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AWS
Benchmarking
Oracle Cloud Infrastructure (OCI)
October 19, 2017

Oracle Cloud Infrastructure vs AWS. NVMe SSD test for MemSQL use case.

One of the big use cases for Oracle Cloud Infrastructure (OCI) formerly known as Baremetal Cloud is noSQL and newSQL. Oracle states what big advantage on storage layer would be PCIe based NVMe SSD with super low latency. And elimination of virtualization layer would let it shine at full. While MemSQL row store is in-memory, […]

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Datastax
Spark
October 16, 2017

Accessing Datastax Spark – Basic Examples

DSE 5.0.7, Spark 1.6.3 Accessing Spark Accessing spark from outside the spark cluster Spark SQL Pyspark Scala Spark Job Spark Thrift / Beeline note Difference between thrift query and spark-sql query, is that thrift server uses a shared SparkSQL context whereas Spark SQL does not. Accessing Cassandra Materialized Views from Spark users_by_email_mview is a materialized […]

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AWS
Datastax
NoSQL
October 7, 2017

Datastax Spark on AWS

Configuration: DSE 5.0.6 (See Datastax Cassandra on AWS for Installation Details) so when you start dse spark or dse spark-sql, in spark UI, you can see 3 out of 4 cores allocated Verification: Finding the spark master Spark Web UI: http://<node1>:7080Now in http://:4040/stages/, we can see 1 Fair Scheduler Pool, with schedule mode as FAIRFrom AWS […]

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Cloud
Oracle Cloud Infrastructure (OCI)
September 26, 2017

Install oracle bmcs (oraclebmc-cli)

Here is a quick example how to install Oracle Braremetal cloud cli on MacOS or Linux.Please note what oracle just renamed Braremetal cloud to Oracle Cloud Infrastructure (OCI) First thing first – python. I recommend to start with Python 3.6 or later. Oracle says python 2 is also supported, but when I tried bmcs installed […]

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AWS
NoSQL
September 24, 2017

Datastax Cassandra on AWS

Setting up AWS EC2 Instance Type: m4.xlarge, 4 node cluster, 2 in each AZStorage: Two EBS volumes, data volume 400GB, 150GB log volume, root volume 150GB (General Purpose SSD)OS:Amazon Linux AMI 2016.09.0 (HVM), SSD Volume Type – ami-b953f2daThe Amazon Linux AMI is an EBS-backed, AWS-supported image. The default image includes AWS command line tools, Python, Ruby, Perl, […]

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Database
Oracle
November 20, 2016

How to make partition elimination/pruning to work

If you have situation when partition elimination/pruning does not work, here are couple effective tricks to fix it. 1. If query derives partition key from sub-query, for example (query where sale_date is a partition key): Replace sub-query with DETERMINISTIC function: In most cases it should not be differences between sub-query and function. But there are […]

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Datastax
October 28, 2016

Cassandra Monitoring

Choice of Tool New Relic http://newrelic.com/plugins/3legs/113Monitor Cassandra statistics using the 3legs plugin. Metrics include Read and Write latency (global and per host), Cache statistics, Pending compactions, flushes and more. Datastax – OpsCenter http://www.datastax.com/documentation/opscenter/4.1/pdf/opscuserguide41.pdfDataStax OpsCenter is a visual management and monitoring solution for Apache Cassandra and DataStax Enterprise.The DataStax agents are installed on the Real-time (Cassandra), […]

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Tips & Tricks
October 24, 2016

Junos Pulse VPN client on Linux. Two phase auth. 64bit. How to make it all work.

There are several problem common problems with Juniper SSL VPN on support of Linux clients: 1.Most 64-bit platforms are not supported.2.Junos Pulse SSL VPN does not support Linux at all. Best way to cover problem “1” is:http://ubuntuforums.org/showthread.php?p=11189826#post11189826There is also well known mad-scientist way but its more complex. Problem “2” is a bit more involved. In […]

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Database
Oracle
October 25, 2014

ORA-01555 on standby

If you see “ORA-01555: snapshot too old” from Select what is been run on Physical standby, but same select runs on primary just fine, and all relevant init.ora parameters and undo tablespace are exactly identical between primary and standby,- its odd. But its easy to explain. First check if DB is below 11.2.0.3 DB it […]

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Performance Tuning
June 4, 2013

High CPU usage on DB host?

Its Unix 101 statement, but I have heard it wrong so many time, so decided to put a blog for it. If in OLTP environment, per ‘top’ %wa (IOWAIT) is major contributor for CPU busy, adding CPU would not help. There is no need for more CPU. Period. ************** %wa IS PERCENTAGE WHAT COUNT TO […]

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Oracle
Performance Tuning
June 3, 2012

Index Clustering factor. One way how to avoid negative performance impact on joins which involves bad clustered indexes.

High Index Clustering factor is popular problem in SQL world.The most known solution for it – rebuild table ordering by columns what are in the index.But in real world, with table size growing exponentially its not always practical or possible to do it. Here is one way to avoid index clustering problem by SQL optimization.. […]

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