Hello Hackers, While working on some issue in logical decoding, I found some inconsistencies in the comment for defining max_cached_tuplebufs in reorderbuffer.c. It only exists till PG10 because after that the definition got removed by the generational memory allocator patch. The variable is defined as follows in reorderbuffer.c: static const Size max_cached_tuplebufs = 4096 * 2; /* ~8MB */
And it gets compared with rb->nr_cached_tuplebufs in
ReorderBufferReturnTupleBuf as follows:
if (tuple->alloc_tuple_size == MaxHeapTupleSize &&
rb->nr_cached_tuplebufs < max_cached_tuplebufs)
{
rb->nr_cached_tuplebufs++;
}
So, what this variable actually tracks is 4096 * 2 times
MaxHeapTupleSize amount of memory which is approximately 64MB. I've
attached a patch to modify the comment.
But, I'm not sure whether the intention was to keep 8MB cache only. In
that case, I can come up with another patch.
Thoughts?
--
Thanks & Regards,
Kuntal Ghosh
EnterpriseDB: http://www.enterprisedb.com
0001-Fix-comment-for-max_cached_tuplebufs-definition.patch
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