On Wed, May 11, 2016 at 1:34 PM, Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote:
> On 2016/05/11 16:49, Ashutosh Bapat wrote: > >> The patch is calculating user mapping when it's readily available >> through RelOptInfo::fdw_private. That incurs a catalog lookup >> unnecessarily. Instead, can we add new function makeOid, oidVal on the >> lines of makeInteger and intVal to store and retrieve an OID resp. and >> also corresponding print function? It might be helpful in future. >> > > That might be an idea, but is the overhead in that re-calculation so large? > > A call to GetForeignTable would incur a catalog lookup which means a catalog table/index scan if corresponding entry is not in the cache. This is followed by GetUserMapping() which is another catalog access. That's bound to be expensive than an makeOid(), oidVal() call. -- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company
