@@ -210,11 +210,11 @@ SELECT 10000000
210210=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
211211 QUERY PLAN
212212-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-&zwsp;-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-
213- Seq Scan on tbloom (cost=0.00..2137.14 rows=3 width=24) (actual time=15.480..15.480 rows=0 loops=1)
213+ Seq Scan on tbloom (cost=0.00..2137.14 rows=3 width=24) (actual time=16.971..16.971 rows=0 loops=1)
214214 Filter: ((i2 = 898732) AND (i5 = 123451))
215215 Rows Removed by Filter: 100000
216- Planning Time: 0.340 ms
217- Execution Time: 15.501 ms
216+ Planning Time: 0.346 ms
217+ Execution Time: 16.988 ms
218218(5 rows)
219219</programlisting>
220220 </para>
@@ -225,11 +225,11 @@ ____________________________________________________________________________-->
225225=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
226226 QUERY PLAN
227227-------------------------------------------------------------------&zwsp;-----------------------------------
228- Seq Scan on tbloom (cost=0.00..2137.14 rows=3 width=24) (actual time=15.480..15.480 rows=0 loops=1)
228+ Seq Scan on tbloom (cost=0.00..2137.14 rows=3 width=24) (actual time=16.971..16.971 rows=0 loops=1)
229229 Filter: ((i2 = 898732) AND (i5 = 123451))
230230 Rows Removed by Filter: 100000
231- Planning Time: 0.340 ms
232- Execution Time: 15.501 ms
231+ Planning Time: 0.346 ms
232+ Execution Time: 16.988 ms
233233(5 rows)
234234</programlisting>
235235 </para>
@@ -249,11 +249,11 @@ CREATE INDEX
249249=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
250250 QUERY PLAN
251251-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-&zwsp;-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-
252- Seq Scan on tbloom (cost=0.00..2137.00 rows=2 width=24) (actual time=12.604 ..12.604 rows=0 loops=1)
252+ Seq Scan on tbloom (cost=0.00..2137.00 rows=2 width=24) (actual time=12.805 ..12.805 rows=0 loops=1)
253253 Filter: ((i2 = 898732) AND (i5 = 123451))
254254 Rows Removed by Filter: 100000
255- Planning Time: 0.155 ms
256- Execution Time: 12.617 ms
255+ Planning Time: 0.138 ms
256+ Execution Time: 12.817 ms
257257(5 rows)
258258</programlisting>
259259 </para>
@@ -271,11 +271,11 @@ CREATE INDEX
271271=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
272272 QUERY PLAN
273273-------------------------------------------------------------------&zwsp;-----------------------------------
274- Seq Scan on tbloom (cost=0.00..2137.00 rows=2 width=24) (actual time=12.604 ..12.604 rows=0 loops=1)
274+ Seq Scan on tbloom (cost=0.00..2137.00 rows=2 width=24) (actual time=12.805 ..12.805 rows=0 loops=1)
275275 Filter: ((i2 = 898732) AND (i5 = 123451))
276276 Rows Removed by Filter: 100000
277- Planning Time: 0.155 ms
278- Execution Time: 12.617 ms
277+ Planning Time: 0.138 ms
278+ Execution Time: 12.817 ms
279279(5 rows)
280280</programlisting>
281281 </para>
@@ -295,14 +295,14 @@ CREATE INDEX
295295=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
296296 QUERY PLAN
297297-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-&zwsp;-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−
298- Bitmap Heap Scan on tbloom (cost=1792.00..1799.69 rows=2 width=24) (actual time=0.384 ..0.384 rows=0 loops=1)
298+ Bitmap Heap Scan on tbloom (cost=1792.00..1799.69 rows=2 width=24) (actual time=0.388 ..0.388 rows=0 loops=1)
299299 Recheck Cond: ((i2 = 898732) AND (i5 = 123451))
300- Rows Removed by Index Recheck: 26
301- Heap Blocks: exact=26
302- -> Bitmap Index Scan on bloomidx (cost=0.00..1792.00 rows=2 width=0) (actual time=0.350 ..0.350 rows=26 loops=1)
300+ Rows Removed by Index Recheck: 29
301+ Heap Blocks: exact=28
302+ -> Bitmap Index Scan on bloomidx (cost=0.00..1792.00 rows=2 width=0) (actual time=0.356 ..0.356 rows=29 loops=1)
303303 Index Cond: ((i2 = 898732) AND (i5 = 123451))
304- Planning Time: 0.122 ms
305- Execution Time: 0.407 ms
304+ Planning Time: 0.099 ms
