.nal WRITE 12 512 0 0 WRITE 12 4 512 0 WRITE 12 65536 516 0 WRITE 12 4 66052 0 JOURNAL 139542152 page 1 needSync=1 hash(00000000) Filename: /mnt/share/testApp/myDB.db State: WRITER_CACHEMOD errCode=0 Lock: EXCLUSIVE Locking mode: locking_mode=exclusive Journal mode: journal_mode=wal Backing store: tempFile=0 memDb=0 useJournal=1 Journal: journalOff=66056 journalHdr=0 Size: dbsize=35 dbOrigSize=35 dbFileSize=35 DATABASE SYNC: File=/mnt/share/testApp/myDB.db zMaster= nSize=35 READ 12 0 66560 0 SYNC journal of 139542152 SYNC 12 DIRSYNC /mnt/share/testApp/myDB.nal (have_fullfsync=0 fullsync=0) fcntl unknown pid=229454 tid=20 13 1 0 fcntl unknown pid=229454 tid=20 13 2 0 OPENDIR 13 /mnt/share/nav WRITE 12 12 0 0 SYNC journal of 139542152 SYNC 12 READ 11 4 24 0 WRITE 11 65536 0 0 STORE 139542152 page 1 hash(00000000) SYNC 11 COMMIT 139542152 CLOSE -1 So far no UNLOCK... it continues opening four more connections to same db: OPENX 12 /mnt/share/testApp/myDB.db 02 fcntl unknown pid=229454 tid=20 12 1 0 fcntl unknown pid=229454 tid=20 12 2 0 OPEN 12 /mnt/share/testApp/myDB.db OPEN 139532984 /mnt/share/testApp/myDB.db OPEN 139506232 /mnt/share/testApp/myDB.db OPENX 13 /mnt/share/testApp/myDB.db 02 fcntl unknown pid=229454 tid=20 13 1 0 fcntl unknown pid=229454 tid=20 13 2 0 OPEN 13 /mnt/share/testApp/myDB.db OPEN 139543832 /mnt/share/testApp/myDB.db OPEN 139505000 /mnt/share/testApp/myDB.db OPENX 14 /mnt/share/testApp/myDB.db 02 fcntl unknown pid=229454 tid=20 14 1 0 fcntl unknown pid=229454 tid=20 14 2 0 OPEN 14 /mnt/share/testApp/myDB.db OPEN 139531896 /mnt/share/testApp/myDB.db OPEN 139524696 /mnt/share/testApp/myDB.db OPENX 15 /mnt/share/testApp/myDB.db 02 fcntl unknown pid=229454 tid=20 15 1 0 fcntl unknown pid=229454 tid=20 15 2 0 OPEN 15 /mnt/share/testApp/myDB.db OPEN 139501056 /mnt/share/testApp/myDB.db OPEN 139501688 /mnt/share/testApp/myDB.db Next read requests - SHARED locks will fail: LOCK 12 SHARED was NONE(EXCLUSIVE,1) pid=229454 tid=16 (unix) LOCK 12 SHARED failed (unix) UNLOCK 12 0 was 0(4,1) pid=229454 tid=16 (unix) ROLLBACK 139532984 LOCK 12 SHARED was NONE(EXCLUSIVE,1) pid=229454 tid=20 (unix) LOCK 12 SHARED failed (unix) UNLOCK 12 0 was 0(4,1) pid=229454 tid=20 (unix) ROLLBACK 139532984 LOCK 12 SHARED was NONE(EXCLUSIVE,1) pid=229454 tid=20 (unix) LOCK 12 SHARED failed (unix) UNLOCK 12 0 was 0(4,1) pid=229454 tid=20 (unix) ROLLBACK 139532984 LOCK 12 SHARED was NONE(EXCLUSIVE,1) pid=229454 tid=20 (unix) LOCK 12 SHARED failed (unix) UNLOCK 12 0 was 0(4,1) pid=229454 tid=20 (unix) ROLLBACK 139532984 LOCK 12 SHARED was NONE(EXCLUSIVE,1) pid=229454 tid=20 (unix) LOCK 12 SHARED failed (unix) UNLOCK 12 0 was 0(4,1) pid=229454 tid=20 (unix) ROLLBACK 139532984 So, the same process, it is clear that no other process/thread is accessing the database. Why the EXCLUSIVE lock acquired during the WAL enabling is not released? Regards, Sandu Buraga _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
