explain.depesz.com

PostgreSQL's explain analyze made readable

Result: ZjK0

Settings
# exclusive inclusive rows x rows loops node
1. 0.333 236.616 ↓ 2.8 79 1

GroupAggregate (cost=7,233.20..7,234.11 rows=28 width=124) (actual time=236.289..236.616 rows=79 loops=1)

  • Group Key: t.attribute_name, t."timestamp
2. 0.127 236.283 ↓ 4.2 117 1

Sort (cost=7,233.20..7,233.27 rows=28 width=58) (actual time=236.259..236.283 rows=117 loops=1)

  • Sort Key: t.attribute_name, t."timestamp
  • Sort Method: quicksort Memory: 37kB
3. 0.088 236.156 ↓ 4.2 117 1

Nested Loop (cost=6,797.16..7,232.53 rows=28 width=58) (actual time=235.024..236.156 rows=117 loops=1)

4. 0.000 235.278 ↓ 1.6 79 1

Finalize GroupAggregate (cost=6,796.73..6,809.40 rows=50 width=28) (actual time=234.992..235.278 rows=79 loops=1)

  • Group Key: telemetry_old.attribute_name
5. 9.648 236.411 ↓ 2.0 197 1

Gather Merge (cost=6,796.73..6,808.40 rows=100 width=28) (actual time=234.985..236.411 rows=197 loops=1)

  • Workers Planned: 2
  • Workers Launched: 2
6. 0.234 226.763 ↓ 1.3 66 3 / 3

Sort (cost=5,796.71..5,796.84 rows=50 width=28) (actual time=226.749..226.763 rows=66 loops=3)

  • Sort Key: telemetry_old.attribute_name
  • Sort Method: quicksort Memory: 29kB
  • Worker 0: Sort Method: quicksort Memory: 30kB
  • Worker 1: Sort Method: quicksort Memory: 29kB
7. 155.408 226.529 ↓ 1.3 66 3 / 3

Partial HashAggregate (cost=5,794.80..5,795.30 rows=50 width=28) (actual time=226.510..226.529 rows=66 loops=3)

  • Group Key: telemetry_old.attribute_name
8. 71.121 71.121 ↑ 1.2 118,016 3 / 3

Parallel Seq Scan on telemetry_old (cost=0.00..5,057.20 rows=147,520 width=28) (actual time=0.005..71.121 rows=118,016 loops=3)

9. 0.790 0.790 ↑ 1.0 1 79

Index Scan using telemetry_attribute_name_timestamp_idx on telemetry_old t (cost=0.42..8.44 rows=1 width=58) (actual time=0.009..0.010 rows=1 loops=79)

  • Index Cond: (((attribute_name)::text = (telemetry_old.attribute_name)::text) AND ("timestamp" = (max(telemetry_old."timestamp"))))
Planning time : 0.306 ms
Execution time : 237.969 ms