* Greg Smith (greg@xxxxxxxxxxxxxxx) wrote: > Craig Ringer wrote: >> On 1/12/2009 11:33 AM, Greg Smith wrote: >>> 1) If you spawn the psql process with bash using "&", you can then find >>> its pid with "$!", then chain through the process tree with ps and >>> pg_stat_activity as needed to figure out the backend pid. >> >> I feel like I'm missing something obvious here. How can walking the >> process tree starting with the psql pid help you find the backend pid? >> The backend and client have no relationship in the process tree. At >> some point you have to match the (ip,port) tuple for the client's >> connection against pg_stat_activity - what you've listed separately as >> (4). Even that won't help if a unix socket is in use, since >> client_addr is null and client_port is -1. > It turns out I completely misremembered what I did the last time, so > you're right to call me on this. As I confirmed when I tried to do this > myself again, the two port numbers are completely unrelated via anything > you can see in ps. What I actually did was look at pg_stat_activity, > note what processes were around, spawn the new one, and then look at > pg_stat_activity again to figure out which it is. Not really a great > approach, but a usable one for some situations. Perhaps we can stick the pid in client_addr? I havn't got a good solution at the moment for UNIX domain sockets, which really does suck. The best I've found, which is by no means a good solution, is: ===# netstat -np | grep -A1 .PGSQL | grep -B1 <pid of psql> (On a Linux system) I havn't actually been following this thread, so I'm not sure what the OP was after. For other sockets (IPv4, IPv6), IP+port can be used, of course. Thanks, Stephen
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