Re: [PoC] Improve dead tuple storage for lazy vacuum

On Sun, Aug 27, 2023 at 7:53 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
wrote:
>
> I've updated the regression tests for tidstore so that it uses SQL
> functions to add blocks/offsets and dump its contents. The new test
> covers the same test coverages but it's executed using SQL functions
> instead of executing all tests in one SQL function.

This is much nicer and more flexible, thanks! A few questions/comments:

tidstore_dump_tids() returns a string -- is it difficult to turn this into
a SRF, or is it just a bit more work?

The lookup test seems fine for now. The output would look nicer with an
"order by tid".

I think we could have the SQL function tidstore_create() take a boolean for
shared memory. That would allow ad-hoc testing without a recompile, if I'm
not mistaken.

+SELECT tidstore_set_block_offsets(blk, array_agg(offsets.off)::int2[])
+ FROM blocks, offsets
+ GROUP BY blk;
+ tidstore_set_block_offsets
+----------------------------
+
+
+
+
+
+(5 rows)

Calling a void function multiple times leads to vertical whitespace, which
looks a bit strange and may look better with some output, even if
irrelevant:

-SELECT tidstore_set_block_offsets(blk, array_agg(offsets.off)::int2[])
+SELECT row_number() over(order by blk), tidstore_set_block_offsets(blk,
array_agg(offsets.off)::int2[])

row_number | tidstore_set_block_offsets
------------+----------------------------
1 |
2 |
3 |
4 |
5 |
(5 rows)

--
John Naylor
EDB: http://www.enterprisedb.com