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9i doubts

From: <>
Date: Fri, 02 May 2003 21:56:41 -0800
Message-ID: <>

Hello list
I had some doubts I had after going thru Oracle documentation for 9i release2 :

Q1. Which components of the sga other than the shared pool and the database buffer cache are dynamically sizable ?

Q2. Which components of the sga allocate memory in granules and which do not ?

Q3. If I specify sga_max_size=199M then does upon startup, oracle allocate this much memory straight away and then start allocating it to various sga components ?

Q4. If the answer to the above question is yes then does oracle allocate 199M or an integral multiple of granule size ? ( 199M is not an exact integral multiple of 16 MB or 8MB)

Q5. "SMON is responsible for coalescing contiguous free extents within dictionay managed tablespaces"
=> then who does the coalescing within locally managed tablespaces ?

Q6. Can the oracle block size be smaller than the operating system block size ?

Q7. Is data dictionary information cached in the database buffer cache also ?

Q8. The administrators guide says "Whenever a transaction is commited a system change number is assigned to identify the redo records for each commited transaction."
=> is the scn assigned to the transaction ( which means that every statement
in the transaction gets the same scn)
or is a different scn assigned to each and every statement within the transaction " ?

Q9. "When checkpoints are not set to occur between log switches , make all groups the same size to guarantee that checkpoints occur at regular intervals" {SAG pg 7-9}
How do I disable checkpoints between log switches ? should i use fast_start_mttr_target ?

Q10. Do I have to shutdown and then go to the mount state just to rename a log member ? Can't it be done when the dataabse is open and the group is not current or active ?

Q11. Where are the free list groups and the freelists stored ?

Q12 When the server process does not find a block in the database buffer cache it fetches it from the datafile and leaves a copy in the buffer cache . What happens when Oracle has to reconstruct a read-consistent image from the undo segment ? ( example when a row has changes that were not committed at the start of the query ) . Will the existing copy of the data block in the buffer cache be over-written ?

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Received on Sat May 03 2003 - 00:56:41 CDT

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