Can dgraph support execute plan?

Users Dgraph
1

Just like explain in SQL or other database system.
Can dgraph support query plan to show the cost of io or cpu of each function?
A query may be like this:

query {
   q(func: has(name)){
    uid
   }
}

The grammar I expect may like this:

explain {
 q(func: has(name)){
    uid
   }
}

Just replace the keyword query to explain.

1 Like
2

This is in our roadmap. But you can use Jaeger to get details about each operation if you are familiar with tracing.

3

Bearing in mind that using Jaeger, you will need to execute the query first. EXPLAIN in SQL doesn’t. It just prints out (in our equivalent) the subgraph and workers list.

4

thank you , I will try it later.

5

okay ,thanks .
I will try it later

6

Hi Michel,
I set up my Jaeger.
However, I can’t find any logs about Server.Query.

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7

I’m pretty sure that you have traces of the query operation. But now, I don’t remember it from the top of my mind what are the values to follow. Tomorrow I can take a look (It is late here).

8

okay, thank you

9

Hey, I just find out (with @dmai’s help) what was the issue (I hope). I was getting the same behavior as yours on my machine. Using a Jaeger Darwin Binary. The issue is that Dgraph sends by default a sampling rate of 0.01 (1%) so you should increase it to 1. Which means 100%.

e.g:

dgraph alpha --jaeger.collector=http://localhost:14268 --trace=1

Now you should be able to see all operations traces right away.

Cheers.

11

thank you