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Cassandra for Oracle DBA’s Part 4 – Data Distribution across Nodes

Shared Disk architecture in RAC where the data is shared across the nodes and at any point of time , every instance will give the same data using cache fusion.

But in Cassandra, the important part is storage is not shared storage, instead its sharded means partitioned and stored in each node.

And when […]

Cassandra for Oracle DBA’s Part 3 – Architecture

In Oracle (infact for any RDBMS) , will have a memory structures and processes (or thread) to process the data.

If we take Oracle as an example, lets look the similarities

1. Memory Architecture

Oracle Cassandra (NO-SQL DB) Parameter to Set in Cassandra.yaml file Comments SGA Java Heap Memory

cassandraenv.sh

MAX_HEAP_SIZE

SGA is […]

Cassandra for Oracle DBA’s Part 2 – Three things you need to know

Cassandra has three important differences if compared with RDBMS,

NO-SQL Data Stored as Columnar Structure Distributed Systems with Nothing Shared Architecture

Cassandra is combination of the Distributed Processing Systems (for high availability and scalability) with NO-SQL (to process unstructured data & schema less structure) & with Column Store(to store wide variety and velocity of data), […]

Cassandra for Oracle DBA’s Part 6 – Installing Cassandra

Installing Cassandra is straight forward, With CCM, is a tool to simulate a Cassandra cluster in a single host, Ideal for test environments or you want to make your hands on in Cassandra.

Further to install Cassandra in production size, you can directly download the Cassandra from Apache.org or Datastax for an enterprise version.

[…]

Cassandra for Oracle DBA’s – Part 1 : Nomenclature or Commands or Features Comparision

Although, there are heaps of fundamental changes between Oracle & Cassandra,

Just for fun, or for nomenclature or for commands or similar features are listed here , which may provide handy information to Oracle DBA’s

Oracle Keyword Cassandra Feature / Nomenclature SGA Java Heap Memory Buffer Cache Memtables LRU List Parition Index Summary Cache […]

Disabling Active Dataguard Feature

As we all know Active Dataguard is a licensed feature and whilst there is no parameter to control, indeed if just in case if you do not have a license and by chance your DBA has opened the standby database in readonly and started MRP then you are in troubles as it activates the Active […]

Database Migration & Upgrade 11g to 12c, Non ASM to ASM, Non RAC to RAC

Consider a Typical Database Migration which contains all of this below (and if down time is not a problem)

1. Into a new Database Host (NEW SERVER)

2. Convert to Non-ASM to ASM

3. Convert to Single Instance to RAC,

4. Upgrade to Database to 12c

Environment Details

Source Target DB Version: […]

Performance Troubleshooting Series : Identifying or Estimating How much PGA needed by Session/Query

Have got a question from one of fellow DBA that how much PGA the session will use or needed.

Well to answer this, first we need to know what PGA looks like and what it used for?

The follow shows the components of a PGA, the little space used for Stack, Env Variables and Private […]

Performance Troubleshooting Series: Query Parsing & Execution Times

As we all know, optimizer parse the statement to provide a plan, but to provide that Oracle Optimizer has to go through different phases called Parse, Execute, Fetch.

1. Parsing has three phases again,

Compiler: Compiles the statement to oracle readable format or oracle understandable state.

Estimator: Look out the […]

Configuring RAC on Amazon Cloud

Hello All,

This post is specifically for those who works on Amazon Cloud and want to build a RAC on Amazon EC2 Instances (machines).

There is a very good article in the AWS Documentation Articles (here), but the linux instances taken and built were very large and per hour it cost around 4$ each […]