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From:Devananda Date:October 5 2005 4:04pm
Subject:Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)
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Devananda wrote:
> One of our servers which is configured primarily for InnoDB has crashed 
> in the same fashion three times in the past 48 hours. I've been going 
> over the error log, and I would like to know if anyone else has seen 
> similar errors, or can give me some pointers to work out this problem.
> 
 > (truncated message)

After googling and searching the mysql list archive and forums, and 
finding other folks who ran into the "semaphore wait has lasted > 600 
seconds" error, I saw no consistency between what caused that error for 
the other people and for my server. I started checking the error log 
very closely, and came upon something that seems very odd to me; I am 
hoping someone else can explain this to me (maybe I'm making a silly 
mistake?).

I cut out the very last dump of InnoDB Monitor Output in the server.err 
file (just to make it easier to read and grep through). I pulled out all 
the transactions that have a "lock struct", and examined each. They are 
ALL inserts (large ones), but there are two things which seem wrong to 
me: there are 9 transactions with lock structs listed, even though there 
are only "8 queries inside InnoDB"; two of the locks are on the same table.

If the same table was locked by two threads at the same time, that would 
explain the crash (wouldn't it?), but how is that possible? I thought 
the express purpose of semaphores was to prevent that.

I'm hoping someone else can shed some light on this :) Thanks!

Best Regards,
Devananda vdv



Thread
crashes in InnoDB with MySQL 4.1.14Devananda5 Oct
  • Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Devananda5 Oct
Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Heikki Tuuri6 Oct
  • Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Devananda6 Oct
Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Heikki Tuuri6 Oct
  • Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Devananda6 Oct
Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Heikki Tuuri7 Oct
  • Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Devananda7 Oct
Re: crashes in InnoDB with MySQL 4.1.14 (semaphore wait timeout)Heikki Tuuri9 Oct