Обсуждение: session id and global storage
Hi, I cant find any function, which tells me something like session id. Is there something like that? I need it in my AM, because I need to know, if something which I wrote in file was written in this current session or previously. And second thing - it would be great if I could save pointer in some global storage, because I would like to access my dynamically created tree in more subsequent scans, which is impossible with void pointer stored just in opaque scan structure:( Thnaks, David Hoksza
Something like this would be maybe possible, but this select can return more rows, when the user is connected with more instances... David Hoksza ________________________________ >> Hi, I cant find any function, which tells me something like session >> id. Is there something like that? I need it in my AM, because I need >> to know, if something which I wrote in file was written in this >> current session or previously. AL> How about AL> select procpid||' '||backend_start from pg_stat_activity; AL> Yours, AL> Laurenz Albe
It seems MyProcID is what I was searching for... David Hoksza ________________________________ DH> Something like this would be maybe possible, but this select can DH> return more rows, when the user is connected with more instances... DH> David Hoksza DH> ________________________________ >>> Hi, I cant find any function, which tells me something like session >>> id. Is there something like that? I need it in my AM, because I need >>> to know, if something which I wrote in file was written in this >>> current session or previously. AL>> How about AL>> select procpid||' '||backend_start from pg_stat_activity; AL>> Yours, AL>> Laurenz Albe DH> ---------------------------(end of DH> broadcast)--------------------------- DH> TIP 5: don't forget to increase your free space map settings
Ühel kenal päeval, N, 2006-06-01 kell 10:10, kirjutas David Hoksza: > It seems MyProcID is what I was searching for... > On a buzy server with lots of connects, procID will repeat quite often. -- ---------------- Hannu Krosing Database Architect Skype Technologies OÜ Akadeemia tee 21 F, Tallinn, 12618, Estonia Skype me: callto:hkrosing Get Skype for free: http://www.skype.com
Hannu Krosing said: > Ãhel kenal päeval, N, 2006-06-01 kell 10:10, kirjutas David Hoksza: >> It seems MyProcID is what I was searching for... >> > > On a buzy server with lots of connects, procID will repeat quite often. > log_line-prefix has a sessionid gadget: Session ID: A unique identifier for each session. It is 2 4-byte hexadecimal numbers (without leading zeros) separated by a dot. The numbers are the session start time and the process ID Assuming PIDs are not reused within one second that will be unique. cheers andrew
>>> Hi, I cant find any function, which tells me something like session >>> id. Is there something like that? I need it in my AM, because I need >>> to know, if something which I wrote in file was written in this >>> current session or previously. >> >> How about >> select procpid||' '||backend_start from pg_stat_activity; >> Yours, >> Laurenz Albe > >Something like this would be maybe possible, but this select can >return more rows, when the user is connected with more instances... > >David Hoksza You could do this: SELECT procpid||' '||backend_startFROM pg_stat_activityWHERE datname = current_database()AND usename = session_userAND client_addr= inet_client_addr()AND client_port = inet_client_port(); Regards, Rodrigo
Rodrigo De Leon wrote: >>>> Hi, I cant find any function, which tells me something like session >>>> id. Is there something like that? I need it in my AM, because I need >>>> to know, if something which I wrote in file was written in this >>>> current session or previously. >>> >>> >>> How about >>> select procpid||' '||backend_start from pg_stat_activity; >>> Yours, >>> Laurenz Albe >> >> >> Something like this would be maybe possible, but this select can >> return more rows, when the user is connected with more instances... >> > > You could do this: > > SELECT procpid||' '||backend_start > FROM pg_stat_activity > WHERE datname = current_database() > AND usename = session_user > AND client_addr = inet_client_addr() > AND client_port = inet_client_port(); > That's pretty roundabout. We already expose (hex coded) pid.starttime as a session identifier in log_line_prefix (it's the %c escape) so I don't see any reason not to provide either the same thing directly in a function, or at least to expose the backend pid. If you need it in backend C code, the data can be fetched from MyProcPid and MyProcPort->session_start.tv_sec cheers andrew
> That's pretty roundabout. We already expose (hex coded) pid.starttime as > a session identifier in log_line_prefix (it's the %c escape) so I don't > see any reason not to provide either the same thing directly in a > function, or at least to expose the backend pid. That would be nice.
Andrew Dunstan <andrew@dunslane.net> writes:
> Rodrigo De Leon wrote:
>> You could do this:
>>
>> SELECT procpid||' '||backend_start
>> FROM pg_stat_activity
>> WHERE datname = current_database()
>> AND usename = session_user
>> AND client_addr = inet_client_addr()
>> AND client_port = inet_client_port();
> That's pretty roundabout.
Indeed. Use pg_backend_pid() instead:
SELECT whatever FROM pg_stat_activity WHERE procpid = pg_backend_pid();
A difficulty with this in existing releases is that pg_stat_activity
lags behind reality, so that you won't see your session listed in it
until you've been connected at least half a second or so. 8.2 won't
have that problem.
regards, tom lane