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Add suppport for startup chunk exclusion with aggs
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In ba9b818 we added support for
chunk-wise aggregates. The pushdown of the aggregate breaks the startup
exclusion logic of the ChunkAppend node. This PR adds the support for
startup chunk exclusion with chunk-wise aggs.

Fixes: #6282
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@jnidzwetzki
jnidzwetzki committed Nov 7, 2023
1 parent 6e79687 commit 2c9304a
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Showing 3 changed files with 50 additions and 2 deletions.
14 changes: 12 additions & 2 deletions src/nodes/chunk_append/planner.c
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Expand Up @@ -401,10 +401,20 @@ ts_chunk_append_get_scan_plan(Plan *plan)
else
return NULL;
break;
case T_MergeAppend:
case T_Agg:
return NULL;
if(plan -> lefttree != NULL && IsA(plan -> lefttree, CustomScan))
{
Assert(plan -> righttree == NULL);
Assert(castNode(CustomScan, plan -> lefttree)->scan.scanrelid > 0);
return (Scan *) plan -> lefttree;
}
else
{
return NULL;
}
break;
case T_MergeAppend:
return NULL;
default:
elog(ERROR, "invalid child of chunk append: %s", ts_get_node_name((Node *) plan));
}
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34 changes: 34 additions & 0 deletions tsl/test/expected/agg_partials_pushdown.out
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,40 @@ SELECT count(*), sum(v0), sum(v1), sum(v2), sum(v3) FROM testtable WHERE time >=
Filter: ((_hyper_1_2_chunk."time" <= 'Mon Jan 31 16:00:00 2000 PST'::timestamp with time zone) AND (_hyper_1_2_chunk."time" >= ('2000-01-01 00:00:00+0'::cstring)::timestamp with time zone))
(35 rows)

