Upgrades And Regressions

Kendra Little explains when upgrades can cause performance to suffer:

The cluster’s servers and SQL Server configurations were built to be as close to identical as possible to the previous instance (memory, cores, disk, maxdop, CTP, etc).

After the migration, I noticed that CPU utilization jumped from the normal 25% to a consistent 75%.

I did several other migrations with similar server loads with no issues, so I’m a bit puzzled as to what might be going on here. Could the upgrade from SQL Server 2008 R2 to SQL Server 2012 simply be exposing bad queries that 2008 was handling differently?

Kendra goes through a number of reasons, building a troubleshooting guide in the process.  This is a great read.

Related Posts

Row-By-Row Is Slow-By-Slow

Lukas Eder points out that row-by-row updates are a great way of slowing down your system: The best way to find out is to benchmark. I’m doing two benchmarks for this: One that is run in PL/SQL, showing the performance difference between different approaches that are available to PL/SQL (namely looping, the FORALL syntax, and a single […]

Read More

Reading SQL Server Error Logs

Jana Sattainathan has a procedure which makes it easier to read the error logs in SQL Server: xp_ReadErrorLog has some limitations Reads only the specified error log whose ArchiveNumber is specified Shows only the rows with matching string (not adjacent context info rows) The first bullet is obvious in that we cannot read ALL the […]

Read More

Categories

July 2016
MTWTFSS
« Jun Aug »
 123
45678910
11121314151617
18192021222324
25262728293031