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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: HADR_SYNC_COMMIT Wait TypeRelated pillar: High Availability Is It a Problem? It can be, and it depends on the safety level. Microsoft describes DBMIRROR_SEND as a sign that the communications layer is starting to become overloaded and affect mirroring throughput. On a…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: HADR_SYNC_COMMIT Wait TypeRelated pillar: High Availability Is It a Problem? No. It is an idle wait, commonly filtered as benign, and Get Wait Statistics filters it out by default. What It Means Microsoft’s definition: database mirroring waits for events to process.…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: HADR_SYNC_COMMIT Wait TypeRelated pillar: High Availability Is It a Problem? Rarely. It is not a known contention point. Get Wait Statistics does not filter it out, so if it ranks, you will see it. Because a mirror usually runs little else,…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? No. It is a one-off at startup; our SQL Server 2025 lab had a single wait of about a second. Get Wait Statistics does not filter it out, so if…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: CXPACKET and CXCONSUMER Wait TypesRelated pillar: Performance & Troubleshooting ⚡CXSYNC_PORT is parallel plan threads waiting to open, close or synchronise the exchange ports that pass rows between them. The documented example is a long sort that must finish before the port…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: CXPACKET and CXCONSUMER Wait TypesRelated pillar: Performance & Troubleshooting Is It a Problem? Read it the way you read CXPACKET: it shows parallel plans are running, which is often what you want. Do not just lower the server MAXDOP to make…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: CXPACKET and CXCONSUMER Wait TypesRelated pillar: Performance & Troubleshooting Is It a Problem? No. It is not a known contention point, and our SQL Server 2025 lab had about 200 waits totalling a quarter of a second in a day. Get…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: LCK_M_X, LCK_M_S, and LCK_M_U Wait TypesRelated pillar: Performance & Troubleshooting Is It a Problem? It can be, though nothing documents it. The name ties it to the commit table that Change Tracking keeps, so the setting where it is plausible is…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: CXPACKET and CXCONSUMER Wait TypesRelated pillar: Performance & Troubleshooting Is It a Problem? Some of it is a fixed cost at the start of every parallel columnstore build. It becomes worth attention when the first segment takes a long time, because…

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⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: RESOURCE_SEMAPHORERelated pillar: Performance & Troubleshooting ⚡CMEMTHREAD is a task waiting for a thread-safe memory object, because many tasks are allocating from the same one at once. Small amounts are normal. Sustained at the top of your waits, one memory object has…

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