I have a system of many node scripts that read and/or write automatically on a Postgres database all the time. One of those scripts randomly gets a deadlock. I would like to debug this, but the problem is that I don't know which other query cause the deadlock. (I use pg)

So my question is:

If I catch an error like this

{ error: deadlock detected
at Connection.parseE (/data/jenkins/workspace/03-10-Lotti-watcher-lotti-mod/import/node_modules/pg/lib/connection.js:604:13)
at Connection.parseMessage (/data/jenkins/workspace/03-10-Lotti-watcher-lotti-mod/import/node_modules/pg/lib/connection.js:403:19)
at Socket.<anonymous> (/data/jenkins/workspace/03-10-Lotti-watcher-lotti-mod/import/node_modules/pg/lib/connection.js:123:22)
at Socket.emit (events.js:197:13)
at addChunk (_stream_readable.js:288:12)
at readableAddChunk (_stream_readable.js:269:11)
at Socket.Readable.push (_stream_readable.js:224:10)
at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:150:17)
  name: 'error',
  length: 336,
  severity: 'ERROR',
  code: '40P01',
   'Process 2376 waits for ShareLock on transaction 55837412; blocked by process 22585.\nProcess 22585 waits for ShareLock on transaction 55837411; blocked by process 2376.',
  hint: 'See server log for query details.',
  position: undefined,
  internalPosition: undefined,
  internalQuery: undefined,
  where: 'while locking tuple (226684,50) in relation "lotti"',
  schema: undefined,
  table: undefined,
  column: undefined,
  dataType: undefined,
  constraint: undefined,
  file: 'deadlock.c',
  line: '1146',
  routine: 'DeadLockReport' }

can I get the query and/or user of the other process in order to isolate and identify the problem? Or anything like this, if it makes sense.

1 Answer 1


Sure. Just look into the PostgreSQL log file.

This information is not sent to the client for security reasons: otherwise, you could craft SQL statements that deadlock with other queries to see somebody else's statements, which might contain confidential data.

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