There are also all the context
Is the hadware OK ? (lost of a memory slot, HDD in rebuild phase, HDD crash in a RAID, lost of a processor,...)
Is the OS OK ? Is there any changement to the OS, or new programs or configurations,....
Is the database OK ? temporary space, memory, process, tablespaces, ....
Xavier
----- Original Message -----
From: "JAIMURUGAN Shanmuga Velayutham " <oracledba-ezmlmshield-x23705609.[Email address protected]
To: "LazyDBA Discussion" <[Email address protected]
Subject: Select Count(*) very fast yesterday but its slow today
Date: Tue, 31 May 2005 15:47:53 +0530
>
> Hi all,
> This was the question recently I encountered in an interview. I gave the
> answers below but that doesn't seem to satisfy the interviewer.
>
> QUESTION:-
> SELECT COUNT (*) FROM TABLE_NAME:
> The query ran fine and I got the output in less than 25 seconds.
> The next day I ran the same query and I got the output after 15 minutes.
> What is the reason for this? As a DBA what is that you will check
> immediately?
>
> My Answer:-
> 1. Mass insert or mass delete would have happened in the table,
> Statistics were not gathered after that .So the performance has
> degraded.
> 2. Statistics would have been deleted.
>
> Are there any other reasons for the performance degradation?
>
> Thanks in advance
>
> JAIMURUGAN
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DEGAND XAVIER
DX SPRL
BRUSSELS, BELGIUM
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