On 1/25/21 9:14 AM, bu...@sohu.com wrote:
Now, I rewrite batch hashagg and sort, add some comment and combin too
patches. base on master 2ad78a87f018260d4474eee63187e1cc73c9b976.
They are support rescan and change GUC
enable_batch_hashagg/enable_batch_sort to
max_hashagg_batches/max_sort_batch, default value is "0"(mean is disable).
The "max_hashagg_batches" in grouping sets each chain using this value,
maybe we need a better algorithm.
Do not set "max_sort_batch" too large, because each tuplesort's work
memory is "work_mem/max_sort_batch".
Next step I want use batch sort add parallel merge join(thinks Dilip
Kumar) and except/intersect support after this patch commit, welcome to
discuss.
This patch has not gotten any review in the last two CFs and is unlikely
to be committed for PG14 so I have moved it to the 2021-07 CF. A rebase
is also required so marked Waiting for Author.
I can see this is a work in progress, but you may want to consider the
several suggestions that an unbuffered approach might be better.
Regards,
--
-David
da...@pgmasters.net
