Category: Wait Types

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related pillar: Storage & Capacity PAGEIOLATCH_EX is the exclusive (write) variant of the page I/O latch wait. Where PAGEIOLATCH_SH means SQL Server is waiting to read a page from disk into the buffer pool, PAGEIOLATCH_EX means SQL Server is waiting to write a dirty…

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related pillar: Performance & Troubleshooting ⚡An LCK_M_* wait is a session stuck behind a lock another session holds, and one open transaction is usually behind the whole pile-up. Find the head of the blocking chain before you kill anything: Step 1 shows how. The…

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related pillar: Storage & Capacity IO_COMPLETION covers I/O waits that happen outside the normal buffer pool page path. Where PAGEIOLATCH_SH and PAGEIOLATCH_EX track data page reads and writes through the buffer pool, IO_COMPLETION tracks everything else: sort spills to tempdb worktables, backup file writes,…

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related pillar: High Availability HADR_SYNC_COMMIT appears exclusively on Always On Availability Group primary replicas configured with at least one synchronous commit secondary. With synchronous commit, the primary cannot acknowledge a transaction commit to the application until the log records for that transaction have been…

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related pillar: Performance & Troubleshooting CXPACKET and CXCONSUMER appear whenever SQL Server runs a query in parallel. They are coordination overhead between worker threads, not waits on a resource. ℹ️On SQL Server 2019 and later there are five of these waits, and CXPACKET is…