Bypassed Subquery Unnesting for Anti Join
Columns instead of constants in the SELECT clause of a NOT EXISTS subquery can lead to bad execution plans. Continue Reading
Oracle
Anti Join with Range Predicate
Performance issue in the Avaloq backend/frontend interface Continue Reading
Why Replacing an OJDBC Driver in Oracle Cloud Control Installation is a Bad Idea?
A custom OJDBC driver can break patching Continue Reading
TNS-12599: TNS:cryptographic checksum mismatch
Older JDBC versions causing TNS-12599: TNS:cryptographic checksum mismatch Continue Reading
Three Ways to Suspend an Oracle Process
While analyzing complex problems and researching internals in Oracle database, I’ve often had to observe process interaction in slow motion. This requires temporarily suspending a process until another process finishes a relevant chunk of work, and then resume the suspended… Continue Reading
fbar timer – Active Session History Instrumentation Gap
Unaccounted database time in ASH caused by fbar timer wait event. Continue Reading
Troubleshooting an emcli Login Problem
A hidden dependency in emcli Continue Reading
Tracing Library Cache Locks 3: Object Names
A fully-fledged gdb script for tracing library cache locks Continue Reading
Tracing Library Cache Locks 2: Using Debugger
Library cache lock allocations aren’t instrumented in Oracle database, but we can extract this information with debugger. Continue Reading
Performance Problem with Incremental Statistics Calculation
A frequently executed SQL causes problems with the initial incremental statistics calculation. Continue Reading