Re: [ADMIN] Stuck Spinlock Error Message
Ludwig Isaac Lim [EMAIL PROTECTED] writes: I'm guessing that the spinlock error occurs after there are around hundreds (or thousands) of queued postmaster processes. Thousands? How large is your max_connections parameter, anyway (and do you really have big enough iron to support it)? The stuck spinlock error implies that some work that should have taken a fraction of a microsecond (namely the time to check and update the internal state of an LWLock structure) took upwards of a minute. Since the process holding the spinlock could lose the CPU, it's certainly physically possible for the actual duration of holding the spinlock to be much more than a microsecond. But the odds of losing the CPU while holding the spinlock are not large, since it's held for just a small number of instructions. And to get an actual stuck spinlock failure would imply that the holding process didn't get scheduled again for more than a minute (while some other process that wanted the spinlock *did* get scheduled again --- repeatedly). I suppose this is possible if your machine is sufficiently badly overloaded. regards, tom lane ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [ADMIN] Stuck Spinlock Error Message
Hi: --- Tom Lane [EMAIL PROTECTED] wrote: What can cause a stuck spinlock? In theory, that shouldn't ever happen. Can you reproduce it? regards, tom lane I could not reproduce it, but I'll describe how error happen. I have a program that read a file large file which 20,000 records and spawn a process that execute a PLPGSQL stored function based on the content of the file. The following is a table of the SQL statement generated: process 1 SELECT f1(120, 123.3); process 2 SELECT f1(120, 53.3); process 3 SELECT f1(120, 31.3); .. .. process n SELECT f1(120,2.3); the function f1 is basically defined as CREATE OR REPLACE FUNCTION f1(integer, float8) RETURN INTEGER AS' DECLARE -- some variable declaration BEGIN -- Lock the table based on the first parameter -- of the stored function (use record level lock) SELECT * FROM t1 WHERE field1 = $1 FOR UPDATE; --a batch of SQL statements here -- END;' LANGUAGE 'plpgsql'; As you noticed the the first parameter of the called function is the same (Due to bug on our program). Since it performs a record level lock on the record, the processes will queue (i.e. will execute if only a process relinquish its lock). I'm guessing that the there was just to many postmaster process trying to concurrently trying to access the same record being lock by a record-lock. When I execute the top command in linux there are a lot of postmaster process in the process list Is the spinlock error possible given that scenario? Is this error related to the following error messages: fatal 2: cannot write block 3 of 16556/148333 blind : too many open files in sysytem. Note : I was able to correct the above error messages by increasing the file-max parameter in the sysctl.conf. I'm guessing that the spinlock error occurs after there are around hundreds (or thousands) of queued postmaster processes. best regards, ludwig __ Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. http://search.yahoo.com ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
[ADMIN] Stuck Spinlock Error Message
Hi: I notice the following error message in my postgresql log file: FATAL : s_lock (0x401db020) at lwlock.c Stuck spinlock. Aborting Version of my postgresql : PostgreSQL 7.2.3 on i686-pc-linux-gnu compiled by GCC 2.96 Operating System : RedHat 7.1 What can cause a stuck spinlock? Thanks in advance, ludwig lim __ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
Re: [ADMIN] Stuck Spinlock Error Message
Ludwig Isaac Lim [EMAIL PROTECTED] writes: What can cause a stuck spinlock? In theory, that shouldn't ever happen. Can you reproduce it? regards, tom lane ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
