We added 4 files to tempdb, due to Pagelatch_up being major wait
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Yet they do not appear to be used, and lots of Pagelatch_up: tempdb waits are still showing.
all 4 new files show 98% of free/available space, while the original 8 files are being used, at 50 and more percent, showing 20 or 30 % only free in them. Why are the new files not being used to relieve the Allocation Contention? Should we have rebooted the server?
Or
what else can we do to make tempdb start using the newly added files?
Likes to play Chess
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Adding files to tempdb for that wait won’t elevate it.
Pagelatch_up is waiting for memory not disk.
also adding files to tempdb only solves contention on the GAM, SGAM, PFS pages in tempdb only. so unless you are seeing those as contentious waits then adding tempdb files won’t solve you anything.
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You need to check if the latches are on GAM, SGAM and PFS pages. If the contention is on those pages, then adding more files might help you. If the number of files is larger then the number of CPUs, then most chances are that it won't help you. Also notice that all files should be at the same size and you should configure their growth to be the same. If the contention is on other pages, then adding new files won't help you.
Adi
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Yes, we have checked all GAM , PFS etc. stuff.
and added 4 files to tempdb.
after which the allocation contention became nearly nonexistent.
however I am looking at the sizes of all tempdb files, including the newly added, that are over 98% all the time.
should we not expect the tempdb files be MORE used?
Likes to play Chess
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This is the report of all our waits at this time, after GAM and PFS contention got resolved. This is the report that
is created based on capture of all active SPIDs via sp_whoisactive once every minute.
Any further suggestions would be greatly appreciated.
Likes to play Chess
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