On Fri, Nov 23, 2012 at 6:56 PM, Amit Kapila <amit.kap...@huawei.com> wrote: >> When I remove postgresql.auto.conf, SET PERSISTENT failed. >> >> =# SET PERSISTENT synchronous_commit = 'local'; >> ERROR: failed to open "postgresql.auto.conf" file > > There can be 2 ways to handle this, either we recreate the > "postgresql.auto.conf" file or give error. > I am not sure if user tries to delete internal files, what should be exact > behavior? > Any suggestion?
I prefer to recreate it. $PGDATA/config_dir is specified in include_dir by default. Users might create and remove the configuration files in that directory many times. So I'm not surprised even if a user accidentally removes postgresql.auto.conf in that directory. Also users might purposely remove that file to reset all the settings by SET PERSISTENT. So I think that SET PERSISTENT should handle the case where postgresql.auto.conf doesn't exist. We might be able to expect that postgresql.auto.conf is not deleted by a user if it's in $PGDATA/global or base directory. >> We should implement "RESET PERSISTENT"? Otherwise, there is no way >> to get rid of the parameter setting from postgresql.auto.conf, via SQL. >> Also >> We should implement "SET PERSISTENT name TO DEFAULT"? > > Till now, I have not implemented this in patch, thinking that it can be done > as a 2nd part if basic stuff is ready. > However I think you are right without one of "RESET PERSISTENT" or "SET > PERSISTENT name TO DEFAULT", it is difficult for user > to get rid of parameter. > Will "SET PERSISTENT name TO DEFAULT" be sufficient or do you think both are > necessary, because RESET PERSISTENT also internally might need > to behave similarly. > > For implementation of "SET PERSISTENT name TO DEFAULT", there can be 2 ways > 1) Delete the entry from postgresql.auto.conf > 2) Update the entry value in postgresql.auto.conf to default value Both seems to be useful. I think that "SET ... TO DEFAULT" is suitable for 2), and "RESET PERSISTENT ..." is suitable for 1). Another comment is: What happens if the server crashes while SET PERSISTENT is writing the setting to the file? A partial write occurs and restart of the server would fail because of corrupted postgresql.auto.conf? Regards, -- Fujii Masao -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
