SQL Server Error 1222: Lock Request Timeout — Who Holds the Lock?

Distinction between Error 1222, 1205 deadlock, and client timeouts, identifying the head blocker session, and RCSI implementation.

Reviewed by:Senior Database Architect & SRE (dataiotech Labs)

Tested Versions: SQL Server 2017 / 2019 / 2022

First 60 Seconds Emergency Protocol:

The error string is a symptom, not the root cause. Do not restart the server blindly. Run the diagnostic queries below to pinpoint the actual failure mode.

▸Symptoms

plaintext

Error 1222: Lock request time out period exceeded.

▸Triage Sequence

1Find Head Blocker:

sql

   SELECT r.session_id, r.blocking_session_id, r.wait_time/1000 AS wait_sec, t.text
   FROM sys.dm_exec_requests r
   OUTER APPLY sys.dm_exec_sql_text(r.sql_handle) t
   WHERE r.blocking_session_id <> 0;

1Inspect Sleeping Transactions:

A session with status = 'sleeping' and open_transaction_count > 0 indicates an uncommitted transaction leak.

1Enable Read Committed Snapshot Isolation (RCSI):

sql

ALTER DATABASE app_db SET READ_COMMITTED_SNAPSHOT ON;

Eliminates reader/writer blocking without the dirty reads caused by WITH (NOLOCK).

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