RE: Timeout parameters
От | Tsunakawa, Takayuki |
---|---|
Тема | RE: Timeout parameters |
Дата | |
Msg-id | 0A3221C70F24FB45833433255569204D1FBC7561@G01JPEXMBYT05 обсуждение исходный текст |
Ответ на | Re: Timeout parameters (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>) |
Список | pgsql-hackers |
From: Kyotaro HORIGUCHI [mailto:horiguchi.kyotaro@lab.ntt.co.jp] > If so, in turn the socket_timeout doesn't work as expected? I > understand that what is proposed here is to disconnect after that > time of waiting for *the first tuple* of a query, regardless of > it is a long query or network failure. On of the problems raised > here is the socket_timetout patch doesn't work that way? No, the proposal is to set the timeout for every socket read/write like PgJDBC. It is not restricted to an SQL command execution;it applies to any communication with the server that could block the client. > I can't imagine that in the cases where other than applications > cannot be rebuild for some reasons. (E.g. the source code has > been lost or the source code no longer be built on modern > environment..) > > If an application is designed to have such a requirement, mustn't > it have implemented that by itself by any means? For example, an > application on JDBC can be designed to kill a querying thread > that takes longer than threshold. Any paid or free applications whose source code is closed. Also, ordinary users don't want to modify psql and pgAdmin sourcecode by themselves, do they? > Doesn't TCP_KEEPALIVE work that way? > > statement_timeout works on a live connection, TCP_USER_TIMEOUT > works for an already failed network but if the network fails > after a backend already sent the ack for a query request, it > doesn't work. TCP_KEEPALIVE would work for the case where any > packet doesn't reach each other for a certain time. Is there any > other situations to save? For example, OS issues such as abnormally (buggy) slow process scheduling or paging/swapping that prevent control from beingpassed to postgres. Or, abnormally long waits on lwlocks in postgres. statement_timeout doesn't take effect whilewaiting on a lwlock. I have experienced both. And, any other issues in the server that we haven't experienced andnot predictable. Regards Takayuki Tsunakawa
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