explain.depesz.com

PostgreSQL's explain analyze made readable

Result: yt8n : Optimization for: plan #C1IH

Settings

Optimization path:

# exclusive inclusive rows x rows loops node
1. 0.003 0.135 ↑ 1.0 1 1

Limit (cost=66.90..66.90 rows=1 width=185) (actual time=0.133..0.135 rows=1 loops=1)

2. 0.012 0.132 ↑ 13.0 1 1

Sort (cost=66.90..66.93 rows=13 width=185) (actual time=0.132..0.132 rows=1 loops=1)

  • Sort Key: wifiaeroscouttagspositionhistory.watph_from DESC
  • Sort Method: top-N heapsort Memory: 25kB
3. 0.018 0.120 ↑ 1.0 13 1

Hash Left Join (cost=34.55..66.83 rows=13 width=185) (actual time=0.097..0.120 rows=13 loops=1)

  • Hash Cond: (wifiaccesspointsassignmenthistory.wapah_basemac = wifiaccesspoints.wap_basemac)
4. 0.010 0.071 ↑ 1.0 13 1

Hash Left Join (cost=31.43..63.69 rows=13 width=182) (actual time=0.052..0.071 rows=13 loops=1)

  • Hash Cond: (wifiaeroscouttagspositionhistory.watph_wap_basemac = wifiaccesspointsassignmenthistory.wapah_basemac)
5. 0.019 0.031 ↑ 1.0 13 1

Bitmap Heap Scan on wifiaeroscouttagspositionhistory (cost=4.38..36.58 rows=13 width=22) (actual time=0.018..0.031 rows=13 loops=1)

  • Recheck Cond: (watph_wat_mac = '00:0c:cc:4f:ea:87'::macaddr)
  • Heap Blocks: exact=6
6. 0.012 0.012 ↑ 1.0 13 1

Bitmap Index Scan on watph_wat_mac_index (cost=0.00..4.38 rows=13 width=0) (actual time=0.012..0.012 rows=13 loops=1)

  • Index Cond: (watph_wat_mac = '00:0c:cc:4f:ea:87'::macaddr)
7. 0.002 0.030 ↑ 4.0 2 1

Hash (cost=26.95..26.95 rows=8 width=160) (actual time=0.030..0.030 rows=2 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
8. 0.013 0.028 ↑ 4.0 2 1

Hash Right Join (cost=14.42..26.95 rows=8 width=160) (actual time=0.023..0.028 rows=2 loops=1)

  • Hash Cond: (nodeslogical.nl_id = wifiaccesspointsassignmenthistory.wapah_nl_id)
9. 0.005 0.005 ↑ 40.0 5 1

Seq Scan on nodeslogical (cost=0.00..12.00 rows=200 width=158) (actual time=0.004..0.005 rows=5 loops=1)

10. 0.004 0.010 ↑ 4.0 2 1

Hash (cost=14.32..14.32 rows=8 width=10) (actual time=0.009..0.010 rows=2 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
11. 0.004 0.006 ↑ 4.0 2 1

Bitmap Heap Scan on wifiaccesspointsassignmenthistory (cost=4.19..14.32 rows=8 width=10) (actual time=0.005..0.006 rows=2 loops=1)

  • Recheck Cond: (wapah_end IS NULL)
  • Heap Blocks: exact=1
12. 0.002 0.002 ↑ 4.0 2 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=2 loops=1)

13. 0.010 0.031 ↑ 1.0 5 1

Hash (cost=3.05..3.05 rows=5 width=15) (actual time=0.031..0.031 rows=5 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
14. 0.021 0.021 ↑ 1.0 5 1

Seq Scan on wifiaccesspoints (cost=0.00..3.05 rows=5 width=15) (actual time=0.003..0.021 rows=5 loops=1)