Extracting Query Block Information from Optimizer Trace
Programmatically extracting the query block information from the optimizer trace Continue Reading
Author: Nenad Noveljic
Scalar Subqueries with OUTER JOIN
Wrong cost calculation when an OUTER JOIN drives the execution of a correlated scalar subquery in SELECT DISTINCT Continue Reading
Join Predicate Push Down Additional Phase
Analyzing Join Predicate Push Down Additional Phase by using the optimizer trace Continue Reading
Join Permutations Heatmaps
Generating heatmaps for join permutations using Python Continue Reading
Comparing TSQL and PL/SQL Performance
Why Oracle outperforms SQL Server Continue Reading
Microsoft Azure SQL Server CPU Performance
Comparing the performance of different MS Azure virtual CPU core configurations. Continue Reading
SOS_SCHEDULER_YIELD waits during low CPU utilization
SQL Server OS scheduler unexpectedly throttles the load which decreases the throughput and increases the response time variability. Continue Reading
TDS Encryption Overhead
Are you aware of your TDS encryption overhead? It’s often negligible, but your mileage may vary depending on the cipher suite. Continue Reading
Correlated Subqueries in the SELECT Clause (2)
Examples where Oracle optimizer doesn’t unnest subqueries in the SELECT clause Continue Reading
Correlated Subqueries in the SELECT Clause
How Oracle and SQL Server optimize correlated subqueries in the SELECT clause with an example how to manually optimize such queries for Oracle. Continue Reading