How to fix P2027: Multiple errors occurred on the database during query execution in Prisma

import { Prisma } from '@prisma/client';

try {
  await prisma.user.create({
    data: {
      name: 'Alice',
      posts: {
        create: [{ title: 'First Post' }]
      }
    }
  });
} catch (error) {
  if (error instanceof Prisma.PrismaClientKnownRequestError) {
    if (error.code === 'P2027') {
      console.log('P2027 Error occurred');
      console.log('Error message:', error.message);
      console.log('Meta:', error.meta);
      // Look for the specific errors in the message
    }
  }
}

DATABASE_URL="mongodb+srv://username:[email protected]/mydb?retryWrites=true&w=majority"

sudo systemctl stop mongod

replication:
  replSetName: "rs0"

sudo systemctl start mongod

mongosh --eval "rs.initiate()"

DATABASE_URL="mongodb://localhost:27017/mydb?replicaSet=rs0"

docker run -d -p 27017:27017 --name mongodb \
  mongo:7 --replSet rs0

docker exec mongodb mongosh --eval "rs.initiate()"

DATABASE_URL="mongodb://localhost:27017/mydb?replicaSet=rs0&directConnection=true"

model User {
  id      String    @id @default(cuid())
  tags    String[]  // This doesn't handle NULL values in the array
}

UPDATE "User"
SET tags = ARRAY_REMOVE(tags, NULL)
WHERE tags IS NOT NULL;

model User {
  id      String    @id @default(cuid())
  tags    Json      @default("[]")
}

// Filter out nulls in application code
const cleanTags = user.tags.filter((tag): tag is string => tag !== null);

model Event {
  id        String   @id @default(cuid())
  duration  String   // Instead of Interval, store as string
}

model Event {
  id        String                        @id @default(cuid())
  duration  Unsupported("interval")?
}

async function retryOnP2027<T>(
  operation: () => Promise<T>,
  maxRetries: number = 3,
  delay: number = 100
): Promise<T> {
  let lastError: any;

  for (let attempt = 0; attempt < maxRetries; attempt++) {
    try {
      return await operation();
    } catch (error) {
      if (error instanceof Prisma.PrismaClientKnownRequestError) {
        if (error.code === 'P2027' && error.message.includes('conflict')) {
          lastError = error;
          // Exponential backoff
          await new Promise(resolve =>
            setTimeout(resolve, delay * Math.pow(2, attempt))
          );
          continue;
        }
      }
      throw error;
    }
  }

  throw lastError;
}

// Usage
const result = await retryOnP2027(async () => {
  return await prisma.$transaction([
    prisma.account.update({
      where: { id: 1 },
      data: { balance: { increment: 100 } }
    }),
    prisma.account.update({
      where: { id: 2 },
      data: { balance: { decrement: 100 } }
    })
  ]);
});

model Account {
  id      String  @id @default(cuid())
  balance Int
  version Int     @default(0)
}

const account = await prisma.account.findUnique({ where: { id: '1' } });
if (!account) throw new Error('Account not found');

await prisma.account.update({
  where: {
    id: account.id,
    version: account.version // Only update if version matches
  },
  data: {
    balance: account.balance + 100,
    version: { increment: 1 }
  }
});

# Include replica set name
DATABASE_URL="mongodb://localhost:27017/mydb?replicaSet=rs0"

# For MongoDB Atlas, use proper parameters
DATABASE_URL="mongodb+srv://user:[email protected]/mydb?retryWrites=true&w=majority"

# For local single-node replica set, add directConnection
DATABASE_URL="mongodb://localhost:27017/mydb?replicaSet=rs0&directConnection=true"

DATABASE_URL="postgresql://user:pass@localhost:5432/mydb?schema=public"

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function testConnection() {
  try {
    await prisma.$connect();
    console.log('Database connection successful');
    await prisma.$disconnect();
  } catch (error) {
    console.error('Database connection failed:', error);
  }
}

testConnection();

# Pull current database schema
npx prisma db pull

# Compare with your schema.prisma
# Look for differences in data types or constraints

// Problematic - may trigger P2027 on MongoDB without replica set
const user = await prisma.user.create({
  data: {
    name: 'Alice',
    posts: {
      create: [
        { title: 'Post 1' },
        { title: 'Post 2' }
      ]
    }
  }
});

// Safer approach
const user = await prisma.user.create({
  data: { name: 'Alice' }
});

const posts = await prisma.post.createMany({
  data: [
    { title: 'Post 1', authorId: user.id },
    { title: 'Post 2', authorId: user.id }
  ]
});

const result = await prisma.$transaction(async (tx) => {
  const user = await tx.user.create({
    data: { name: 'Alice' }
  });

  const posts = await tx.post.createMany({
    data: [
      { title: 'Post 1', authorId: user.id },
      { title: 'Post 2', authorId: user.id }
    ]
  });

  return { user, posts };
});