-=| Dmitry Yemanov, 14.11.2011 23:42:53 +0400 |=-
> 14.11.2011 23:15, Damyan Ivanov wrote:
>
> > # session 1
> > $ FIREBIRD=. FIREBIRD_LOCK=. isql-fb dbd-firebird-test.fdb
> > Database: dbd-firebird-test.fdb
> > SQL>
> >
> > # session 2, from another terminal, running in the same working
> > # directory
> > FIREBIRD=. FIREBIRD_LOCK=. isql-fb dbd-firebird-test.fdb
> > # hangs
>
> Do both terminals run with the same Linux user credentials?
Yes. The same setup works on several other architectures.
> Is there anything interesting in firebird.log?
There is no firebird.log file in the current directory. Perhaps
I missed an additional environment variable that needs to be set for
embedded (the system-wide firebird log directory is not writable by
the user).
> > Attaching gdb to the second session's isql and requesting a backtrace
> > gives the following:
>
> The second connection waits for the first one to downgrade its database
> lock, but its request gets ignored.
>
> A lock print output (with the -a switch) could be useful here.
Here it is. This is after (1) creating the database in the first
session and (2) attempting to attach to the freshly created database
in another session (same user, hanging).
$ FIREBIRD=. FIREBIRD_LOCK=. /usr/sbin/fb_lock_print -d test.fdb
LOCK_HEADER BLOCK
Version: 17, Active owner: 0, Length: 1048576, Used: 23896
Flags: 0x0001
Enqs: 79, Converts: 13, Rejects: 56, Blocks: 0
Deadlock scans: 0, Deadlocks: 0, Scan interval: 10
Acquires: 237, Acquire blocks: 0, Spin count: 0
Mutex wait: 0.0%
Hash slots: 1009, Hash lengths (min/avg/max): 0/ 0/ 3
Remove node: 0, Insert queue: 0, Insert prior: 0
Owners (2): forward: 20872, backward: 23672
Free owners: *empty*
Free locks: *empty*
Free requests: *empty*
Lock Ordering: Enabled
OWNER BLOCK 20872
Owner id: 73448235728900, type: 1, pending: 0
Process id: 17101 (Alive), thread id: 1073877248
Flags: 0x10 sgnl
Requests (21): forward: 21040, backward: 23440
Blocks (1): forward: 21040, backward: 21040
OWNER BLOCK 23672
Owner id: 73761768341505, type: 1, pending: 23840
Process id: 17174 (Alive), thread id: 1073877248
Flags: 0x24 wait tout
Requests (1): forward: 23840, backward: 23840
Blocks: *empty*
Event log:
------------- end of output ---------------
If at this point the first isql is exited, it hangs and the lock table
dump is:
LOCK_HEADER BLOCK
Version: 17, Active owner: 0, Length: 1048576, Used: 27144
Flags: 0x0001
Enqs: 531, Converts: 16, Rejects: 450, Blocks: 0
Deadlock scans: 0, Deadlocks: 0, Scan interval: 10
Acquires: 1521, Acquire blocks: 1, Spin count: 0
Mutex wait: 0.1%
Hash slots: 1009, Hash lengths (min/avg/max): 0/ 0/ 3
Remove node: 0, Insert queue: 0, Insert prior: 0
Owners (1): forward: 23672, backward: 23672
Free owners (1): forward: 20872, backward: 20872
Free locks (2): forward: 21224, backward: 26840
Free requests (1): forward: 26784, backward: 26784
Lock Ordering: Enabled
OWNER BLOCK 23672
Owner id: 73761768341505, type: 1, pending: 0
Process id: 17174 (Alive), thread id: 1073877248
Flags: 0x08 wake
Requests (47): forward: 23840, backward: 27024
Blocks: *empty*
Event log:
DEL_OWNER: owner = 20872, lock = 20872, request = 0
------------- end of output ---------------
Hopefully this gives some clues.
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