Tom Lane wrote:
Emmanuel Cecchet <m...@asterdata.com> writes:
Tom Lane wrote:
This looks like the patch is trying to create a data structure in a
memory context that's not sufficiently long-lived for the use of the
structure. If you do this in a non-cassert build, it will seem to
work, some of the time, if the memory in question happens to not
get reallocated to something else.
I was using the CacheMemoryContext. Could someone tell me why this is
wrong and what should have been the appropriate context to use?
Well, (a) I doubt you really were creating the list in
CacheMemoryContext, else it'd have not gotten clobbered; (b) creating
statement-local data structures in CacheMemoryContext is entirely
unacceptable anyway, because then they represent a permanent memory
leak.
Well I thought that this code would do it:
child_table_lru = (OidLinkedList
*)MemoryContextAlloc(
+ CacheMemoryContext,
sizeof(OidLinkedList));
...
+ /* Add the new entry in head of the list */
+ new_head = (OidCell *) MemoryContextAlloc(
+ CacheMemoryContext, sizeof(OidCell));
The right context for statement-lifetime data structures is generally
the CurrentMemoryContext the statement code is called with.
Actually the list is supposed to stay around between statement
executions. You don't want to restart with a cold cache at every
statement so I really want this structure to stay in memory at a more
global level.
Emmanuel
--
Emmanuel Cecchet
Aster Data
Web: http://www.asterdata.com
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