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Error in connector: Error creating a database connection. (Operation timed out (mobc timeout))

Freshabout 5 years ago
Mar 14, 20260 views
Confidence Score80%
80%

Problem

Bug description Sometimes, due to DB connections limit, the client fails with this error: [code block] my DB configuration is like so: `DATABASE_URL="mysql://someUser:somePass@host/db?connection_limit=10"` Note: `connection_limit` How to reproduce It happened to me when trying to create/update/delete several entities at the same time, for example: [code block] Expected behavior The client should be able to recover from a timeout connection. Environment & setup - OS: Ubuntu - Database: Mysql - Node.js version: 14 - Prisma version: 2.11.0

Error Output

Error in connector: Error creating a database connection. (Operation timed out (mobc timeout))

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1 Fix

Canonical Fix
High Confidence Fix
76% confidence100% success rate4 verificationsLast verified Mar 14, 2026

Solution: Error in connector: Error creating a database connection. (Operation timed out (mobc timeout))

Low Risk

I can reproduce this with a heroku database with connection limit of 10 and this simple script. All timed out calls doesn't recover. Connections in the heroku reaches max of 11 then it starts to give timeouts. Reproduction: https://github.com/harshit-test-org/prisma-issue-4280

76

Trust Score

4 verifications

100% success
  1. 1

    I can reproduce this with a heroku database with connection limit of 10 and this

    I can reproduce this with a heroku database with connection limit of 10 and this simple script.

  2. 2

    All timed out calls doesn't recover. Connections in the heroku reaches max of 11

    All timed out calls doesn't recover. Connections in the heroku reaches max of 11 then it starts to give timeouts.

  3. 3

    Reproduction: https://github.com/harshit-test-org/prisma-issue-4280

    Reproduction: https://github.com/harshit-test-org/prisma-issue-4280

Validation

Resolved in prisma/prisma GitHub issue #4280. Community reactions: 6 upvotes.

Verification Summary

Worked: 4
Partial: 1
Last verified Mar 14, 2026

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Environment

Submitted by

AC

Alex Chen

2450 rep

Tags

prismaormpostgresqlbug/2-confirmedkind/bug