[sqlite] Enable WAL on a QNX system

> If you want to have more than one connection to the database from within > the same process (but not multiple processes) and still use WAL without > shared-memory, using VFS "unix-excl" instead of the default might work. With the default VFS for QNX - "unix" the WAL did not worked, using

Re: [sqlite] Enable WAL on a QNX system

On 11/20/2013 12:20 AM, Sandu Buraga wrote: 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

Re: [sqlite] Enable WAL on a QNX system

> 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

Re: [sqlite] Enable WAL on a QNX system

On 19 Nov 2013, at 4:24pm, Sandu Buraga wrote: > I noticed that when PRAGMA main.journal_mode=WAL; statement is executed, > the database file is locked in EXCLUSIVE mode, It's locked into EXCLUSIVE mode if it was in EXCLUSIVE mode when you switched to WAL. But there's

Re: [sqlite] Enable WAL on a QNX system

> > I am starting to believe that WAL is not a viable choice on a QNXsystem. > > > All Blackberry phones and tables use it. It may be so, all Blackberry devices may be using WAL, but on my QNX system I just could not make it work. I haven't made a absolute statement, about SQLite and QNX, I just

Re: [sqlite] Enable WAL on a QNX system

On Thu, Nov 14, 2013 at 4:42 AM, Sandu Buraga wrote: > I am starting to believe that WAL is not a viable choice on a QNX system. > All Blackberry phones and tables use it. -- D. Richard Hipp d...@sqlite.org ___ sqlite-users

Re: [sqlite] Enable WAL on a QNX system

For a QNX system Richard suggested to set locking mode EXCLUSIVE before trying to set the WAL journal mode. When PRAGMA main.journal_mode=WAL is executed, the sqlite code checks whether EXCLUSIVE lock is enabled, or if shared memory is supported. The shared-memory implementation from sqlite is

Re: [sqlite] Enable WAL on a QNX system (Richard Hipp)

On 13 Nov 2013, at 4:04pm, Sandu Buraga wrote: > But, after I enable the WAL mode the > consequent transactions (in any other threads) will go in database lock. WAL mode is saved with the database. Once you have enabled WAL mode, that setting is stored with the

Re: [sqlite] Enable WAL on a QNX system (Richard Hipp)

Hi Richard, Yes, only one thread is working on the database first time. So even if I am opening more handles, I work only with one of the handles to run some PRAGMA statements and to check the structural integrity of database. If tables, or columns are missing I will run some DROP TABLE IF EXISTS

Re: [sqlite] Enable WAL on a QNX system (Richard Hipp)

unknown pid=233565 tid=20 17 1 0 > fcntl unknown pid=233565 tid=20 17 2 0 > OPENDIR 17 /mnt/share/testApp > WRITE 16 12 0 0 > SYNC journal of 139631856 > SYNC16 > READ11 4 24 0 > WRITE 11 65536 0 0 > STORE 139631856 page 1 hash() > SYNC11 > COMMIT 139631856 > CLOSE -1 > LOCK13 SHARED was NONE(EXCLUSIVE,1) pid=233565 tid=16 (unix) > LOCK13 SHARED failed (unix) > UNLOCK 13 0 was 0(4,1) pid=233565 tid=16 (unix) > ROLLBACK 139547936 > LOCK13 SHARED was NONE(EXCLUSIVE,1) pid=233565 tid=20 (unix) > LOCK13 SHARED failed (unix) > UNLOCK 13 0 was 0(4,1) pid=233565 tid=20 (unix) > ROLLBACK 139547936 > LOCK13 SHARED was NONE(EXCLUSIVE,1) pid=233565 tid=20 (unix) > LOCK13 SHARED failed (unix) > UNLOCK 13 0 was 0(4,1) pid=233565 tid=20 (unix) > ROLLBACK 139547936 > LOCK13 SHARED was NONE(EXCLUSIVE,1) pid=233565 tid=20 (unix) > LOCK13 SHARED failed (unix) > UNLOCK 13 0 was 0(4,1) pid=233565 tid=20 (unix) > ROLLBACK 139547936 > LOCK13 SHARED was NONE(EXCLUSIVE,1) pid=233565 tid=20 (unix) > LOCK13 SHARED failed (unix) > UNLOCK 13 0 was 0(4,1) pid=233565 tid=20 (unix) > ROLLBACK 139547936 > > > Regards, > Sandu Buraga > > > > Date: Thu, 31 Oct 2013 14:05:17 -0400 > From: Richard Hipp <d...@sqlite.org> > To: General Discussion of SQLite Database <sqlite-users@sqlite.org> > Subject: Re: [sqlite] Enable WAL on a QNX system > Message-ID: >

Re: [sqlite] Enable WAL on a QNX system (Richard Hipp)

On Tue, Nov 12, 2013 at 8:12 AM, Richard Hipp wrote: > > > > On Mon, Nov 11, 2013 at 12:33 PM, Sandu Buraga wrote: > >> Hi, >> >> I took your advice and now I am setting only once the journal_mode=WAL, >> also locking_mode=EXCLUSIVE and temp_store=MEMORY.

Re: [sqlite] Enable WAL on a QNX system (Richard Hipp)

On Mon, Nov 11, 2013 at 12:33 PM, Sandu Buraga wrote: > Hi, > > I took your advice and now I am setting only once the journal_mode=WAL, > also locking_mode=EXCLUSIVE and temp_store=MEMORY. But still it doesn't > work, and I get DB locks immediately. I enabled SQLite

Re: [sqlite] Enable WAL on a QNX system (Richard Hipp)

ite-users@sqlite.org> Subject: Re: [sqlite] Enable WAL on a QNX system Message-ID:

Re: [sqlite] Enable WAL on a QNX system

On Thu, Oct 31, 2013 at 9:56 AM, Sandu Buraga wrote: > Hi, > > I am using SQLite 3.7.9, and QNX 6.5.0 running on Intel x86 machine. I am > having a use-case with multiple readers threads and one writer thread, all > running in the same process. No other process is using

[sqlite] Enable WAL on a QNX system

Hi, I am using SQLite 3.7.9, and QNX 6.5.0 running on Intel x86 machine. I am having a use-case with multiple readers threads and one writer thread, all running in the same process. No other process is using the SQLite database file. I tried to enable WAL feature, but with no success so far.