On Thu, Mar 21, 2024 at 9:44 AM Bharath Rupireddy <bharath.rupireddyforpostg...@gmail.com> wrote: > > Yes, usingVirtualTupleTableSlot helps improve the performance a lot. > Below are results from my testing. Note that CMV, RMV, CTAS stand for > CREATE MATERIALIZED VIEW, REFRESH MATERIALIZED VIEW, CREATE TABLE AS > respectively. These commands got faster by 62.54%, 68.87%, 74.31% or > 2.67, 3.21, 3.89 times respectively. I've used the test case specified > at [1]. > > HEAD: > CMV: > Time: 6276.468 ms (00:06.276) > CTAS: > Time: 8141.632 ms (00:08.142) > RMV: > Time: 14747.139 ms (00:14.747) > > PATCHED: > CMV: > Time: 2350.282 ms (00:02.350) > CTAS: > Time: 2091.427 ms (00:02.091) > RMV: > Time: 4590.180 ms (00:04.590) > > I quickly looked at the description of what a "virtual" tuple is from > src/include/executor/tuptable.h [2]. IIUC, it is invented for > minimizing data copying, but it also says that it's the responsibility > of the generating plan node to be sure these resources are not > released for as long as the virtual tuple needs to be valid or is > materialized. While it says this, as far as this patch is concerned, > the virtual slot gets materialized when we copy the tuples from source > slot (can be any type of slot) to destination slot (which is virtual > slot). See ExecCopySlot-> > tts_virtual_copyslot->tts_virtual_materialize. This way, > tts_virtual_copyslot ensures the tuples storage doesn't depend on > external memory because all the datums that aren't passed by value are > copied into the slot's memory context. > > With the above understanding, it looks safe to use virtual slots for > the multi insert buffered slots. I'm not so sure if I'm missing > anything here.
I'm attaching the v13 patches using virtual tuple slots for buffered tuples for multi inserts. -- Bharath Rupireddy PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
v13-0001-New-table-AMs-for-single-and-multi-inserts.patch
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v13-0002-Optimize-CREATE-TABLE-AS-with-multi-inserts.patch
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v13-0003-Optimize-REFRESH-MATERIALIZED-VIEW-with-multi-in.patch
Description: Binary data
v13-0004-Use-new-multi-insert-table-AM-for-COPY-FROM.patch
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