On 2023-08-21 Mo 08:33, Alvaro Herrera wrote:
Hello,
On 2023-Jul-12, Andrew Dunstan wrote:
+ entry = hash_search(missing_cache, &key, HASH_ENTER, &found);
+
+ if (!found)
+ {
+ /* cache miss, so we need a non-transient copy of the datum */
+ oldctx = MemoryContextSwitchTo(TopMemoryContext);
+ entry->value =
+ datumCopy(attrmiss->am_value, false, att->attlen);
+ MemoryContextSwitchTo(oldctx);
+ }
Hmm ... when exactly do these values get freed if no longer needed? Is
the theory that leaking them is not relevant?
Not sure I understand "relevant" here. They don't get freed. There will be at most one entry per row in pg_attribute where atthasmissing is true. I originally suggested cleaning them up at transaction end, but there was an argument that that might not make them sufficiently long-lived, and I don't know of any time more coarse grained when we can conveniently clean them up.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
