[pgpool-general: 132] Re: Healthcheck timeout not always respected

[Tatsuo Ishii]

> Hello pgpool community,
> 
> When system is configured for security reasons not to return destination
> host unreachable messages, even though health_check_timeout is configured,
> socket call will block and alarm will not get raised until TCP timeout
> occurs.

Interesting. So are you saying that read(2) cannot be interrupted by
alarm signal if the system is configured not to return destination
host unreachable message? Could you please guide me where I can get
such that info? (I'm not a network expert).

> Not a C programmer, found some info that select call could be replace with
> select/pselect calls. Maybe it would be best if PGCONNECT_TIMEOUT value
> could be used here for connection timeout. pgpool has libpq as dependency,
> why isn't it using libpq for the healthcheck db connect calls, then
> PGCONNECT_TIMEOUT would be applied?

I don't think libpq uses select/pselect for establishing connection,
but using libpq instead of homebrew code seems to be an idea. Let me
think about it.

One question. Are you sure that libpq can deal with the case (not to
return destination host unreachable messages) by using
PGCONNECT_TIMEOUT?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp