On Wed, 26 Feb 2020 18:51:21 +0100 Julien Rouhaud <rjuju...@gmail.com> wrote:
> On Thu, Feb 27, 2020 at 02:35:18AM +0900, Yugo NAGATA wrote: > > Hi, > > > > Attached is a patch for allowing auto_explain to log plans before > > queries are executed. > > > > Currently, auto_explain logs plans only after query executions, > > so if a query gets stuck its plan could not be logged. If we can > > know plans of stuck queries, we may get some hints to resolve the > > stuck. This is useful when you are testing and debugging your > > application whose queries get stuck in some situations. > > Indeed that could be useful. > > > This patch adds new option log_before_query to auto_explain. > > Maybe "log_before_execution" would be better? Thanks! This seems better also to me. > > > Setting auto_explain.log_before_query option logs all plans before > > queries are executed regardless of auto_explain.log_min_duration > > unless this is set -1 to disable logging. If log_before_query is > > enabled, only duration time is logged after query execution as in > > the case of when both log_statement and log_min_duration_statement > > are enabled. > > I'm not sure about this behavior. The final explain plan is needed at least > if > log_analyze, log_buffers or log_timing are enabled. In the current patch, log_before_query (will be log_before_execution) has no effect if log_analyze is enabled in order to avoid to log the same plans twice. Instead, is it better to log the plan always twice, before and after the execution, if log_before_query is enabled regardless of log_min_duration or log_analyze? Regards, Yugo Nagata -- Yugo NAGATA <nag...@sraoss.co.jp>
