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Checking Whether a Transaction Log Is TooSmall  



If transaction performance has deteriorated on a node, checkwhether its transaction log is too small.

Monitoring Transaction Performance describeshow to find out whether transaction performance has deteriorated.

How to Perform This Task

  1. Log in to thenode that the transaction log belongs to.

  2. Check how many times the transaction log has stalled,using LMCP's SHOW LOG/CURRENT command:
    $ RUN SYS$SYSTEM:LMCPLMCP> SHOW LOG/CURRENT
    Note the number of checkpoints and stalls displayed by thiscommand.

  3. Wait for five minutes, then repeat the SHOW LOG/CURRENTcommand. Note the number of checkpoints and stalls again.

  4. Compare the information from the SHOW LOG/CURRENTcommands:

    If the number of checkpoints has not changed, wait until thesystem is busier, then try this task again.

    If the number of checkpoints has increased, and the numberof stalls has increased by more than one, the transaction log istoo small.

  5. If the transaction log is too small, increase itssize. For information about how to change the size of a transactionlog, see Changing the Size of a Transaction Log.

Example

This example shows how to check whether node BLUE's transactionlog is too small.

Log in to node BLUE. Then check how many times the transactionlog has stalled: 

$ RUN SYS$SYSTEM:LMCPLMCP> SHOW LOG/CURRENTCheckpoint starts/ends            2464/2464Stall starts/ends                   21/21Log status: no checkpoint in progress, no stall in progress.
The number of checkpoints is 2464, and the transaction loghas stalled 21 times.

Wait for five minutes, then repeat the SHOW LOG/CURRENT command: 

LMCP> SHOW LOG/CURRENTCheckpoint starts/ends            2514/2514Stall starts/ends                   28/28Log status: no checkpoint in progress, no stall in progress.
The number of checkpoints has increased since the previousreading, and the transaction log has now stalled 28 times, an increaseof 7. This means that the transaction log is too small.
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