While at Delphix, we did a lot of storage benchmarking. The I/O response times of Delphix depends, as one would logically imagine, heavily on the underlying disks. Sure Delphix can cache a lot ( with 1 TB of ram and 3x compression that’s 3TB and that 3TB can be shared by 10 or a 100 copies being the equivalent to 30TB or 300TB of databases) but really there will always be important I/O coming (more...)
photo by Thomas Hawk
Usage: pgmon.sh [username] [password] [host] <sid=postgres> <port=5432> <runtime=3600>
$ ./pgmon.sh kyle kyle mymachine.com
psql -t -h mymachine.com -p 5432 -U kyle postgres < /tmp/MONITOR/tmp/mymachine.com:postgres_collect.pipe &
Connected, starting collect at Wed Mar 8 12:05:12 PST 2017
starting stats collecting
AAS| blks_hit | blks_read | tup_returned | tup_fetched | tup_inserted | tup_updated | tup_deleted
pgload.jmx is JMX file you can load into Jmeter and run a substantial load on a Postgres database. Should work just as well on Oracle if you change the test SQL from “Select 1″ to “select 1 from dual”
Install jmeter on our machine . On my mac, I did
You will need the Postgres driver. I used
So Jmeter seems super cool.
I’ve only used it a little bit but it does seem a bit touchy about somethings (like spaces in input fields) and the errors are often less than obvious and I’m not finding that much out there on google for the errors.
Today I ran into the error
Variable Name must not be null in JDBC Request
and Googling it didn’t turn up anything.
I’m pretty sure I ran (more...)
This blog post is just a start at documenting some of my experiences with jmeter. As far as load testing tools go, jmeter looks the most promising to me. It has an active community, supports many different databases and looks quite flexible as far as architecting different work loads goes.
The flexibility of jmeter also makes it hard to use. One can use jmeter for many other things besides databases so the initial set up (more...)
Dan Tow, in his book SQL Tuning, lays out a simple method of tuning SQL queries. The method is
- Draw a diagram of each table in the query with Children above Parents
- Draw join lines between each join (many-to-many, one-to-many)
- Mark each table with a predicate filter and calculate the amount of table filtered out
Then to find a great optimal optimization path candidate
- Start at the table with the strongest predicate filter (the (more...)
Upgrading is always stressful – be it a computer, an Oracle database or an iPhone. There’s always a good chance for lost data and lost time dealing with complications.
So yesterday I picked up a new iPhone 7 from Verizon. The pickup was seamless. I had signed up for an upgrade program when I got the iPhone 6, so now I just walked in, gave them my old iPhone 6 and they gave me an (more...)
Every so often a DSS query that usually takes 10 minutes ends up taking over an hour. (or one that takes an hour never seems to finish)
Why would this happen?
When investigating the DSS query, perhaps with wait event tracing, one finds that the query which is doing full table scans and should be doing large multi-block reads and waiting for “db file scattered read” is instead waiting for single block reads, ie (more...)
Excited to see the announcement of Amazon RDS Performance Insight feature for database performance monitoring and tuning.
Having met the team for this project I can say from my personal view point that the importance and future success of this feature is clear as day to me. The team is awesomely sharp, the architecture is super impressive, and this is by far the most exciting performance monitoring and feedback system I’ve been involved with, surpassing the (more...)