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887d0271e8
enable index backward scan and backward scan of chunk data by checking if the compress_orderby columns can satisfy the required sort order
20 lines
1.3 KiB
SQL
20 lines
1.3 KiB
SQL
-- This file and its contents are licensed under the Timescale License.
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-- Please see the included NOTICE for copyright information and
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-- LICENSE-TIMESCALE for a copy of the license.
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SET work_mem TO '50MB';
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---Lets test for index backward scans instead of seq scans ------------
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-- for ordered append tests on compressed chunks we need a hypertable with time as compress_orderby column
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-- should not have ordered DecompressChunk path because segmentby columns are not part of pathkeys
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:PREFIX select * from ( SELECT * FROM metrics_ordered_idx ORDER BY time DESC LIMIT 10 ) as q order by 1,2,3,4;
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-- should have ordered DecompressChunk path because segmentby columns have equality constraints
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:PREFIX select * from (SELECT * FROM metrics_ordered_idx WHERE device_id = 3 AND device_id_peer = 3 ORDER BY time DESC LIMIT 10) as q order by 1, 2, 3, 4;
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:PREFIX SELECT DISTINCT ON (d.device_id) * FROM metrics_ordered_idx d INNER JOIN LATERAL (SELECT * FROM metrics_ordered_idx m WHERE m.device_id=d.device_id AND m.device_id_peer = 3 ORDER BY time DESC LIMIT 1 ) m ON m.device_id_peer = d.device_id_peer;
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:PREFIX SELECT d.device_id, m.time, m.time
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FROM metrics_ordered_idx d INNER JOIN LATERAL (SELECT * FROM metrics_ordered_idx m WHERE m.device_id=d.device_id AND m.device_id_peer = 3 ORDER BY time DESC LIMIT 1 ) m ON m.device_id_peer = d.device_id_peer;
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