explain.depesz.com

PostgreSQL's explain analyze made readable

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

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Optimization path:

Optimization(s) for this plan:

# exclusive inclusive rows x rows loops node
1. 0.002 0.066 ↑ 1.0 1 1

Limit (cost=40.50..40.50 rows=1 width=189) (actual time=0.064..0.066 rows=1 loops=1)

2. 0.008 0.064 ↑ 18.0 1 1

Sort (cost=40.50..40.54 rows=18 width=189) (actual time=0.064..0.064 rows=1 loops=1)

  • Sort Key: wifiaeroscouttagspositionhistory.watph_from DESC
  • Sort Method: top-N heapsort Memory: 25kB
3. 0.006 0.056 ↑ 1.0 18 1

Hash Join (cost=27.60..40.41 rows=18 width=189) (actual time=0.050..0.056 rows=18 loops=1)

  • Hash Cond: (wifiaeroscouttagspositionhistory.watph_wap_basemac = wifiaccesspoints.wap_basemac)
4. 0.005 0.042 ↑ 1.0 18 1

Hash Right Join (cost=26.47..39.20 rows=18 width=180) (actual time=0.039..0.042 rows=18 loops=1)

  • Hash Cond: (wifiaccesspointsassignmenthistory.wapah_basemac = wifiaeroscouttagspositionhistory.watph_wap_basemac)
5. 0.006 0.013 ↑ 8.0 1 1

Hash Right Join (cost=14.42..26.95 rows=8 width=164) (actual time=0.010..0.013 rows=1 loops=1)

  • Hash Cond: (nodeslogical.nl_id = wifiaccesspointsassignmenthistory.wapah_nl_id)
6. 0.003 0.003 ↑ 50.0 4 1

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

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
8. 0.002 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. 0.001 0.001 ↑ 8.0 1 1

Bitmap Index Scan on wapah_unique_active_logical (cost=0.00..4.18 rows=8 width=0) (actual time=0.001..0.001 rows=1 loops=1)

10. 0.003 0.024 ↑ 1.0 18 1

Hash (cost=11.82..11.82 rows=18 width=22) (actual time=0.024..0.024 rows=18 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
11. 0.015 0.021 ↑ 1.0 18 1

Bitmap Heap Scan on wifiaeroscouttagspositionhistory (cost=4.48..11.82 rows=18 width=22) (actual time=0.011..0.021 rows=18 loops=1)

  • Recheck Cond: (watph_wat_mac = '00:0c:cc:49:17:64'::macaddr)
  • Filter: (watph_wap_basemac IS NOT NULL)
  • Rows Removed by Filter: 8
  • Heap Blocks: exact=6
12. 0.006 0.006 ↑ 1.0 26 1

Bitmap Index Scan on watph_wat_mac_index (cost=0.00..4.48 rows=27 width=0) (actual time=0.006..0.006 rows=26 loops=1)

  • Index Cond: (watph_wat_mac = '00:0c:cc:49:17:64'::macaddr)
13. 0.003 0.008 ↑ 1.0 6 1

Hash (cost=1.06..1.06 rows=6 width=15) (actual time=0.008..0.008 rows=6 loops=1)

  • Buckets: 1024 Batches: 1 Memory Usage: 9kB
14. 0.005 0.005 ↑ 1.0 6 1

Seq Scan on wifiaccesspoints (cost=0.00..1.06 rows=6 width=15) (actual time=0.004..0.005 rows=6 loops=1)