pev2
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dalibo
Compare plans
We have more and more customers asking us why this plan is better than another one. In a nutshell, they want to compare the two plans, and it's pretty easy if the plans are small. But we've got bigger and bigger plans now. The two plans I have to compare today have 173/175 nodes. I'll do it manually as I have no other choice right now, but I would love to have the possibility with PEV2 to compare trees. What I'm mostly interested in is node types: did the planner replace a merge join with a hash join? did it replace a seq scan with a some kind of index scan? or a sort with an index scan? etc. I'm also interested in the order of the joins: did the planner choose to join A and B, and then the result with C, or B with C and then the result with A? did that order change between the two plans? I'm also interested with changes of object. It may still do an indexscan but with a different one.
Anyway. I think having a way to compare two plans will be more and more important these days with the larger plans we get.
I'd love too.
I suppose that Pierre would love to have a few examples to test some algorithms and how we would like the differences to show up.
BTW : duplicate bug of #377 ?
Definitely a duplicate. I spent quite some time looking for such a ticket, without finding it. Sorry.