Re: [HACKERS] lock mode for ControlFileLock which pg_start_backup uses

2010-03-09 Thread Takahiro Itagaki
Fujii Masao wrote: > Currently pg_start_backup() accesses the shared ControlFile > by using ControlFileLock with LW_EXCLUSIVE lock mode. But > since that access is read-only operation, LW_SHARED should > be chosen instead of LW_EXCLUSIVE. > > The attached patch changes the lock mode which pg_st

Re: [HACKERS] lock mode for ControlFileLock which pg_start_backup uses

2010-03-09 Thread Heikki Linnakangas
Takahiro Itagaki wrote: > Fujii Masao wrote: >> The attached patch changes the lock mode which pg_start_backup() >> uses. Is it worth applying this patch? > > I think the patch is reasonable to represent what we are doing, > even if there is no performance benefits from it. Agreed. -- Heikki

Re: [HACKERS] lock mode for ControlFileLock which pg_start_backup uses

2010-03-08 Thread Takahiro Itagaki
Fujii Masao wrote: > Currently pg_start_backup() accesses the shared ControlFile > by using ControlFileLock with LW_EXCLUSIVE lock mode. But > since that access is read-only operation, LW_SHARED should > be chosen instead of LW_EXCLUSIVE. Almost all operations of ControlFileLock is in LW_EXCLUS

[HACKERS] lock mode for ControlFileLock which pg_start_backup uses

2010-03-08 Thread Fujii Masao
Hi, Currently pg_start_backup() accesses the shared ControlFile by using ControlFileLock with LW_EXCLUSIVE lock mode. But since that access is read-only operation, LW_SHARED should be chosen instead of LW_EXCLUSIVE. The attached patch changes the lock mode which pg_start_backup() uses. Is it wort