CODEWITHSUNDEEP
node.jspostgresqlsequelize.jsamazon-rds
Apoorv Kesharwani
Apoorv Kesharwani

Reputation: 377

Disparity in max connection pool size in sequelize and connections shown in the RDS management console

I am using postgres 9.5 on AWS RDS as the database and Sequelize as the ORM with node.js. The max_connections at the DB is 1660 while the max connection pool size at Sequelize is 600. Even at higher loads(~ 600 queries per second), which is evidenced by the Resource Request Timeout Error at Sequelize, the management console for AWS RDS shows the count of DB connections to be 10.

I want to ask if DB connections in the RDS console mean the same thing as the connection for which limits are configured in max_connections in RDS and max connection pool size in Sequelize.

If they are the same, then why doesn't the RDS console show more connections being used during the above mentioned times of higher load?

Upvotes: 0

Views: 1046

Answers (1)

jjanes
jjanes

Reputation: 44363

I want to ask if DB connections in the RDS console mean the same thing as the connection for which limits are configured in max_connections in RDS and max connection pool size in Sequelize.

Yes, DB connections means the same type of connection on which max_connections is setting a limit. However, the RDS console value is laggy. If the spike in connections is only transient, they might not show up at all, and if they show up it will be after the fact. Even if I were using RDS for my production data, I'd still set up a local database for testing things like this, as it would be easier to monitor in real time and in greater depth than provided by RDS. I don't know enough about Sequelize to say if it is the same thing as what "max connection pool size" refers to.

If they are the same, then why doesn't the RDS console show more connections being used during the above mentioned times of higher load?

Either they are there but you can't see them in the laggy console, or Sequelize isn't actually spawning them. Are there entries in the database log files?

Anyway, why do you want this? Your database doesn't have 600 CPUs. And probably doesn't have 600 independent IO channels, either. All you're going to do is goad your concurrent connections into fighting against each other for resources, and make your overall throughput lower due to contention on spinlocks or LWLocks.

Upvotes: 0

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