Postgres EXPLAIN Visualizer (Pev)
3 |4 | Pev is designed to make 5 | Postgres query plans easier to grok. It displays a plan as a tree, with each node representing a step that takes in a row set 6 | and produces another. Pev can show you a number of useful things:
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- overall plan stats 9 |
- individual node stats (duration, row size, cost) 10 |
- explanation of what each node does 11 |
- outlier nodes 12 |
- graph of a specific metric (like cost) for all nodes 13 |
- for some nodes, highlighted part of the query which corresponds to the node 14 |
You can tweak display options using the menu on the right.
17 | 18 |Usage tips
19 |Pev currently accepts only JSON formatted plans. In fact, the get the most out of it,
20 | I recommend generating a query plan using the following line:
21 | EXPLAIN (ANALYZE, COSTS, VERBOSE, BUFFERS, FORMAT JSON). I also recommend submitting a (decently formatted)
22 | SQL query that generated the plan. Doing so will make Pev more useful.
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Pev will remember the plans you analyzed. They are stored locally and are not submitted to me. This is good 26 | because no one but you will see your queries. It's also bad because you can't share them with others.
27 | 28 |Acknowledgements
29 |Pev was inspired and heavily influenced by the excellent explain.depesz.com. Both the 30 | tool and the corresponding help files are a great resource to learn about Postgres and its planner. 31 |
32 | 33 |Help me improve Pev
34 |If you want to help, there are multiple ways to contribute:
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- give me your plans - I need more test cases for the layout 37 |
- add descriptions for missing node types (especially ones from newer versions of Postgres) 38 |
- contribute to the code on github 39 |