explain.depesz.com

PostgreSQL's explain analyze made readable

Result: SxEh : OSM Jefferson County Reduced - Tree Count Spill to Disk

Settings
# exclusive inclusive rows x rows loops node
1. 528.265 3,325.149 ↑ 1.0 1 1

GroupAggregate (cost=863.61..864.69 rows=1 width=6,536) (actual time=3,325.149..3,325.149 rows=1 loops=1)

  • Group Key: c.osm_id, c.name, c.way
  • Buffers: shared hit=1091, temp read=28609 written=28646
2. 2,286.100 2,796.884 ↓ 427.4 36,757 1

Sort (cost=863.61..863.82 rows=86 width=6,536) (actual time=1,780.696..2,796.884 rows=36,757 loops=1)

  • Sort Key: c.osm_id, c.way
  • Sort Method: external merge Disk: 137128kB
  • Buffers: shared hit=1091, temp read=28609 written=28646
3. 4.762 510.784 ↓ 427.4 36,757 1

Nested Loop (cost=10.28..860.84 rows=86 width=6,536) (actual time=16.468..510.784 rows=36,757 loops=1)

  • Buffers: shared hit=1091
4. 0.063 0.063 ↑ 1.0 1 1

Seq Scan on county_polygon c (cost=0.00..18.76 rows=1 width=6,528) (actual time=0.058..0.063 rows=1 loops=1)

  • Filter: (name = 'Jefferson County'::text)
  • Rows Removed by Filter: 60
  • Buffers: shared hit=18
5. 490.001 505.959 ↓ 427.4 36,757 1

Bitmap Heap Scan on natural_point n (cost=10.28..841.22 rows=86 width=40) (actual time=16.402..505.959 rows=36,757 loops=1)

  • Recheck Cond: (c.way ~ way)
  • Filter: (("natural" = 'tree'::text) AND _st_contains(c.way, way))
  • Rows Removed by Filter: 23405
  • Heap Blocks: exact=628
  • Buffers: shared hit=1073
6. 15.958 15.958 ↓ 228.8 60,162 1

Bitmap Index Scan on gix_osm_natural_point (cost=0.00..10.26 rows=263 width=0) (actual time=15.958..15.958 rows=60,162 loops=1)

  • Index Cond: (c.way ~ way)
  • Buffers: shared hit=445