Re: v$sess

From: Christopher Spence <cspence_at_delphi-tech.com>
Date: Wed, 08 Sep 1999 09:59:47 -0400
Message-ID: <vGrWNyUf+tykOOoqq39d8drP+oJX@4ax.com>

If Block gets are the number of blocks read to fill session requests, why is it lower than consistant? I would think it would be equal to consistant or bigger.

How do you read this view for performance? I.e. if x number is higher than x this is a problem.

Is this covered in performance tuning course? I take that one in a couple of weeks.

Oracle ID                      Block Gets       Consistent Gets

Physical Reads Block Changes Consistent Changes

------------------------------ ---------------- ----------------
---------------- ---------------- ------------------
ACEQA                                       909           79,723
8,318                9                0

For example here, Block gets are 909 meaning oracle needed to retrieve 909 blocks (from buffer and directly from disk for fts) to satisfy all the queries. 79,723 blocks where looked at while pending changes? (Thus high level of modifications being made?)

How do you put it all together? the relationship of block gets and consistant gets confuses me how block gets is lower.

On Wed, 8 Sep 1999 14:46:34 +0100, "Neilc" <neilc-olops_at_btinternet.com> wrote:

>v$sess_io lists I/O statistics for each user session.
>
>block gets are the number of database blocks read to satisfy a particular
>session.
>consistent_gets are the number of reads from rollback_segments
>physical_reads are reads of data blocks into memory from disk.
>
>Hope this helps
>
>Neil C
>
>Christopher Spence wrote in message ...
>> Could someone please explain accurately what exactly 'BLOCK
>>GETS' and 'CONSISTANT GETS' refers to under this view? I believe i
>>know wha they mean but if someone that is 100% sure can explain this
>>that would be wonderful. Also 'Physical Reads' would be great too. I
>>have heard different answers to this.
>>
>
Received on Wed Sep 08 1999 - 08:59:47 CDT

Re: v$sess_io