On Tue, 2008-09-02 at 18:30 +0900, ITAGAKI Takahiro wrote: > Simon Riggs <[EMAIL PROTECTED]> wrote: > > > > Why do we need to set rmgr_hook in _PG_init(), and add or mofify rmgrs > > > in our hook functions? > > > > If we modify RmgrTable in _PG_init() then we would have to have that > > structure available in all backends, which was a stated objective to > > avoid. We would still need a fast access data structure for the > > XLogInsert() check, so the RmgrTable would just be wasted space in all > > normal backends. In the patch, plugin is only called when we call > > RmgrInitialize(), so the memory is malloc'd only when required. > > Um? AFAICS RmgrTable is not accessed in XLogInsert unless we use WAL_DEBUG.
Exactly why I want to malloc it. > I see that RmgrTable should be malloc'd when required, > but there is another issue; when to load rmgr libraries. > Rmgr objects are needed only in startup process during recovery. > If we want to reduce resource consumption by rmgrs, I think it is > better not to load rmgr libraries through shared_preload_libraries. > We don't have to load rmgr libs if recovery is not needed or after recovery. > > How about adding a new variable "recovery_preload_libaries" like as > shared_preload_libraries? Rmgr libs in it are loaded only in startup > process and only if recovery is needed. Good point. If others agree, I will re-implement this way. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
