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9f984ba6d2
Commit 16fa9b2b30 introduced a faster way to build GiST indexes, by
sorting all the data. This commit adds the sortsupport functions needed
to make use of that feature for btree_gist.
Author: Andrey Borodin
Discussion: https://www.postgresql.org/message-id/2F3F7265-0D22-44DB-AD71-8554C743D943@yandex-team.ru
99 lines
2.2 KiB
Plaintext
99 lines
2.2 KiB
Plaintext
-- float8 check
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CREATE TABLE float8tmp (a float8);
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\copy float8tmp from 'data/float8.data'
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SET enable_seqscan=on;
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SELECT count(*) FROM float8tmp WHERE a < -1890.0;
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count
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-------
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237
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a <= -1890.0;
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count
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-------
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238
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a = -1890.0;
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count
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-------
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1
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a >= -1890.0;
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count
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-------
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307
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a > -1890.0;
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count
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-------
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306
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(1 row)
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SELECT a, a <-> '-1890.0' FROM float8tmp ORDER BY a <-> '-1890.0' LIMIT 3;
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a | ?column?
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--------------+--------------------
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-1890 | 0
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-2003.634512 | 113.63451200000009
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-1769.73634 | 120.26366000000007
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(3 rows)
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SET client_min_messages = DEBUG1;
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CREATE INDEX float8idx ON float8tmp USING gist ( a );
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DEBUG: building index "float8idx" on table "float8tmp" serially
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DEBUG: using sorted GiST build
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CREATE INDEX float8idx_b ON float8tmp USING gist ( a ) WITH (buffering=on);
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DEBUG: building index "float8idx_b" on table "float8tmp" serially
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DROP INDEX float8idx_b;
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RESET client_min_messages;
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SET enable_seqscan=off;
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SELECT count(*) FROM float8tmp WHERE a < -1890.0::float8;
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count
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-------
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237
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a <= -1890.0::float8;
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count
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-------
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238
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a = -1890.0::float8;
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count
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-------
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1
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a >= -1890.0::float8;
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count
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-------
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307
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(1 row)
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SELECT count(*) FROM float8tmp WHERE a > -1890.0::float8;
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count
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-------
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306
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(1 row)
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EXPLAIN (COSTS OFF)
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SELECT a, a <-> '-1890.0' FROM float8tmp ORDER BY a <-> '-1890.0' LIMIT 3;
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QUERY PLAN
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-----------------------------------------------------
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Limit
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-> Index Only Scan using float8idx on float8tmp
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Order By: (a <-> '-1890'::double precision)
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(3 rows)
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SELECT a, a <-> '-1890.0' FROM float8tmp ORDER BY a <-> '-1890.0' LIMIT 3;
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a | ?column?
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--------------+--------------------
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-1890 | 0
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-2003.634512 | 113.63451200000009
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-1769.73634 | 120.26366000000007
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(3 rows)
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