inserting is very very slow about mongodb HOT 8 CLOSED

Victor looked into this but couldn't figure it out.

• There is no 40ms lag on OS X
• There is no 40ms lag when opening a pipe
• There is a 40ms lag when re-using a pipe
• resource-pool and System.IO.Pool have no effect
• The delay is not caused by CPU usage, but by blocking

from mongodb.

I just tested that Openning many connections and using resource-pool to manage them to insert records concurrently would reduce the overall latence. In fact with 100 connections in a pool, the running to reduce from 40s to 0.7s.

from mongodb.

If you open a new connection, you don't see the 40ms delay. So you should save 4 seconds. Timings are machine dependent though. Yours may be a little slower.

from mongodb.

Hello,

Is there any news about the performance issues?

I'm currently trying to build some simple read-only web service on top of a MongoDB database but the response times are really bad.

I tried some benchmarking : https://gist.github.com/Herzult/56226dd23d8692d5ac88

from mongodb.

no news. You could check to see if anything improves with 7.10

from mongodb.

I noticed that the driver is much faster when we don't reuse the existing connection to the database. Here is an example:

This code is faster:

forM_ docs $ \doc -> do
      pipe <- M.connect (M.host "127.0.0.1")
      vid <- M.access pipe M.master "mongodb-haskell-test" $ M.insert "bigCollection" doc
      putStrLn $ show vid
      M.close pipe

Than this code:

pipe <- M.connect (M.host "127.0.0.1")

forM_ docs $ \doc -> do  
      vid <- M.access pipe M.master "mongodb-haskell-test" $ M.insert "bigCollection" doc
      putStrLn $ show vid

M.close pipe

The first code takes only 2 sec to run. The second piece of code takes up to 4 minutes to run.
I'm researching this issue.

from mongodb.

Another piece of finding is that unconfirmed writes are much faster(thank you cap) even when we reuse the same connection. So, since unconfirmed writes and confirmed writes one per connection are much faster than many confirmed writes with one connection I can conclude that something is wrong with the queue of replies. Looking further into it...

from mongodb.

I'm marking this issue as resolved.

from mongodb.