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delete takes too much time.

From: Jack , Zhan Hua Ping (jackzhphotmail.com)
Date: Tue Oct 02 2007 - 08:56:29 CDT

 ====Long time ago=============

Mark wrote:

> I have my app almost complete on MaxDB. I have just run

> into a major snag

> and would appreciate any help you can offer.

>

> I have a table "Files" that has about 400,000 rows

>

> If I run queries like

> 1) SELECT * FROM FILES WHERE FILE_NAME = "THISFILE.TXT"

> OR

> 2) SELECT * FROM FILES WHERE FILE_ID = 687

>

> I get the results in a snap

>

> However If I try

>

> DELETE FROM FILES WHERE FILE_NAME = "THISFILE.TXT"

>

> This takes about 5 minutes. I thought it might be an index

> thing so I tried

>

> DELETE FROM FILES WHERE FILE_ID = 687

>

> and it still took over 5 minutes. FILE_ID is the PRIMARY KEY

> so I know it

> is already indexed. I don't think a delete should take this

> long. Please

> help.

Then Becker, Holger responded:

Did you check the possibility of lock collisions on the table.

You should have a look into system table lockstatistics.

Then Mark said:

Under the Information - Locks in the database manager I see

row Locks 312776

Table Locks 6487

These seem kind of high for what I'm doing. How do I prevent these from

occurring?

====================

However, the final result is unknown.

I have the similar problem. and the problem might not come from locks.

Since restart the database, and then i am sure no connection to it at all.

then i open SQL Studio to delete one row, it took 30 minutes to get done.

Is there anyone know what might be the problem?

How can i check the unique index on the primary key is ok?

I have check all indexes, even recreated them.

but i am not sure if the specific index on the primary key exists.

or is it relevant?

Thanks for your respond in advance!

Jack
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