-- Perform chunk append startup chunk exclusion - issue 6282
:PREFIX
SELECT count(*), sum(v0), sum(v1), sum(v2), sum(v3) FROM testtable WHERE time >= '2000-01-09 00:00:00+0'::text::timestamptz AND time <= '2000-02-01 00:00:00+0'::text::timestamptz;
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Finalize Aggregate (actual rows=1 loops=1)
Output: count(*), sum(testtable.v0), sum(testtable.v1), sum(testtable.v2), sum(testtable.v3)
-> Custom Scan (ChunkAppend) on public.testtable (actual rows=3 loops=1)
Output: (PARTIAL count(*)), (PARTIAL sum(testtable.v0)), (PARTIAL sum(testtable.v1)), (PARTIAL sum(testtable.v2)), (PARTIAL sum(testtable.v3))
Startup Exclusion: true
Runtime Exclusion: false
Chunks excluded during startup: 1
-> Partial Aggregate (actual rows=1 loops=1)
Output: PARTIAL count(*), PARTIAL sum(_hyper_1_1_chunk.v0), PARTIAL sum(_hyper_1_1_chunk.v1), PARTIAL sum(_hyper_1_1_chunk.v2), PARTIAL sum(_hyper_1_1_chunk.v3)
-> Index Scan using _hyper_1_1_chunk_testtable_time_idx on _timescaledb_internal._hyper_1_1_chunk (actual rows=0 loops=1)
Output: _hyper_1_1_chunk.v0, _hyper_1_1_chunk.v1, _hyper_1_1_chunk.v2, _hyper_1_1_chunk.v3
Index Cond: ((_hyper_1_1_chunk."time" >= ('2000-01-09 00:00:00+0'::cstring)::timestamp with time zone) AND (_hyper_1_1_chunk."time" <= ('2000-02-01 00:00:00+0'::cstring)::timestamp with time zone))
-> Partial Aggregate (actual rows=1 loops=1)
Output: PARTIAL count(*), PARTIAL sum(_hyper_1_2_chunk.v0), PARTIAL sum(_hyper_1_2_chunk.v1), PARTIAL sum(_hyper_1_2_chunk.v2), PARTIAL sum(_hyper_1_2_chunk.v3)
-> Custom Scan (DecompressChunk) on _timescaledb_internal._hyper_1_2_chunk (actual rows=10 loops=1)
Output: _hyper_1_2_chunk.v0, _hyper_1_2_chunk.v1, _hyper_1_2_chunk.v2, _hyper_1_2_chunk.v3
Vectorized Filter: ((_hyper_1_2_chunk."time" >= ('2000-01-09 00:00:00+0'::cstring)::timestamp with time zone) AND (_hyper_1_2_chunk."time" <= ('2000-02-01 00:00:00+0'::cstring)::timestamp with time zone))
Rows Removed by Filter: 15
Bulk Decompression: true
-> Seq Scan on _timescaledb_internal.compress_hyper_2_4_chunk (actual rows=5 loops=1)
Output: compress_hyper_2_4_chunk.filter_1, compress_hyper_2_4_chunk.filler_2, compress_hyper_2_4_chunk.filler_3, compress_hyper_2_4_chunk."time", compress_hyper_2_4_chunk.device_id, compress_hyper_2_4_chunk.v0, compress_hyper_2_4_chunk.v1, compress_hyper_2_4_chunk.v2, compress_hyper_2_4_chunk.v3, compress_hyper_2_4_chunk._ts_meta_count, compress_hyper_2_4_chunk._ts_meta_sequence_num, compress_hyper_2_4_chunk._ts_meta_min_1, compress_hyper_2_4_chunk._ts_meta_max_1
Filter: ((compress_hyper_2_4_chunk._ts_meta_max_1 >= ('2000-01-09 00:00:00+0'::cstring)::timestamp with time zone) AND (compress_hyper_2_4_chunk._ts_meta_min_1 <= ('2000-02-01 00:00:00+0'::cstring)::timestamp with time zone))
-> Partial Aggregate (actual rows=1 loops=1)
Output: PARTIAL count(*), PARTIAL sum(_hyper_1_2_chunk.v0), PARTIAL sum(_hyper_1_2_chunk.v1), PARTIAL sum(_hyper_1_2_chunk.v2), PARTIAL sum(_hyper_1_2_chunk.v3)
-> Index Scan using _hyper_1_2_chunk_testtable_time_idx on _timescaledb_internal._hyper_1_2_chunk (actual rows=10 loops=1)
Output: _hyper_1_2_chunk.v0, _hyper_1_2_chunk.v1, _hyper_1_2_chunk.v2, _hyper_1_2_chunk.v3
Index Cond: ((_hyper_1_2_chunk."time" >= ('2000-01-09 00:00:00+0'::cstring)::timestamp with time zone) AND (_hyper_1_2_chunk."time" <= ('2000-02-01 00:00:00+0'::cstring)::timestamp with time zone))
(27 rows)

-- Force plain / sorted aggregation
SET enable_hashagg = OFF;
SELECT count(*), sum(v0), sum(v1), sum(v2), sum(v3) FROM testtable WHERE time >= '2000-01-01 00:00:00+0'::text::timestamptz AND time <= '2000-02-01 00:00:00+0';
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4 changes: 4 additions & 0 deletions tsl/test/sql/agg_partials_pushdown.sql
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,10 @@ SELECT count(*), sum(v0), sum(v1), sum(v2), sum(v3) FROM testtable WHERE time >=
:PREFIX
SELECT count(*), sum(v0), sum(v1), sum(v2), sum(v3) FROM testtable WHERE time >= '2000-01-01 00:00:00+0'::text::timestamptz AND time <= '2000-02-01 00:00:00+0';

-- Perform chunk append startup chunk exclusion - issue 6282
:PREFIX
SELECT count(*), sum(v0), sum(v1), sum(v2), sum(v3) FROM testtable WHERE time >= '2000-01-09 00:00:00+0'::text::timestamptz AND time <= '2000-02-01 00:00:00+0'::text::timestamptz;

-- Force plain / sorted aggregation
SET enable_hashagg = OFF;

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