Suspected Postgres Datacorruption - Mailing list pgsql-performance

From Sumeet Jauhar
Subject Suspected Postgres Datacorruption
Date
Msg-id CAKN1XtpsdHSJskgqFcNQGSFSLznKmE8D=SvM8wMr82GHmk6s0Q@mail.gmail.com
Whole thread Raw
Responses Re: Suspected Postgres Datacorruption  (Scott Marlowe <scott.marlowe@gmail.com>)
Re: Suspected Postgres Datacorruption  (Greg Smith <greg@2ndquadrant.com>)
List pgsql-performance

Hi All ,


Can you please help me out with the following questions .

 

Our application is running on Postgres 7.4.X . I agree that this is a very old version of Postgres and we should have upgraded . The issue that we faced is that

 

1 . There was a system crash due to a hardware failure .

 

2 . When the system came up , we tried to insert a few records into the database . However at this point in time we saw that Postgres was taking a lot of CPU & memory .

 

Around 42% CPU consumption . This was a cause of concern .

 

3 . We re-indexed the database and it helped reduce the cpu & memory consumption .

 

My question is

 

A ) Isn’t Postgres database resilient enough to handle hardware system failure ? or it sometime results in a corrupt index for its tables ? I read on the Postgres site that hardware failure can cause corrupt indexes . Besides this are there any other scenario which may result in such corruption .

B) If there has been improvement / enhancements done by Postgres regarding the way it handles corrupt indexes can you please pass me more information  about the bug Id or some documentation on it ? Our application does not do any REINDEXING . I am in a dilemma if we should seriously incorporate it in our application .

 

I ideally want to push to a higher version of Postgres . If I can prove that there will be significant performance benefits and that crashes won’t occur then I will be able to present a strong case .


Since my question is related to Performance & Data corruption i saw on the Postgres site that i should provide the following information


Addition Info :


CPU manufacturer and model : Intel's Itanium Processor 

Do you use a RAID controller? yes


PCIe SAS SmartArray P410i RAID Controller

PCIe SAS SmartArray P411 RAID Controller


Is is Write back caching enabled ?

    Total Cache Size (MB)............... 144
    Read Cache........................ N/A

    Write Cache....................... N/A

No of disks : 4


Have you ever set fsync=off in the postgresql config file?

#fsync = true                   # turns forced synchronization on or off

I never changed it .


Have you had any unexpected power loss lately? Replaced a failed RAID disk? Had an operating system crash?  Yes system crashed had occured .


Hope this information helps .


Regards,

Sumeet


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