Robert Haas <robertmh...@gmail.com> writes: > On Wed, Jan 19, 2011 at 12:10 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Robert Haas <robertmh...@gmail.com> writes: >>> Yeah. Many-times-repeated detoasting is really bad, and this is not >>> the only place in the backend where we have this problem. :-(
>> Yeah, there's been some discussion of a more general solution, and I >> think I even had a trial patch at one point (which turned out not to >> work terribly well, but maybe somebody will have a better idea someday). > I'm pretty doubtful that there's going to be a general solution to > this problem - I think it's going to require gradual refactoring of > problem spots. Do you remember the previous discussion? One idea that was on the table was to make the TOAST code maintain a cache of detoasted values, which could be indexed by the toast pointer OIDs (toast rel OID + value OID), and then PG_DETOAST_DATUM might give back a pointer into the cache instead of a fresh value. In principle that could be done in a fairly centralized way. The hard part is to know when a cache entry is not actively referenced anymore ... regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers