explain.depesz.com

PostgreSQL's explain analyze made readable

Result: Z4Wx : Optimization for: Optimization for: Optimization for: plan #SD18; plan #wb5W; plan #QfXa

Settings

Optimization path:

Optimization(s) for this plan:

# exclusive inclusive rows x rows loops node
1. 0.003 0.081 ↑ 1.0 1 1

Limit (cost=40.32..40.32 rows=1 width=189) (actual time=0.079..0.081 rows=1 loops=1)

2. 0.009 0.078 ↑ 18.0 1 1

Sort (cost=40.32..40.36 rows=18 width=189) (actual time=0.078..0.078 rows=1 loops=1)

  • Sort Key: wifiaeroscouttagspositionhistory.watph_from DESC
  • Sort Method: top-N heapsort Memory: 25kB
3. 0.007 0.069 ↑ 1.0 18 1

Hash Join (cost=27.42..40.23 rows=18 width=189) (actual time=0.062..0.069 rows=18 loops=1)

  • Hash Cond: (wifiaeroscouttagspositionhistory.watph_wap_basemac = wifiaccesspoints.wap_basemac)
4. 0.006 0.053 ↑ 1.0 18 1

Hash Right Join (cost=26.29..39.02 rows=18 width=180) (actual time=0.050..0.053 rows=18 loops=1)

  • Hash Cond: (wifiaccesspointsassignmenthistory.wapah_basemac = wifiaeroscouttagspositionhistory.watph_wap_basemac)
5. 0.007 0.015 ↑ 8.0 1 1

Hash Right Join (cost=14.42..26.95 rows=8 width=164) (actual time=0.012..0.015 rows=1 loops=1)

  • Hash Cond: (nodeslogical.nl_id = wifiaccesspointsassignmenthistory.wapah_nl_id)
6. 0.004 0.004 ↑ 50.0 4 1

Seq Scan on nodeslogical (cost=0.00..12.00 rows=200 width=158) (actual time=0.003..0.004 rows=4 loops=1)

7. 0.001 0.004 ↑ 8.0 1 1

Hash (cost=14.32..14.32 rows=8 width=10) (actual time=0.004..0.004 rows=1 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
8. 0.001 0.003 ↑ 8.0 1 1

Bitmap Heap Scan on wifiaccesspointsassignmenthistory (cost=4.19..14.32 rows=8 width=10) (actual time=0.003..0.003 rows=1 loops=1)

  • Recheck Cond: (wapah_end IS NULL)
  • Heap Blocks: exact=1
9. 0.002 0.002 ↑ 8.0 1 1

Bitmap Index Scan on wapah_unique_active_logical (cost=0.00..4.18 rows=8 width=0) (actual time=0.002..0.002 rows=1 loops=1)

10. 0.004 0.032 ↑ 1.0 18 1

Hash (cost=11.64..11.64 rows=18 width=22) (actual time=0.032..0.032 rows=18 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
11. 0.014 0.028 ↑ 1.0 18 1

Bitmap Heap Scan on wifiaeroscouttagspositionhistory (cost=4.41..11.64 rows=18 width=22) (actual time=0.018..0.028 rows=18 loops=1)

  • Recheck Cond: ((watph_wat_mac = '00:0c:cc:49:17:64'::macaddr) AND (watph_wap_basemac IS NOT NULL))
  • Heap Blocks: exact=6
12. 0.014 0.014 ↑ 1.0 18 1

Bitmap Index Scan on watph_wat_mac_index (cost=0.00..4.41 rows=18 width=0) (actual time=0.014..0.014 rows=18 loops=1)

  • Index Cond: (watph_wat_mac = '00:0c:cc:49:17:64'::macaddr)
13. 0.003 0.009 ↑ 1.0 6 1

Hash (cost=1.06..1.06 rows=6 width=15) (actual time=0.009..0.009 rows=6 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
14. 0.006 0.006 ↑ 1.0 6 1

Seq Scan on wifiaccesspoints (cost=0.00..1.06 rows=6 width=15) (actual time=0.004..0.006 rows=6 loops=1)