CODEWITHSUNDEEP
mongodbindexing
Kamilski81
Kamilski81

Reputation: 15107

How do I debug my mongodb indexes?

I have a search that take over 80 seconds on production, but only a second on my local (the data is almost identical). I am not sure what steps I can take next.

The query looks like:

@params = {search_field: 'kamil'}
User.only('username', 'email', 'name', 'role', 'utm_email').or({:"email" => /#{@params[:search_field]}/i},
                   {:"username" => /#{@params[:search_field]}/i},
                   {:"name" => /#{@params[:search_field]}/i}).explain()

My dev output of explain():

https://gist.github.com/kamilski81/827f9b363b0392cc87d9

My production output of explain():

https://gist.github.com/kamilski81/c0b07b838ddfbdb97c61

I am not really sure where to take it from here, as the outputs look very similar to me. Dev is running mongodb-2.4.9 and production is running mongodb-2.4.10

Upvotes: 2

Views: 484

Answers (1)

i3arnon
i3arnon

Reputation: 116518

You can use the profiler. It would create a collection with a document for every operation above a threshold (default 100 ms).

You should turn it on using the shell, and set the threshold to about 60 seconds:

db.setProfilingLevel(1,60000)

Execute the operation and find the relevant document in the collection and you can see which index is being used, how much time you were waiting on a lock, how many documents did MongoDB scan and so forth.

More about the profiler here

Upvotes: 2

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