Re: pinning table into memory? Help!!!

I'm assuming that you've found that a statement like:

LOAD specific_table INTO MEMORY;

returns an error message in Oracle version 8.0.5 (or any other version, for that matter. You probably do realize, however, that a statement like this:

SELECT * FROM specific_table;

will access all of the used blocks in the database segment containing "specific_table", which means that each block will (at some point during the execution of the query) be loaded into memory.

However, it is not possible to specify that a table be loaded into the buffer pool in Oracle 8.0.5, other than by accessing the table through normal SQL statements.

Oracle uses an algorithm to manage the buffer pool. When a requested database block is not currently in the buffer pool, and there is no free space available in buffer pool, the least recently used blocks are flushed from the pool to make room for the newly requested blocks.

Blocks accessed through index probes or index scans are put into the "most recently used" end of the buffer pool chain, but blocks accessed via a full table scan (by default) put onto the "least recently used" end of the chain. It is possible, on a per table basis, to modify the placement of blocks accessed by a full table scan to the "most recently used" end of the buffer pool chain, by including the CACHE keyword in the create table statement. But this is not the same thing as "loading" or "pinning" a specific table "into memory".

I would advise you to use caution in specifying the CACHE keyword on any table, due to the negative impact it can have on overall database performance.

I'm making a rash assumption that the reason you would want to "pin" a table in memory is to improve performance of your database application.

There are several parameters that can be modified to tune the performance of the Oracle database, including the buffer cache.

HTH "Serge Nantel" <snantel_at_virtuo-cio.com> wrote in message news:6_j96.79294$JT5.2540096_at_news20.bellglobal.com...
> Hi all
>
> Somme one knowg how to load specifique tables into memory Oracle 8.0.5
>
> Thank all
>
>
Received on Sat Jan 20 2001 - 23:15:23 CST