imranbohoran/express-sequelize

And example of express+sequelize+postgres

This example is setup to show a memory spike when using findOrCreate vs findCreateFind model operations exposed by sequelize.

When findOrCreate is used sequelize creates temporary functions to keep track of things if something goes wrong in a transaction. Under high load this has an impact on postgres where memory usage keeps increasing and at one point can cause a crash if postgres memory usage tips over allocated swap space. Using findCreateFind doesn't seem to have the same effect on postgres as it doesn't use transactions.

Running this example.

Setup the postgres container

Go into the postgres-docker-image folder

• Build the postgres docker image docker build -t postgres/9.4.4-express .

• Start a postgres container docker run --name express-sample-db -e POSTGRES_PASSWORD=supersecret -d -p 5432:5432 postgres/9.4.4-express

• This could also be done by pointing to a postgres setup of your own. Make sure the host and creds are updated accordingly.

Bring up the sample express app

Go into the express-example folder npm start

You should be able to access the app at http://localhost:3000/

Running some load against the app

Once the app is running pointed to a database (either external or docker container as described above) run some load to create users;

Go into the gatling folder ./run-create-user-load.sh

Now monitor postgres.

For a dockerised postgress; docker stats $(docker ps | awk '{if(NR>1) print $NF}')