Caching of tables

Hi All
I want some info on caching of tables in shared pool.
1) How many tables can I or should I cache in the shared pool. You would say depends on the Shared pool size, but can you let me know what percent of shared pool.
2) Also what tables should I cache in the shared pool .
---Tables accesses frequently
---- Small tables (What size is suggested)
What other considerations I need to make while caching
I have around 20 small tables (not more than 500 rows in each) and around 5 pl/sql programs all of which will run at different times.
But all of them will not access all the 20 tables. Only 5-7 tables at a time.
Please help
Thanks
Ashwin N.

Oracle makes use of a LRU algorithm to determine what data/sql/pl/sql should remain in memory for later use. This algorithm works very well in 99% of the cases. Only if this algorithm is disturbed by e.g. big loads, it sometimes is necessary to tell Oracle what should be 'kept' and what not. Usually, this is determined as part of a performance tuning phase.
Therefore, my suggestion would be that in general you don't explicitely keep or recycle objects. Only when your requirements are such that performance becomes an issue if you do nothing you should take a look at which objects should be kept and which ones not. Typically load/stage tables should not.
O, before this confuses you (like many before you): alter table cache; does not KEEP the blocks in memory rather it puts the blocks of the table at the beginning of the LRU after a full table scan rather than at the end. alter table storage(buffer_pool keep); does keep de db blocks in memory and alter table storage (buffer_pool recycle); makes sure blocks are aged out immediately.
Hope this helps,
L.

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PL/SQL Release 11.2.0.3.0 - Production
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>
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