Warning: log write elapsed time
Oracle database internals – (redo) “log write elapsed time” instrumentation Continue Reading
Oracle
Automating Multi-Tenant Container Database Creation
There are two ways of creating multi-tenant container databases (CDB): Database Configuration Assistant and scripts. With the latter you have to run the script catcdb.sql for building data dictionary. This script calls a cascade of other Perl and sqlplus scripts,… Continue Reading
Enriching Trace with Call Stacks Part 2: gdb
How to use gdb for capturing call stacks when trace lines are written Continue Reading
WRH$_SYSMETRIC_HISTORY_INDEX UNUSABLE After 18c Upgrade
The index WRH$_SYSMETRIC_HISTORY_INDEX became UNUSABLE a couple of days after the Oracle 18c upgrade Continue Reading
Old-Style (non-cost-based) Join Predicate Push-Down Transformation Part 2 (Recursive WITH)
Wrong cost calculation with recursive WITH subquery and OJPPD Continue Reading
Bad commit Performance due to Slow Control File Writes
Analyzing slow commits with ash_wait_chains.sql, gdb and DTrace Continue Reading
Cost Propagation Errors
Reporting optimizer mistakes where the cost of operations in the execution plan wasn’t propagated to their parents Continue Reading
Old-style (non-cost-based) Join Predicate Push-Down Transformation
Suboptimal execution plans after falling back to OJPPD with hierarchical subqueries Continue Reading
Tracking Arguments with gdb
Tracking function arguments with gdb, with an example of tracing memory allocations in Oracle database Continue Reading
IO Sort Cost Calculation (2)
Interpreting formulae; comparison to full table scan calculation Continue Reading