305+ Execution Time: 0.408 ms
306306(8 rows)
307307</programlisting>
308308 </para>
@@ -320,14 +320,14 @@ CREATE INDEX
320320=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
321321 QUERY PLAN
322322-------------------------------------------------------------------&zwsp;--------------------------------------------------
323- Bitmap Heap Scan on tbloom (cost=1792.00..1799.69 rows=2 width=24) (actual time=0.384 ..0.384 rows=0 loops=1)
323+ Bitmap Heap Scan on tbloom (cost=1792.00..1799.69 rows=2 width=24) (actual time=0.388 ..0.388 rows=0 loops=1)
324324 Recheck Cond: ((i2 = 898732) AND (i5 = 123451))
325- Rows Removed by Index Recheck: 26
326- Heap Blocks: exact=26
327- -> Bitmap Index Scan on bloomidx (cost=0.00..1792.00 rows=2 width=0) (actual time=0.350 ..0.350 rows=26 loops=1)
325+ Rows Removed by Index Recheck: 29
326+ Heap Blocks: exact=28
327+ -> Bitmap Index Scan on bloomidx (cost=0.00..1792.00 rows=2 width=0) (actual time=0.356 ..0.356 rows=29 loops=1)
328328 Index Cond: ((i2 = 898732) AND (i5 = 123451))
329- Planning Time: 0.122 ms
330- Execution Time: 0.407 ms
329+ Planning Time: 0.099 ms
330+ Execution Time: 0.408 ms
331331(8 rows)
332332</programlisting>
333333 </para>
@@ -354,15 +354,15 @@ CREATE INDEX
354354=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
355355 QUERY PLAN
356356-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-&zwsp;-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−-−
357- Bitmap Heap Scan on tbloom (cost=24.34..32.03 rows=2 width=24) (actual time=0.032 ..0.033 rows=0 loops=1)
357+ Bitmap Heap Scan on tbloom (cost=24.34..32.03 rows=2 width=24) (actual time=0.028 ..0.029 rows=0 loops=1)
358358 Recheck Cond: ((i5 = 123451) AND (i2 = 898732))
359- -> BitmapAnd (cost=24.34..24.34 rows=2 width=0) (actual time=0.029 ..0.030 rows=0 loops=1)
360- -> Bitmap Index Scan on btreeidx5 (cost=0.00..12.04 rows=500 width=0) (actual time=0.029 ..0.029 rows=0 loops=1)
359+ -> BitmapAnd (cost=24.34..24.34 rows=2 width=0) (actual time=0.027 ..0.027 rows=0 loops=1)
360+ -> Bitmap Index Scan on btreeidx5 (cost=0.00..12.04 rows=500 width=0) (actual time=0.026 ..0.026 rows=0 loops=1)
361361 Index Cond: (i5 = 123451)
362362 -> Bitmap Index Scan on btreeidx2 (cost=0.00..12.04 rows=500 width=0) (never executed)
363363 Index Cond: (i2 = 898732)
364- Planning Time: 0.537 ms
365- Execution Time: 0.064 ms
364+ Planning Time: 0.491 ms
365+ Execution Time: 0.055 ms
366366(9 rows)
367367</programlisting>
368368 Although this query runs much faster than with either of the single
@@ -389,15 +389,15 @@ CREATE INDEX
389389=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 = 123451;
390390 QUERY PLAN
391391-------------------------------------------------------------------&zwsp;--------------------------------------------------------
392- Bitmap Heap Scan on tbloom (cost=24.34..32.03 rows=2 width=24) (actual time=0.032 ..0.033 rows=0 loops=1)
392+ Bitmap Heap Scan on tbloom (cost=24.34..32.03 rows=2 width=24) (actual time=0.028 ..0.029 rows=0 loops=1)
393393 Recheck Cond: ((i5 = 123451) AND (i2 = 898732))
394- -> BitmapAnd (cost=24.34..24.34 rows=2 width=0) (actual time=0.029 ..0.030 rows=0 loops=1)
395- -> Bitmap Index Scan on btreeidx5 (cost=0.00..12.04 rows=500 width=0) (actual time=0.029 ..0.029 rows=0 loops=1)
394+ -> BitmapAnd (cost=24.34..24.34 rows=2 width=0) (actual time=0.027 ..0.027 rows=0 loops=1)
395+ -> Bitmap Index Scan on btreeidx5 (cost=0.00..12.04 rows=500 width=0) (actual time=0.026 ..0.026 rows=0 loops=1)
396396 Index Cond: (i5 = 123451)
397397 -> Bitmap Index Scan on btreeidx2 (cost=0.00..12.04 rows=500 width=0) (never executed)
398398 Index Cond: (i2 = 898732)
399- Planning Time: 0.537 ms
400- Execution Time: 0.064 ms
399+ Planning Time: 0.491 ms
400+ Execution Time: 0.055 ms
401401(9 rows)
402402</programlisting>
403403 尽管这个查询运行起来比在其中任一单个索引上都快，但是我们在索引尺寸上付出了代价。
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