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Help in finding large transaction

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  • Help in finding large transaction

    Hi,

    We have somewhat of a stall in our PXC setup, once or twice a day there is a query creating a huge transaction which stalls the cluster until the transaction hits the transaction limit, i.e, this is logged:
    Code:
    140504 12:34:37 [Warning] WSREP: transaction size limit (1073741824) exceeded: 1073774592
    I've tried tracking down the query causing this on my own but I can't seem to find it. Are there any way i can log querys causing large transactions?

  • #2
    Hi blodan,

    In case if query/transaction is cslow - you can check the following things:

    - entire error log
    - show engine innodb status\G
    - show global status like 'ws%'
    - you can enable slow query log and check for slow queries

    The best is to run pt-stalk (our tool):
    http://www.percona.com/doc/percona-t.../pt-stalk.html

    PTDEST=/tmp/pt/collected/`hostname`/
    mkdir -p $PTDEST;
    cd /tmp/pt;
    wget percona.com/get/pt-stalk;
    chmod +x pt*;
    sudo ./pt-stalk --no-stalk --iterations=2 --sleep=30 --dest=$PTDEST -- --user=root --pass=<mysql-root-pass>;

    Then it will collect a lot of info in $PTDEST folder and you'll be able to check info there.

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