On 05/28/2014 02:04 AM, Dmitry Samonenko wrote:
On Tue, May 27, 2014 at 6:10 PM, Tom Lane <tgl@xxxxxxxxxxxxx
<mailto:tgl@xxxxxxxxxxxxx>> wrote:
Would you provide some evidence for these claims? If the keepalive
stuff
didn't work, somebody would certainly have noticed by now.
Sure. I'll try to provide it.
Our general approach to network-error handling is that dropping a
connection is a last resort, and thus it's usually inappropriate to
try to
force the network stack to fail more quickly than it was designed to do.
While you can override the keepalive timing if you insist, we won't
consider a patch that would make PG use something other than the network
stack's default settings by default, if you get my drift.
regards, tom lane
Yes, I understand this. Don't get me wrong - I'm not trying to force
some hard limitations on network stack. Actually, I'm trying to find a
way for a libpq user to get more control on query execution. I believe
that the user knows best how much time query needs to execute. After
all, she has authored it. Currently, I do not see an interface to limit
query execution time (on libpq part).
Something like: "This query execution should take no more that 15
seconds. Alarm me with error if this timer gets exceeded". And by "query
execution" I mean: "transmitting request, server execution, receiving
result back". I think such feature would be nice.
Otherwise, with current libpq state (with infinite poll timeout) if you
are using sync requests - you may experience uncontrolled long pauses.
Not sure I entirely follow what you want, but would not setting
statement_timeout work:
http://www.postgresql.org/docs/9.3/interactive/runtime-config-client.html#RUNTIME-CONFIG-CLIENT-STATEMENT
statement_timeout (integer)
Abort any statement that takes more than the specified number of
milliseconds, starting from the time the command arrives at the server
from the client. If log_min_error_statement is set to ERROR or lower,
the statement that timed out will also be logged. A value of zero (the
default) turns this off.
Setting statement_timeout in postgresql.conf is not recommended
because it would affect all sessions.
Thank you.
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
