InnoDB: Number of pending reads 128, pending pread calls 0
InnoDB: Error: InnoDB has waited for 50 seconds for pending
InnoDB: reads to the buffer pool to be finished.
What does this mean? Well searching yahoo search I couldn't find anything other then pointers to source code where this message generated. I assumed it was a disk problem because performance was super crappy.
My disk monitoring software which probes MegaRaidCli didn't report a failed disk. Linux didn't report a failed disk or any errors. So, what is happening? Was I wrong?
Well, in fact it was a failed disk, but not in a state that could be classified as failed by the controller or any other component including the OS. With the help of my bud we found that a disk in the array was in a critical state-the disk itself just had a bunch of sector errors, yet the controller, os, everything would not mark it as dead - so the end result was to remove the drive and swap it with another.
So in essence this message means something is wrong with your disks and or filesystem.
See how SMART can be useful to you http://www.linuxjournal.com/article/6983
ReplyDeleteI found myself in a situation with this error after a user tried to query a table while it was being repaired and mysql crashed itself because of a semaphore timeout.
ReplyDeleteIn an act of desperation I was able to clear this with a reboot of the server. I'd be curious to see if switching to single user mode remounting the /usr filesystem wold be sufficient.
I had the same thing happen, but restarting didn't work. I had to delete all my ibdata files and re-create them. This is easy, you just stop, delete, start. Of course, you lose all your data, but them's the breaks. Hopefully you've got backups.
ReplyDelete