• Fujii Masao's avatar
    pgbench: Stop counting skipped transactions as soon as timer is exceeded. · b27d0cd3
    Fujii Masao authored
    When throttling is used, transactions that lag behind schedule by
    more than the latency limit are counted and reported as skipped.
    Previously, there was the case where pgbench counted all skipped
    transactions even if the timer specified in -T option was exceeded.
    This could take a very long time to do that especially when unrealistically
    high rate setting in -R option caused quite a lot of transactions that
    lagged behind schedule. This could prevent pgbench from ending
    immediately, and so pgbench could look like it got stuck to users.
    
    To fix the issue, this commit changes pgbench so that it stops counting
    skipped transactions as soon as the timer is exceeded. The timer can
    make pgbench end soon even when there are lots of skipped transactions
    that have not been counted yet.
    
    Note that there is no guarantee that all skipped transactions are
    counted under -T though there is under -t. This is OK in practice
    because it's very unlikely to happen with realistic setting. Also this is
    not the issue that this commit newly introdues. There used to be
    the case where pgbench ended without counting all skipped
    transactions since before.
    
    Back-patch to v14. Per discussion, we decided not to bother
    back-patch to the stable branches because it's hard to imagine
    the issue happens in practice (with realistic setting).
    
    Author: Yugo Nagata, Fabien COELHO
    Reviewed-by: Greg Sabino Mullane, Fujii Masao
    Discussion: https://postgr.es/m/20210613040151.265ff59d832f835bbcf8b3ba@sraoss.co.jp
    b27d0cd3
pgbench.c 181 KB