how to avoid java.util.concurrent.ThreadPoolExecutor error with prisma - docker-compose

Question

I am currently using Prisma on a large scale project. When performing a complex query, the Prisma cluster often errors out with the following message in the docker-logs (I'm redacting the error for readability):
{"key":"error/unhandled","requestId":"local:ck7ditux500570716cl5f8x3r","clientId":"default$default","payload":{"exception":"java.util.concurrent.RejectedExecutionException: Task slick.basic.BasicBackend$DatabaseDef$$anon$3#552b85a4 rejected from slick.util.AsyncExecutor$$anon$1$$anon$2#1d4391f7[Running, pool size = 9, active threads = 9, queued tasks = 1000, completed tasks = 43440]","query":"query ($where: TaskWhereUniqueInput!)
{\n task(where: $where) {\n workflow {\n tasks {\n id\n state\n parentReq\n frozen\n parentTask {\n id\n state\n }\n }\n }\n }\n}\n","variables":
"{\"where\":{\"id\":\"ck6twx873bs550874ne867066\"}}",
"code":"0","stack_trace":"java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2063)\\n
java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:830)
...
"message":"Task slick.basic.BasicBackend$DatabaseDef$$anon$3#552b85a4 rejected from slick.util.AsyncExecutor$$anon$1$$anon$2#1d4391f7[Running, pool size = 9, active threads = 9, queued tasks = 1000, completed tasks = 43440]"}}
This is a frequent error when handling large queries. Has anyone come up with a way to configure Prisma or do internal batch operations to avoid this concurrency error?

Answer 1

Option 1:
I ran into this issue when running a prisma mutation in a loop with a lot of data which seemed to have created too many concurrent database operations.
My solution was to throttle the requests:
thingToLoop.map(() => {
await new Promise(resolve => setTimeout(resolve, 1000));
// Prisma operation here. Essentially this just makes the operation wait for one second between each operation.
})
Option 2
I've read other posts that say that you can set a limit to the number of concurrent connections as well.
See: https://v1.prisma.io/docs/1.25/prisma-server/database-connector-POSTGRES-jgfr/#overview
Essentially, this restricts the number of connections when too many are being created. See the following prisma config as an example:
PRISMA_CONFIG: |
managementApiSecret: __YOUR_MANAGEMENT_API_SECRET__
port: 4466
databases:
default:
connector: postgres
migrations: __ENABLE_DB_MIGRATIONS__
host: __YOUR_DATABASE_HOST__
port: __YOUR_DATABASE_PORT__
user: __YOUR_DATABASE_USER__
password: __YOUR_DATABASE_PASSWORD__
connectionLimit: __YOUR_CONNECTION_LIMIT__