There are a lot of logs as CREATE TABLE IF NOT EXISTS "_SCHEMA"

[JeffGuKang]

New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest version of Parse Server.

Issue Description

There are a lot of log as CREATE TABLE IF NOT EXISTS "_SCHEMA" ( "className" varChar(120), "schema" jsonb, "isParseClass" bool, PRIMARY KEY ("className") )

And My DB connection pool is higher at the time.

I am not sure it makes some problem to the DB
or
the logs are made a lot when DB connection has a problem.

statement: CREATE TABLE IF NOT EXISTS "_SCHEMA" ( "className" varChar(120), "schema" jsonb, "isParseClass" bool, PRIMARY KEY ("className") )

I found some related query in PostgreAdopter:

parse-server/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js

Lines 875 to 892 in bbae55d

	async _ensureSchemaCollectionExists(conn: any) {
	conn = conn || this._client;
	await conn
	.none(
	'CREATE TABLE IF NOT EXISTS "_SCHEMA" ( "className" varChar(120), "schema" jsonb, "isParseClass" bool, PRIMARY KEY ("className") )'
	)
	.catch(error => {
	if (
	error.code === PostgresDuplicateRelationError ||
	error.code === PostgresUniqueIndexViolationError ||
	error.code === PostgresDuplicateObjectError
	) {
	// Table already exists, must have been created by a different request. Ignore error.
	} else {
	throw error;
	}
	});
	}

Steps to reproduce

1. Checking postgreSQL logs on the RDS.

2. The log is shown around every 30 secs

3. But sometimes there are too many logs when backend server requests a lot.

Actual Outcome

Expected Outcome

Environment

This is my Parse config.

const parseConfig = {
  cloud: __dirname + '/src/cloud/', // location after tsc
  appId: process.env.APP_ID,
  masterKey: process.env.MASTER_KEY,
  fileKey: process.env.FILE_KEY,
  serverURL: 'http://localhost:1337/parse', 
  auth: {
    kakao: kakaoAuthAdapter,
    apple: {
      client_id: process.env.APPLE_SIGNIN_CLIENT_ID, // optional (for extra validation), use the Service ID from Apple.
    },
  },
  maxUploadSize: '5mb',
  logLevel: process.env.NODE_ENV !== 'development' ? 'warn' : undefined,
  schemaCacheTTL: 1000 * 60 * 60 * 24 * 15, // 15 days
  cacheTTL: 1000 * 60 * 60 * 24 * 15, // 15 days
  allowClientClassCreation: false,
  enableSingleSchemaCache: true,
  enableExpressErrorHandler: false,
}

  const redisOptions = {url: 'redis://' + process.env.REDIS_CACHE_URL}
  const redisCache = new RedisCacheAdapter(redisOptions)

  parseConfig.cacheAdapter = redisCache

Server

• Parse Server version: 4.4.0
• Operating system: FILL_THIS_OUT
• Local or remote host : AWS scalable server (EC2)

Database

• System (MongoDB or Postgres): Postgres
• Database version: 11+
• Local or remote host: AWS Aurora postgres

Client

• SDK (iOS, Android, JavaScript, PHP, Unity, etc): iOS, Android
• SDK version: FILL_THIS_OUT

Logs

[mtrezza]

Thanks for reporting.

This may be related to #6193 and #6743.

Can you be more specific about what causes the calls to _ensureSchemaCollectionExists? In the source code there are some references that call this method, so depending on the operations you perform, these calls may be expected.

[JeffGuKang]

Postgre RDS <-------------> multiple EC2 instances
                      <--> Redis  <->

And it was caused when traffic increased. I will check the logs what is calling _ensureSchemaCollectionExists.

[dplewis]

_ensureSchemaCollectionExists Is called for every request to Postgres for some reason. I’m working on schema improvements right now. I can look into this

[mtrezza]

Seems related to #6743 and #6636.