⚠Caching won't work with replication enabled

[matiasmir]

Issue type:

[ ] question
[ x] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[x ] postgres
[ ] cockroachdb
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[x ] latest
[ ] @next
[ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem:
Hi everyone, I've configured typeorm with replication using two instances, a master(read-write) and a slave(read), so if my understading is correct all the select/get queries are executed in the slave instance and all the updates/set/insert/etc are executed in the master db but today I've enabled caching for my db and it doesn't work, it shows the following error when I try to get something from the db:

{ error: cannot execute INSERT in a read-only transaction at Connection.parseE (/app/node_modules/pg/lib/connection.js:604:13) at Connection.parseMessage (/app/node_modules/pg/lib/connection.js:403:19) at Socket.<anonymous> (/app/node_modules/pg/lib/connection.js:123:22) at Socket.emit (events.js:198:13) at Socket.EventEmitter.emit (domain.js:448:20) at addChunk (_stream_readable.js:287:12) at readableAddChunk (_stream_readable.js:268:11) at Socket.Readable.push (_stream_readable.js:223:10) at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17) name: 'error', length: 118, severity: 'ERROR', code: '25006', detail: undefined, hint: undefined, position: undefined, internalPosition: undefined, internalQuery: undefined, where: undefined, schema: undefined, table: undefined, column: undefined, dataType: undefined, constraint: undefined, file: 'utility.c', line: '246', routine: 'PreventCommandIfReadOnly' }

I suppose that this is being caused when a get request is received on my API and then typeorm selects the slave database in order to execute the query and then it tries to do a INSERT to chache the results using the slave instance and because it is READ ONLY it throws that error, so I guess that this is a bug, correct me if I'm wrong, thanks in advance!

[artemkonovalov-ss]

Same for MySQL. Cache is not working

That doesn't produce errors but it hits DB per each request, but not a cache

[madeindjs]

I created a dedicated repository to reproduce the error using Docker to mount a master/slave environment

git clone https://github.com/madeindjs/typeorm_bug
cd typeorm_bug
docker-compose up

This will produce the following error

QueryFailedError: cannot execute INSERT in a read-only transaction
    at new QueryFailedError (/usr/src/app/src/error/QueryFailedError.ts:9:9)
    at PostgresQueryRunner.<anonymous> (/usr/src/app/src/driver/postgres/PostgresQueryRunner.ts:228:19)
    at step (/usr/src/app/node_modules/tslib/tslib.js:143:27)
    at Object.throw (/usr/src/app/node_modules/tslib/tslib.js:124:57)
    at rejected (/usr/src/app/node_modules/tslib/tslib.js:115:69)
    at processTicksAndRejections (internal/process/task_queues.js:93:5) {
  length: 118,
  severity: 'ERROR',
  code: '25006',
  detail: undefined,
  hint: undefined,
  position: undefined,
  internalPosition: undefined,
  internalQuery: undefined,
  where: undefined,
  schema: undefined,
  table: undefined,
  column: undefined,
  dataType: undefined,
  constraint: undefined,
  file: 'utility.c',
  line: '246',
  routine: 'PreventCommandIfReadOnly',
  query: 'INSERT INTO "query-result-cache"("identifier", "query", "time", "duration", "result") VALUES (DEFAULT, $1, $2, $3, $4)',
  parameters: [
    'SELECT name FROM "user" "u" -- PARAMETERS: []',
    1622197257656,
    2000,
    '[{"name":" toto"},{"name":" toto"}]'
  ]
}