Might be a chance on 9.0 in a couple of weeks, when I do an upgrade on one our
dev boxes.
Kevin I've now clustered the table. And the performance did increase quite a
bit. My only question is how often will I need to re-cluster the table, because
it comes at quite a cost. The setup I'm running will mean that 10,000 new rows
will be inserted, and 2,500 rows will be updated on this table each day.
Here is the new explain output once I have clustered on the
idx_crs_coordinate_revision_created index:
Subquery Scan t (cost=168227.04..173053.88 rows=743 width=205) (actual
time=392.586..946.879 rows=106299 loops=1)
Output: t.row_number, t._revision_created, t._revision_expired, t.id,
t.cos_id, t.nod_id, t.ort_type_1, t.ort_type_2, t.ort_type_3, t.status,
t.sdc_status, t.source, t.value1, t.value2, t.value3, t.wrk_id_created,
t.cor_id, t.audit_id
Filter: (t.row_number = 1)
-> WindowAgg (cost=168227.04..171197.40 rows=148518 width=86) (actual
time=392.577..834.477 rows=149557 loops=1)
Output: row_number() OVER (?),
table_version_crs_coordinate_revision._revision_created,
table_version_crs_coordinate_revision._revision_expired,
table_version_crs_coordinate_revision.id,
table_version_crs_coordinate_revision.cos_id,
table_version_crs_coordinate_revision.nod_id,
table_version_crs_coordinate_revision.ort_type_1,
table_version_crs_coordinate_revision.ort_type_2,
table_version_crs_coordinate_revision.ort_type_3,
table_version_crs_coordinate_revision.status,
table_version_crs_coordinate_revision.sdc_status,
table_version_crs_coordinate_revision.source,
table_version_crs_coordinate_revision.value1,
table_version_crs_coordinate_revision.value2,
table_version_crs_coordinate_revision.value3,
table_version_crs_coordinate_revision.wrk_id_created,
table_version_crs_coordinate_revision.cor_id,
table_version_crs_coordinate_revision.audit_id
-> Sort (cost=168227.04..168598.34 rows=148518 width=86) (actual
time=392.550..457.460 rows=149557 loops=1)
Output: table_version_crs_coordinate_revision._revision_created,
table_version_crs_coordinate_revision._revision_expired,
table_version_crs_coordinate_revision.id,
table_version_crs_coordinate_revision.cos_id,
table_version_crs_coordinate_revision.nod_id,
table_version_crs_coordinate_revision.ort_type_1,
table_version_crs_coordinate_revision.ort_type_2,
table_version_crs_coordinate_revision.ort_type_3,
table_version_crs_coordinate_revision.status,
table_version_crs_coordinate_revision.sdc_status,
table_version_crs_coordinate_revision.source,
table_version_crs_coordinate_revision.value1,
table_version_crs_coordinate_revision.value2,
table_version_crs_coordinate_revision.value3,
table_version_crs_coordinate_revision.wrk_id_created,
table_version_crs_coordinate_revision.cor_id,
table_version_crs_coordinate_revision.audit_id
Sort Key: table_version_crs_coordinate_revision.id,
table_version_crs_coordinate_revision._revision_created
Sort Method: quicksort Memory: 23960kB
-> Bitmap Heap Scan on table_version_crs_coordinate_revision
(cost=3215.29..155469.14 rows=148518 width=86) (actual time=38.808..196.993
rows=149557 loops=1)
Output:
table_version_crs_coordinate_revision._revision_created,
table_version_crs_coordinate_revision._revision_expired,
table_version_crs_coordinate_revision.id,
table_version_crs_coordinate_revision.cos_id,
table_version_crs_coordinate_revision.nod_id,
table_version_crs_coordinate_revision.ort_type_1,
table_version_crs_coordinate_revision.ort_type_2,
table_version_crs_coordinate_revision.ort_type_3,
table_version_crs_coordinate_revision.status,
table_version_crs_coordinate_revision.sdc_status,
table_version_crs_coordinate_revision.source,
table_version_crs_coordinate_revision.value1,
table_version_crs_coordinate_revision.value2,
table_version_crs_coordinate_revision.value3,
table_version_crs_coordinate_revision.wrk_id_created,
table_version_crs_coordinate_revision.cor_id,
table_version_crs_coordinate_revision.audit_id
Recheck Cond: (((_revision_expired > 16) AND
(_revision_expired <= 40)) OR ((_revision_created > 16) AND (_revision_created
<= 40)))
Filter: (((_revision_created <= 16) AND (_revision_expired
> 16) AND (_revision_expired <= 40)) OR ((_revision_created > 16) AND
(_revision_created <= 40)))
-> BitmapOr (cost=3215.29..3215.29 rows=149432 width=0)
(actual time=27.330..27.330 rows=0 loops=1)
-> Bitmap Index Scan on
idx_crs_coordinate_revision_expired (cost=0.00..2225.36 rows=106001 width=0)
(actual time=21.596..21.596 rows=110326 loops=1)
Index Cond: ((_revision_expired > 16) AND
(_revision_expired <= 40))
-> Bitmap Index Scan on
idx_crs_coordinate_revision_created (cost=0.00..915.67 rows=43432 width=0)
(actual time=5.728..5.728 rows=43258 loops=1)
Index Cond: ((_revision_created > 16) AND
(_revision_created <= 40))
Total runtime: 985.671 ms
Thanks heaps,
Jeremy
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