Hi, On Fri, Sep 18, 2009 at 7:34 PM, Fujii Masao <masao.fu...@gmail.com> wrote: > This approach is OK if the stand-alone walreceiver is treated steadily > by the startup process like a child process under postmaster: > > * Handling of some interrupts: SIGHUP, SIGTERM?, SIGINT, SIGQUIT... > For example, the startup process would need to rethrow walreceiver > the interrupt from postmaster. > > * Communication with other child processes: stats collector? syslogger?... > For example, the log message generated by walreceiver should also > be collected by syslogger if requested.
Also we should consider how to give a GUC parameter to the stand-alone walreceiver. In the initial patch, since walreceiver was a child process of postmaster, it could easily get any GUC parameter. But it's not so easy to give a GUC parameter to a stand-alone program. I think that at least the following parameters should affect walreceiver: * wal_sync_method I want walreceiver to use fdatasync instead of fsync for performance improvement. And other DBA might want to choose another method. * fsync I'm not surprised if someone wants to disable fsync in the standby. * some parameters for logging I think that the log messages generated by walreceiver should also be treated as well as the other postgres messages. For example, I'd like to specify log_line_prefix also for walreceiver. There are some approaches to give a GUC parameter to walreceiver. Which is the best? 1) Give a parameter as a command-line argument of the stand-alone walreceiver. This is a straightforward approach, but wouldn't cover a reload of parameter. 2) Give a parameter via pipe between the startup process and walreceiver. 3) Change walreceiver to read a configuration file. The problem is that the command-line argument of postmaster doesn't affect walreceiver. The combination of 1) and 3) might be required. 4) Change walreceiver back to a child process of postmaster. Do you have any other better approach? Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers