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Disable gapfill on distributed hypertable

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There are number of issues when time_bucket_gapfill is run on
distributed hypertable. Thus a non-supported error is returned in this
case until the issues are fixed.
This commit is contained in:
Ruslan Fomkin 2020-09-03 10:44:58 +02:00 committed by Ruslan Fomkin
parent d5a6a5b193
commit 1fa072acb4
6 changed files with 101 additions and 6 deletions
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5
tsl/src/fdw/data_node_scan_plan.c
View File

@ -486,6 +486,11 @@ data_node_scan_add_node_paths(PlannerInfo *root, RelOptInfo *hyper_rel)
ts_cache_release(hcache);
}
/*
* Creates CustomScanPath for the data node and adds to output_rel. No custom_path is added,
* i.e., it is encapsulated by the CustomScanPath, so it doesn't inflate continuation of the
* planning and will be planned locally on the data node.
*/
void
data_node_scan_create_upper_paths(PlannerInfo *root, UpperRelationKind stage, RelOptInfo *input_rel,
RelOptInfo *output_rel, void *extra)

22
tsl/src/nodes/gapfill/planner.c
View File

@ -396,10 +396,12 @@ gapfill_path_create(PlannerInfo *root, Path *subpath, FuncExpr *func)
}
/*
* Prepend GapFill node to every group_rel path
* Prepend GapFill node to every group_rel path.
* The implementation assumes that TimescaleDB planning hook is called only once
* per grouping.
*/
void
plan_add_gapfill(PlannerInfo *root, RelOptInfo *group_rel)
plan_add_gapfill(PlannerInfo *root, RelOptInfo *group_rel, bool dist_ht)
{
ListCell *lc;
Query *parse = root->parse;
@ -409,7 +411,10 @@ plan_add_gapfill(PlannerInfo *root, RelOptInfo *group_rel)
return;
/*
* look for time_bucket_gapfill function call
* Look for time_bucket_gapfill function call in the target list, which
* will succeed on every call to plan_add_gapfill, thus it will lead to
* incorrect query plan if plan_add_gapfill is called more than once per
* grouping.
*/
gapfill_function_walker((Node *) parse->targetList, &context);
@ -421,6 +426,17 @@ plan_add_gapfill(PlannerInfo *root, RelOptInfo *group_rel)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("multiple time_bucket_gapfill calls not allowed")));
/* Executing time_bucket_gapfill on distributed hypertable produces incorrect result,
* returns internal planning error or crashes if grouping includes a space dimension.
* Thus time_bucket_gapfill is temporary disabled until it is fixed.
*/
if (dist_ht)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("time_bucket_gapfill not implemented for distributed hypertable"),
errdetail("Current version doesn't implement support for time_bucket_gapfill on "
"distributed hypertables.")));
if (context.count == 1)
{
List *copy = group_rel->pathlist;

2
tsl/src/nodes/gapfill/planner.h
View File

@ -8,7 +8,7 @@
#include <postgres.h>
void plan_add_gapfill(PlannerInfo *, RelOptInfo *);
void plan_add_gapfill(PlannerInfo *root, RelOptInfo *group_rel, bool dist_ht);
void gapfill_adjust_window_targetlist(PlannerInfo *root, RelOptInfo *input_rel,
RelOptInfo *output_rel);

6
tsl/src/planner.c
View File

@ -49,11 +49,13 @@ tsl_create_upper_paths_hook(PlannerInfo *root, UpperRelationKind stage, RelOptIn
RelOptInfo *output_rel, TsRelType input_reltype, Hypertable *ht,
void *extra)
{
bool dist_ht = false;
switch (input_reltype)
{
case TS_REL_HYPERTABLE:
case TS_REL_HYPERTABLE_CHILD:
if (hypertable_is_distributed(ht))
dist_ht = hypertable_is_distributed(ht);
if (dist_ht)
data_node_scan_create_upper_paths(root, stage, input_rel, output_rel, extra);
break;
default:
@ -61,7 +63,7 @@ tsl_create_upper_paths_hook(PlannerInfo *root, UpperRelationKind stage, RelOptIn
}
if (UPPERREL_GROUP_AGG == stage)
plan_add_gapfill(root, output_rel);
plan_add_gapfill(root, output_rel, dist_ht);
else if (UPPERREL_WINDOW == stage && IsA(linitial(input_rel->pathlist), CustomPath))
gapfill_adjust_window_targetlist(root, input_rel, output_rel);
else if (ts_guc_enable_async_append && UPPERREL_FINAL == stage &&

38
tsl/test/expected/dist_api_calls.out
View File

@ -216,6 +216,44 @@ _timescaledb_internal._dist_hyper_1_8_chunk
(1 row)
-- Simple test of time_bucket_gapfill, which is disabled for now.
\set ON_ERROR_STOP 0
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-02 18:00'),
first(value, time),
avg(value)
FROM disttable
GROUP BY 1;
ERROR: time_bucket_gapfill not implemented for distributed hypertable
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-01 18:00'),
device,
first(value, time),
avg(value)
FROM disttable
GROUP BY 1,2;
ERROR: time_bucket_gapfill not implemented for distributed hypertable
SELECT
time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-01 18:00'),
lag(min(time)) OVER ()
FROM disttable
GROUP BY 1;
ERROR: time_bucket_gapfill not implemented for distributed hypertable
-- Test the same queries with enabled partitionwise aggregate
SET enable_partitionwise_aggregate = 'on';
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-02 18:00'),
first(value, time),
avg(value)
FROM disttable
GROUP BY 1;
ERROR: time_bucket_gapfill not implemented for distributed hypertable
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-01 18:00'),
device,
first(value, time),
avg(value)
FROM disttable
GROUP BY 1,2;
ERROR: time_bucket_gapfill not implemented for distributed hypertable
SET enable_partitionwise_aggregate = 'off';
\set ON_ERROR_STOP 1
-- Ensure that move_chunk() and reorder_chunk() functions cannot be used
-- with distributed hypertable
SET ROLE TO DEFAULT;

34
tsl/test/sql/dist_api_calls.sql
View File

@ -67,6 +67,40 @@ SELECT * FROM disttable ORDER BY time;
SELECT * FROM show_chunks('disttable');
SELECT * FROM test.remote_exec(NULL, $$ SELECT show_chunks('disttable'); $$);
-- Simple test of time_bucket_gapfill, which is disabled for now.
\set ON_ERROR_STOP 0
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-02 18:00'),
first(value, time),
avg(value)
FROM disttable
GROUP BY 1;
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-01 18:00'),
device,
first(value, time),
avg(value)
FROM disttable
GROUP BY 1,2;
SELECT
time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-01 18:00'),
lag(min(time)) OVER ()
FROM disttable
GROUP BY 1;
-- Test the same queries with enabled partitionwise aggregate
SET enable_partitionwise_aggregate = 'on';
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-02 18:00'),
first(value, time),
avg(value)
FROM disttable
GROUP BY 1;
SELECT time_bucket_gapfill('3 hours', time, '2017-01-01 06:00', '2017-01-01 18:00'),
device,
first(value, time),
avg(value)
FROM disttable
GROUP BY 1,2;
SET enable_partitionwise_aggregate = 'off';
\set ON_ERROR_STOP 1
-- Ensure that move_chunk() and reorder_chunk() functions cannot be used
-- with distributed hypertable
SET ROLE TO DEFAULT;