Tag Archives: ash

Presentation “Real-Time SQL Tuning” at Hotsos Sym2014 and UTOUG TD2014

This presentation was delivered at the Hotsos Symposium 2014 and at the Utah Oracle Users Group (UTOUG) Training Days 2014.

It describes a PL/SQL package that I put together called “ash_xplan.sql” which can be used to display real-time information about a SQL statement currently executing.  This package combines information from the Active Session History (V$ACTIVE_SESSION_HISTORY) or “ASH” view with information from the DBMS_XPLAN package.

As of Oracle12c v12.1, nothing in Oracle displays elapsed time while the SQL statement is still executing, not even SQL Monitor.

The source code for the “ash_xplan.sql” script is on the Scripts page of this website, along with sample spooled output.

Presentation “RDBMS Forensics – Troubleshooting Using ASH”

Arthur C. Clarke wrote that any sufficiently advanced technology is indistinguishable from magic, and it sometimes makes troubleshooting seem like magic, or perhaps art. But it is neither magic nor art; it is process and this presentation uses a case study, such as resolving the ORA-03136 “connection lost” error, to demonstrate that process and to show how components such as ASH, typically thought of as performance tuning tools for DBAs, are also useful diagnostic tools for everyone, particularly developers.  Attendees will learn a forensic, empirical approach to troubleshooting and see a demonstration of a complex troubleshooting task resulting in a non-intuitive but empirically sound resolution.  This presentation should make you think of Active Session History as something like queryable trace information captured and stored within the database.

This is the presentation slidedeck to accompany the white paper of the same title.

Paper “RDBMS Forensics – Troubleshooting Using ASH”

Arthur C. Clarke wrote that any sufficiently advanced technology is indistinguishable from magic, and it sometimes makes troubleshooting seem like magic, or perhaps art. But it is neither magic nor art; it is process and this presentation uses a case study, such as resolving the ORA-03136 “connection lost” error, to demonstrate that process and to show how components such as ASH, typically thought of as performance tuning tools for DBAs, are also useful diagnostic tools for everyone, particularly developers.  Readers will learn a forensic, empirical approach to troubleshooting and see a demonstration of a complex troubleshooting task resulting in a non-intuitive but empirically sound resolution.  This presentation should make you think of Active Session History as something like queryable trace information captured and stored within the database.

This is the white paper to accompany the presentation slidedeck of the same title.