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Tool Report: Velocitop Catapult

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Published July 2002

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  1. Getting Started
  2. Connection Manager
  3. Profiler
  4. Tuning Agent
  5. Load Manager
  6. Conclusion
  7. Obtaining a trial copy of Velocitop Catapult

Getting Started

Velocitop Catapult is a commercial-grade enterprise software product that addresses Java-to-Oracle performance tuning via the JDBC layer.

Using a methodology called "Roundtrip Optimization", performance

data is automatically gathered from applications with near-zero overhead. This

data is fed to the Catapult tuning server, which identifies slow queries, automatically

experiments with optimizations, takes user input and approvals through a web-based

administration tool, and then returns optimizations and load-control commands

back to the application. Velocitop also provides a suite of operational tools

to ensure consistent levels of performance and uptime.

Catapult is implemented via two components:

Installation of the Velocitop Catapult software is quick and does not require

any code changes or recompilation. To install the Tuning Server, you simply

download the code from the Velocitop website, run the startup script, and complete the web-based installation wizard.

To install the JDBC Wrapper file for the Oracle JDBC Driver, you would swap

the appropriate driver file included in the download (depending on whether you

are using the Oracle Thin Driver or OCI Driver) with your current Oracle JDBC

driver .jar / .zip. Finally, you would update the JDBC connection info to reference the Tuning Server.

Once the JDBC Wrapper and Tuning Server are installed, you can log into the

web-based console to complete the configuration process and begin viewing profile data and optimizations.

Catapult consists of the following four functional modules:

Connection ManagerCPU hotspots

Before roundtrip optimization can begin, the JDBC drivers must be properly

configured for speed. Oracle's user manual describing how to set up and configure

the Oracle JDBC drivers is so lengthy (700 pages!), that important performance

features, such as native connection pooling or prepared statement caching, are

often overlooked. Velocitop Catapult provides a detailed configuration wizard,

so you can get your system up and running quickly with the proper performance

configurations. Catapult also provides a tool to centrally manage and verify

connection settings, such as application logins, as well as restart database

connections without restarting applications. An additional benefit of the connection

management console is that all connection logins are always encrypted. This

closes a major security hole relating to storing database logins in clear-text files on application servers.

For the example used in this article, we have a Java application using the

Thin JDBC Driver. Using the Connection Manager, we disable Oracle Connection

Caching, enable Oracle Pooled Connections, and specify a maximum of ten simultaneous Tuning Server connections for optimization testing.


Heap walker - Classes

We then use the Profiler module which monitors and reports on all SQL queries

in order to gain visibility into SQL performance and exceptions over any specified

period of time. In this example, we are interested in seeing what has caused

a slowdown over the last hour. We use the Profiler's functionality to sort queries

by their performance impact based on various measurements such as total execution

time, time to "first row", and number of times called. We also then

filter the reports in a variety of ways - by database, by application machine, by thread, or by application - to further isolate the problematic SQL.

Catapult's unique JDBC-wrapper technology allows it to

gather a variety of detailed performance statistics, including Java stack-trace

information. We use this stack trace function to correlate SQL queries to the

Java functions that called them, and vice-versa. The Velocitop JDBC wrapper

is engineered to have a very low overhead (approximately 1% performance impact), making it suitable for both QA and production environments.

In our example, we find that the top-ranked SQL statement in terms of negative performance impact is

SELECT MIN(amount), ?

FROM Sales WHERE custID<?

This SQL statement has an Average Total Execution time

of 630 ms, and an Average First Row Execution Time of 550 ms which is ten times

greater than the second-ranked statement so it is an obvious culprit for the

system slowdown. We then open the Stacktrace Browser to see the breakdown of all Java functions that called this SQL (by distribution of calls):



Tuning AgentCPU hotspots

We now move on to the Tuning Agent, which collects the performance data from

the JDBC wrapper and then runs a variety of tests to identify optimization opportunities relevant to both SQL hints as well as data caching.

