amazon ec2 - Max connection pool size and autoscaling group -


in sequelize.js should configure max connection pool size (default 5). don't know how deal configuration work on autoscaling platform in aws.

the aurora db cluster on r3.2xlarge allows 2000 max connections per read replica (you can running select @@max_connections;).

the problem don't know should right configuration each server hosted on our ec2s. should right max connection pool size don't know how many servers launched autoscaling group? normally, db max_connections value should divided number of connection pools (one server), don't know how many server instantiated @ end.

our concurrent users count estimated between 50000 , 75000 concurrent users @ our release date.

did previous experience kind of situation?

it has been 6 weeks since asked, since got involved in thought share experience.

the answer various based on how application works , performs. plus characteristics of application under load instance type.

1) want pool size > expected simultaneous queries running on host.
2) never want situation number of clients * pool size approaches max connection limit.

remember though simultaneous queries less simultaneous web requests since code uses connection query , releases it.

so need model application understand actual queries (and amount) happen 75k users. lot less 75k/second db queries second.

you can construct script - used jmeter - , run test simulate performance. 1 of items did during our test increase pool higher , see difference in performance. used large number (100) after doing baseline , found number made difference. dropped down until start making difference. in our case 15 , set 20.

this against t2.micro our app server. if change servers bigger, value go up.

please note pay cost on application startup when set higher number...and incur overhead on server keep idle connections making larger need isn't good.

hope helps.


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