Hi All Please help me .
Thanks... Tamanna On Mon, Dec 5, 2011 at 12:45 PM, tamanna madaan < tamanna.mad...@globallogic.com> wrote: > Hi Tomas > > I tried it on the system having postgres-8.4.0 . And the behavior is same > . > > Cluster means a group of machines having postgres installed on all of them > . > > Same database is created on all the machines one of which working as > master DB > > on which operation (like insert/delete/update) will be performed and > others working > > as Slave Db which will get data replicated to them from master DB by slony > . In my > > cluster setup there are only two machines ( A and B ) one having master Db > and other > > being slave . I execute the below query from system A to system B : > > psql -U<db name> -h<host ip of B> -c "select sleep(300);" > > This query can be seen running on system B in `ps -eaf | grep postgres` > output . > > Now, while this query is going on, execute below command on system A which > will block any packet coming to this machine : > > iptables -I INPUT -i eth0 -j DROP . > > Afer 5 mins (which is the sleep period) , the above query will finish on > system B . But it can still be seen > > running on system A . This may be because of the reason that the message > (that the query is finished) > > have not been received by system A . > > Still I would assume that after (tcp_keepalive_time + > tcp_keepalive_probes*tcp_keepalive_intvl) , the above > > psql query should return on system A as well. But, this query doesn't > return until it is killed manually . > > What could be the reason of that ?? > > > Well , I learnt below from the release notes of postgres : > > > == > ========================================================================================= > > > > postgres 8.1 > > > server side chnages : > > > Add configuration parameters to control TCP/IP keep-alive times for idle, > interval, and count (Oliver Jowett) > > These values can be changed to allow more rapid detection of lost client > connections. > > > postgres 9.0 > > > E.8.3.9. Development Tools > > E.8.3.9.1. libpq > > > Add TCP keepalive settings in libpq (Tollef Fog Heen, Fujii Masao, Robert > Haas) > > Keepalive settings were already supported on the server end of TCP > connections. > > > > ============================================================================================== > > > Does this mean that TCP keep alive settings(that are provided in postgres > 8.1 onwards) would only work for lost connections to server and > > won't work in the case above as above case requires psql (which is client > ) to be returned ?? And for the above case the TCP keepalive settings in > libpq ( that are provided in postgres 9.0 onwards) would work ?? > > > kernel version on my system is 2.6.27.7-9-default and potstgres-8.4.0. > keepalive setting are as below : > > > postgresql.conf > > > #tcp_keepalives_idle = 0 # TCP_KEEPIDLE, in seconds; > > # 0 selects the system default > > #tcp_keepalives_interval = 0 # TCP_KEEPINTVL, in seconds; > > # 0 selects the system default > > #tcp_keepalives_count = 0 # TCP_KEEPCNT; > > # 0 selects the system default > > system level setiing : > > net.ipv4.tcp_keepalive_time = 7200 > > net.ipv4.tcp_keepalive_probes = 9 > > net.ipv4.tcp_keepalive_intvl = 75 > > Regards > > Tamanna > > > > On Thu, Dec 1, 2011 at 7:28 PM, Tomas Vondra <t...@fuzzy.cz> wrote: > >> On 1 Prosinec 2011, 12:57, tamanna madaan wrote: >> > Hi Craig >> > I am able to reproduce the issue now . I have postgres-8.1.2 installed >> in >> > cluster setup. >> >> Well, the first thing you should do is to upgrade, at least to the last >> 8.1 minor version, which is 8.1.22. It may very well be an already fixed >> bug (haven't checked). BTW the 8.1 branch is not supported for a long >> time, so upgrade to a more recent version if possible. >> >> Second - what OS are you using, what version? The keep-alive needs support >> at OS level, and if the OS is upgraded as frequently as the database (i.e. >> not at all), this might be already fixed. >> >> And finally - what do you mean by 'cluster setup'? >> >> Tomas >> >> > > > -- > Tamanna Madaan | Associate Consultant | GlobalLogic Inc. > Leaders in Software R&D Services > ARGENTINA | CHILE | CHINA | GERMANY | INDIA | ISRAEL | UKRAINE | UK | USA > > Office: +0-120-406-2000 x 2971 > > www.globallogic.com > > > -- Tamanna Madaan | Associate Consultant | GlobalLogic Inc. Leaders in Software R&D Services ARGENTINA | CHILE | CHINA | GERMANY | INDIA | ISRAEL | UKRAINE | UK | USA Office: +0-120-406-2000 x 2971 www.globallogic.com