In our example, the Tuning Agent has tested nine query variations for the SQL

statement, and has found that the following revised statement represents the optimal alternative:

SELECT /*+ INDEX (Sales SALES_PRODUCT_INDEX) */ MIN(amount), ? FROM Sales WHERE custID<?

Catapult also generates a caching optimization related to this statement of

500 bytes, with a 20-second expiration timeframe. With these two optimizations

in place, we can already see a significant improvement in performance for our application.

Catapult will only run optimization tests when there is sufficient load, as

test results will not be accurate when run during off-peak hours. However, Catapult

is non-intrusive when running tests on a production system as it spreads tests

out over time and cuts off under-performing tests early, so as not to impact

the overall system performance. Additionally, Catapult continually compares

the tests to a control group, to make sure that any identified optimizations are statistically significant.

All optimizations can be approved before going live using the Catapult web-based

administration tool (or, Catapult can be defaulted to "auto-approve"

all optimizations). Once approved, optimizations are transmitted from the tuning

server back to the JDBC-wrapper. Most optimizations, load control commands,

and connection settings can be implemented transparently, without stopping and

starting application machines, another added benefit that improves overall system

uptime. Graphs then show performance before and after optimizations, for easy confirmation of performance improvements.

With manual performance tuning, optimizations are often left aside as the engineer

moves on to other more pressing tasks. Catapult, however, continually reviews

and re-tests optimizations, to make sure optimizations are still valid as your

system changes over time (e.g. Indexes added or dropped, larger or smaller data

sets, different mix of SQL queries, etc.). Also, since Catapult is an automated

software solution, it is able to consider all of your SQL queries, so it's a

valuable ally to engineers who are often too time-constrained to be able to

fine tune more than a small handful of queries.

Load ManagerCPU hotspots

In addition to specific query-level optimizations, Velocitop provides new

techniques to help manage overall query load. Velocitop monitors database performance

in real-time, and then can queue up queries if the overall performance suddenly

degrades (also known as 'throttling'). This can prevent a "total database

meltdown" scenario, where the database is so overloaded it has no chance

of recovering and must be restarted. This can often happen with hardware failures (e.g. a disk drive fails) or an unplanned spike in user traffic.

Another load management function is query prioritization. This works with throttling

to allow you to prioritize specific queries ahead of others. Prioritizations

can be defined in a variety of ways, including by Java function, SQL call, customer

ID, etc. During a slowdown, higher priority queries are executed before lower

priority queries, to ensure that your most important queries get through. This

helps to assign your system resources based on your business requirements (i.e. the most important customers get the best experience).

Catapult also provides query load balancing functionality. If you have multiple,

replicated databases in an Active-Active configuration, Catapult can load balance

your queries across these multiple databases. In the event that one database

experiences a slowdown, queries can be automatically re-routed to the fastest



Performance problems can quickly create major headaches

for operational managers and engineers, as they are expensive to resolve and

difficult to predict and, therefore, difficult to budget. Velocitop focuses

on the link between applications and databases, as this is a key area for performance

tuning and provides the best returns for the time and money spent. Velocitop

Catapult is a commercial-grade, fully automated solution for JDBC layer performance

tuning. It delivers database connection configuration and management, low-overhead performance profiling, automated tuning, and query load control.

Catapult delivers a compelling ROI by making employees more productive and

saving money on performance consulting services. Engineers are freed from having

to work on low-level tuning tasks and can quickly identify the source of problems

with detailed JDBC-level profiling information. Also, by improving overall system

performance and normalizing response time during spikes, Catapult enables managers to postpone expensive hardware and software upgrades.

Obtaining a trial copy of Velocitop


To get a 2-week evaluation copy of Velocitop Catapult, go

to the Trial page. Catapult requires

one machine to use as the Tuning Server running Solaris, Windows, or Linux, with

500Mb Disk and 200Mb RAM available. Catapult supports all J2EE/Oracle applications.

Last Updated: 2022-06-29
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