Re: deleting many rows from a table

From: vsevolod afanassiev <vsevolod.afanassiev_at_gmail.com>
Date: Thu, 14 Jan 2010 12:54:31 -0800 (PST)
Message-ID: <7d3b37de-876c-4896-8a63-1fac14acd9bf_at_c34g2000yqn.googlegroups.com>

Deleting data: I guess if you want to avoid outage then the only way is to run DELETE statement.
Re-organizing the table: it depends on what you are trying to achieve. You mention improving performance, do you have queries that select columns other than VALUE (LOB column)? Or all queries against this table select VALUE column? Are LOBs stored inline or nor (view DBA_LOBS column IN_ROW)? What is average LOB size compared with block size? In some cases it is preferable to store LOB in the same block as other columns, in other cases out-of-line storage is better. If you don't plan to change LOB storage then it may be sufficient to delete data, rebuild indexes, and leave table as it is.

Received on Thu Jan 14 2010 - 14:54:31 CST

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