postgres/timescaledb
1
0
Fork 0
mirror of https://github.com/timescale/timescaledb.git synced 2025-05-17 19:13:16 +08:00
Code Issues Packages Projects Releases Wiki Activity

Do not use row-by-row fetcher for parameterized plans

Browse Source 
We have to prepare the data node statement in this case, and COPY
queries don't work with prepared statements.
This commit is contained in:
Alexander Kuzmenkov 2022-09-15 20:13:15 +03:00 committed by Alexander Kuzmenkov
parent 424f6f7648
commit fee27484ce
5 changed files with 114 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/planner/planner.c
View File

@ -615,6 +615,7 @@ timescaledb_planner(Query *parse, int cursor_opts, ParamListInfo bound_params)
PG_CATCH();
{
ts_baserel_info = NULL;
ts_data_node_fetcher_scan_type = AutoFetcherType;
/* Pop the cache, but do not release since caches are auto-released on
* error */
planner_hcache_pop(false);

21
tsl/src/fdw/scan_exec.c
View File

@ -152,6 +152,27 @@ create_data_fetcher(ScanState *ss, TsFdwScanState *fsstate)
}
}
/*
* Row-by-row fetcher uses COPY statement that don't work with prepared
* statements. If this plan is parameterized, this means we'll have to
* revert to cursor fetcher.
*/
if (num_params > 0 && fsstate->planned_fetcher_type == RowByRowFetcherType)
{
if (ts_guc_remote_data_fetcher == AutoFetcherType)
{
fsstate->planned_fetcher_type = CursorFetcherType;
}
else
{
ereport(ERROR,
(errmsg("cannot use row-by-row fetcher because the plan is parameterized"),
errhint("Set \"timescaledb.remote_data_fetcher\" to \"cursor\" to explicitly "
"set the fetcher type or use \"auto\" to select the fetcher type "
"automatically.")));
}
}
if (fsstate->planned_fetcher_type == CursorFetcherType)
{
fetcher = cursor_fetcher_create_for_scan(fsstate->conn, fsstate->query, params, tf);

13
tsl/src/remote/row_by_row_fetcher.c
View File

@ -116,15 +116,18 @@ row_by_row_fetcher_send_fetch_request(DataFetcher *df)
fetcher->state.open = true;
PGresult *res = PQgetResult(remote_connection_get_pg_conn(fetcher->state.conn));
if (!res)
if (res == NULL)
{
elog(ERROR, "unexpected NULL response when starting COPY mode");
/* Shouldn't really happen but technically possible. */
TSConnectionError err;
remote_connection_get_error(fetcher->state.conn, &err);
remote_connection_error_elog(&err, ERROR);
}
if (PQresultStatus(res) != PGRES_COPY_OUT)
{
elog(ERROR,
"unexpected PQresult status %d when starting COPY mode",
PQresultStatus(res));
TSConnectionError err;
remote_connection_get_result_error(res, &err);
remote_connection_error_elog(&err, ERROR);
}
PQclear(res);

47
tsl/test/shared/expected/dist_fetcher_type.out
View File

@ -221,3 +221,50 @@ ORDER BY 1,2;
Sun Jan 01 08:01:00 2017 PST | 1 | 7.3
(2 rows)
-- Check that we don't use row-by-row fetcher for parameterized plans.
CREATE TABLE lookup (id SERIAL NOT NULL, key TEXT, val TEXT);
CREATE TABLE metric (ts TIMESTAMPTZ NOT NULL, val FLOAT8 NOT NULL, lookup_id INT NOT NULL);
SELECT 1 FROM create_distributed_hypertable('metric', 'ts');
?column?
1
(1 row)
INSERT INTO lookup (key, val) VALUES ('host', 'localhost');
INSERT INTO metric (ts, val, lookup_id) SELECT s.*, 3.14+1, 1
FROM generate_series('2021-08-17 00:00:00'::timestamp, '2021-08-17 00:59:59'::timestamp, '1 s'::interval) s;
SELECT
m.ts,
m.val
FROM metric m
WHERE
ARRAY[m.lookup_id] && (SELECT array_agg(l.id)::int[] FROM lookup l WHERE l.key = 'host' AND l.val = 'localhost')
AND m.ts BETWEEN '2021-08-17 00:00:00' AND '2021-08-17 01:00:00'
ORDER BY 1 DESC LIMIT 1;
ts | val
------------------------------+------
Tue Aug 17 00:59:59 2021 PDT | 4.14
(1 row)
SELECT
m.ts,
m.val
FROM metric m
WHERE
m.lookup_id = ANY((SELECT array_agg(l.id) FROM lookup l WHERE l.key = 'host' AND l.val = 'localhost')::int[])
AND m.ts BETWEEN '2021-08-17 00:00:00' AND '2021-08-17 01:00:00'
ORDER BY 1 DESC LIMIT 1;
ts | val
------------------------------+------
Tue Aug 17 00:59:59 2021 PDT | 4.14
(1 row)
SET timescaledb.remote_data_fetcher = 'rowbyrow';
SELECT
m.ts,
m.val
FROM metric m
WHERE
m.lookup_id = ANY((SELECT array_agg(l.id) FROM lookup l WHERE l.key = 'host' AND l.val = 'localhost')::int[])
AND m.ts BETWEEN '2021-08-17 00:00:00' AND '2021-08-17 01:00:00'
ORDER BY 1 DESC LIMIT 1;
ERROR: cannot use row-by-row fetcher because the plan is parameterized

37
tsl/test/shared/sql/dist_fetcher_type.sql
View File

@ -136,3 +136,40 @@ WHERE EXISTS (
(SELECT device_id FROM metrics_compressed limit 1 offset 3) >= ref_0.device
)
ORDER BY 1,2;
-- Check that we don't use row-by-row fetcher for parameterized plans.
CREATE TABLE lookup (id SERIAL NOT NULL, key TEXT, val TEXT);
CREATE TABLE metric (ts TIMESTAMPTZ NOT NULL, val FLOAT8 NOT NULL, lookup_id INT NOT NULL);
SELECT 1 FROM create_distributed_hypertable('metric', 'ts');
INSERT INTO lookup (key, val) VALUES ('host', 'localhost');
INSERT INTO metric (ts, val, lookup_id) SELECT s.*, 3.14+1, 1
FROM generate_series('2021-08-17 00:00:00'::timestamp, '2021-08-17 00:59:59'::timestamp, '1 s'::interval) s;
SELECT
m.ts,
m.val
FROM metric m
WHERE
ARRAY[m.lookup_id] && (SELECT array_agg(l.id)::int[] FROM lookup l WHERE l.key = 'host' AND l.val = 'localhost')
AND m.ts BETWEEN '2021-08-17 00:00:00' AND '2021-08-17 01:00:00'
ORDER BY 1 DESC LIMIT 1;
SELECT
m.ts,
m.val
FROM metric m
WHERE
m.lookup_id = ANY((SELECT array_agg(l.id) FROM lookup l WHERE l.key = 'host' AND l.val = 'localhost')::int[])
AND m.ts BETWEEN '2021-08-17 00:00:00' AND '2021-08-17 01:00:00'
ORDER BY 1 DESC LIMIT 1;
SET timescaledb.remote_data_fetcher = 'rowbyrow';
SELECT
m.ts,
m.val
FROM metric m
WHERE
m.lookup_id = ANY((SELECT array_agg(l.id) FROM lookup l WHERE l.key = 'host' AND l.val = 'localhost')::int[])
AND m.ts BETWEEN '2021-08-17 00:00:00' AND '2021-08-17 01:00:00'
ORDER BY 1 DESC LIMIT 1;