On Sat, Mar 09, 2024 at 09:09:39PM +0530, Kambam Vinay wrote: > We observed a slight lag in timestamp for a few logs from the emit_log_hook > hook implementation when the log_line_prefix GUC has '%m'. > > Upon debugging, we found that the saved_timeval_set variable is set to > 'true' in get_formatted_log_time() but is not reset to 'false' until the > next call to send_message_to_server_log(). Due to this, saved_timeval_set > will be true during the execution of hook emit_log_hook() which prefixes > the saved timestamp 'saved_timeval' from the previous log line (our hook > implementation calls log_line_prefix()). > > Attached patch sets the saved_timeval_set to false before executing the > emit_log_hook()
Indeed. If you rely on log_line_prefix() in your hook before the server side elog, the saved timestamp would not match with what could be computed in the follow-up send_message_to_server_log or send_message_to_frontend. Hmm. Shouldn't we remove the forced reset of formatted_log_time for the 'm' case in log_status_format() and remove the reset done at the beginning of send_message_to_server_log()? One problem with your patch is that we would still finish with a different saved_timeval in the hook and in send_message_to_server_log(), but we should do things so as the timestamps are the same for the whole duration of EmitErrorReport(), no? It seems to me that a more correct solution would be to reset saved_timeval_set and formatted_log_time[0] once before the hook, at the beginning of EmitErrorReport(). -- Michael
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