RE: Number of transaction table slots (was: Rollback Segment Header Dump)

Hi Gopal,

Yes, you cannot have any more concurrent transactions (including distributed queries) in a rollback segment than the number of slots available in the transaction table in the header block.

You should be able to calculate the number of slots for any database block size and for any given version from V$TYPE_SIZE without dumping a header block. For example for your 2K block size it goes like this:

      2048 bytes db_block_size

• 16 bytes cache layer undo block header (KTUBH)
• 4 bytes cache layer tail
• 72 bytes extent control header (KTECH)
• 44 bytes extent map header (KTECT)
• 968 bytes extent table = extent entry * maxextents
  • 8 bytes (KTETB) * (db_block_size/16 - 7)
• 104 bytes transaction control header (KTUXC)

  ---

  • 840 bytes for the transaction table / 40 bytes per transaction table entry (KTUXE)
  • 21 transaction table slots!

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-----Original Message-----
From: K Gopalakrishnan [mailto:kaygopal_at_yahoo.com] Sent: Tuesday, 29 August 2000 17:37
To: oracledba_at_quickdoc.co.uk
Cc: oracle-l_at_fatcity.com
Subject: Rollback Segment Header Dump

Any body know about the size of the transaction slot in the transaction table. I have dumped the header of a rollback segment (of 2 K block size ) and i am seeing only 21 slots.

Does that means only 21 ___concurrent__ transactions Received on Tue Aug 29 2000 - 04:41:00 CDT