IDS Forum

RE: error -245

Posted By:
Date:

Ravi

How are you loading the data? If you are doing it in one hit (and no
explicit commits after every x records) then all inserted records (and index
entries) will be locked until the load session completes (use onstat -u to
observe locks increasing at a phenomenal rate !! :-) ). Use dbload (or one
of Art's scripts) to load and commit every, say 10%, of the load file.

An isolation level of dirty read will actually skip any locked records so
you may not see all the records returned that are present.

Keith

-> -----Original Message-----
-> From: rkusenet [mailto:rkusenet@sympatico.ca]
-> Sent: Saturday, April 26, 2003 12:16 AM
-> To: ids@iiug.org
-> Subject: error -245 [1004]
->
->
-> Hi,
->
-> We have a legacy application which does not use logging. We
-> are trying to
-> convert it to a logged database with minimum application
-> change. First
-> we converted the database to a logged (unbuffered) and
-> sporadically we
-> get error -245. Next we added set lock mode to wait 15 in our code,
-> but we still get.
->
-> I have a tool which queries sysmaster database to find out
-> about locks.
-> So what I did was to run that tool and it printed out the locking
-> contention.
-> Looking at the table/index which shows lock error 245, I
-> reconstructed
-> the application scenario in a test case:-
->
-> 1. From a session I continuously load large number of rows
-> into a table.
->
-> 2. From many sessions I query the table where the data is
-> getting loaded.
-> Sure enuf, some of the sessions crap out with this error.
->
-> Both (1) and (2) are with set lock mode to wait 15. However both (1)
-> and (2) are not within begin work and commit work. That is bcos our
-> application does not use begin work, commit work.
->
-> Changing the lock mode to wait 30 also spews out error in (2).
-> finally what I did was to issue set isolation level to dirty read.
-> All errors vanished.
->
-> From what I understand, while inserting, informix does a
-> lock on index key.
-> And if at that time another session tries to read that key
-> (our application
-> queries on the key only), it spews out error 245 or 243. Why
-> does lock mode
-> 15
-> fail. Sure, a record does not take 30 seconds to insert, or even 15.
->
-> Second question: What happens when I issue dirty read. How
-> does it behave
-> in a logged database.
->
-> Am I missing something. I thought we should not have problem
-> like above.
->
-> TIA.
->
-> ravi
->
->
->

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Messages In This Thread

• error -245
  rkusenet -- Friday, 25 April 2003, at 7:16 p.m.
  • RE: error -245
    Simmons, Keith -- Monday, 28 April 2003, at 4:15 a.m.

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