Delete qualified rows from multiple tables with as few logical reads as you can. This puzzle gives a setup script for three small tables, the two rules for the delete and a starting script that costs 19 logical reads. Your task is to beat that number and stay correct.
DBCC DROPCLEANBUFFERS Impact on Memory: See a Cold Cache in Action
DBCC DROPCLEANBUFFERS removes every clean page from memory, so the next query reads from disk. This post counts the pages of one database before and after, shows why a CHECKPOINT comes first, and compares a cold read with a warm read.
SQL SERVER – What is Wait Type Parallel Backup Queue?
Only official documentation which I could find was about wait statistics related to Parallel Backup Queue is very little available online.
What is Source_Database_ID in Sys.Databases?- Interview Question of the Week #232
Question: What is Source_Database_ID in Sys.Databases and why it is mostly NULL? Very interesting question, I received indeed.
sysxmitqueue in msdb: Why It Grows and How to Clear It
Sysxmitqueue in msdb fills up when Service Broker messages cannot leave the server. A tested demo in its own database shows the pile, the reason, a one conversation cleanup and the NEW_BROKER reset. The msdb steps follow the same order.
SQL SERVER – DBCC CLONEDATABASE Error: Cannot Insert Duplicate Key Row In Object ‘sys.sysschobjs’ With Unique Index ‘clst’.
Learn how to fix: Cannot insert a duplicate key row in object ‘sys.sysschobjs’ with unique index ‘clst’ while using DBCC CLONEDATABASE.
CHECKPOINT Impact on Memory: Watch Dirty Pages Go to Zero
CHECKPOINT impact on memory is easy to measure. This post counts the dirty and clean pages of one database before and after a checkpoint. Dirty pages drop to zero, the clean pages grow by the same amount, and nothing leaves memory.