I am considering using the TimesTen In-Memory Database for my application but I need high-availability. Can TimesTen provide this and if so how?
Yes, TimesTen has excellent high availability capabilities.
For TimesTen Classic you can configure high availability using TimesTen active/standby pair replication. Details here: https://docs.oracle.com/database/timesten-18.1/TTREP/toc.htm
For TimesTen Scaleout, high availability is automatic and is based on the configured K- factor for the database (>1 gives you HA). Details here: https://docs.oracle.com/database/timesten-18.1/TTGRD/overview.htm#TTGRD118
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Does Anybody have prior experience to set up Oracle Exadata Active-Active Cluster across OCI regions yet? If yes, can you share possible best practices and guiding principles if possible.
The goal is to set up an Active-Active Oracle Exadata cluster across two OCI regions, so customer can readily access other region if one region goes down. It has to be spontaneous without any downtime. It should not be read only Passive site and if required other site can be used (R & W mode ) at any given point. The requirement is, NOT to waste infra as Passive or Stand by, instead it is expected to use all infra as Active serving customers.
The goal is to set up an Active-Active Oracle Exadata cluster across two OCI regions, so customer can readily access both regions simultaneously at the same time. It has to be spontaneous without any downtime.
Usually, It is known that Dataguard and Goldengate can be used, but I am looking for specific implementation best practices and architectural principles considering App Middle tier accessing DB cluster spontaneously.
Your mentioned that "The goal is to set up an Active-Active Oracle Exadata cluster across two OCI regions, so customer can readily access other region if one region goes down. It has to be spontaneous without any downtime."
The terminology Active-Active or Active-Standby is used from database semantics rather than for an Exadata Cluster(DB System/VM Cluster). So i am going to take the question as that the goal here is to design a DR solution for Exadata database which has stringent RTO goals and you want a solution which is automatic/spontaneous without downtime .
Active Dataguard : OCI/DBAAS allows customers to configure a cross region dataguard . Dataguard(standby) databases are an exact (block to block) copy of the Primary database . Dataguard can be configured in Active dataguard mode which means that the standby database is opened in a Read Only mode . This essentially means that queries (Selects) could be offloaded to the standby database .
a. With proper planning and execution, Oracle Data Guard and Active Data Guard role transitions can effectively minimize downtime and ensure that the database environment is restored with minimal impact on the business.
b. A failover is used when the primary database is deemed lost or unrecoverable, or the expected time to repair exceeds the required recovery time objective (RTO). During a failover the primary database is taken offline at one site and a standby database is brought online as the primary database. Failover can be completely automated using Data Guard Fast-Start Failover or it can be a manual, administrator-driven process . Fast-Start Failover eliminates the uncertainty inherent in a process that requires manual intervention, assuming similar measures have been taken to automate the failover of the application tier to the new primary database. Fast-Start Failover automatically executes a database failover within seconds of an outage being detected and can complete in seconds.
Please note OCI/DBAAS has not implemented fast start failover yet meaning that this cannot be done via console or DBAAS API's .
Please take a look at https://www.doag.org/formes/pubfiles/5256791/2013-DB-Larry_Carpenter-Session_Keynote__Best_Practices_for_Data_Availability_and_Disaster_Protection-Praesentation.pdf (Page level 38 for more details on Fast start failover )
Goldengate
Using goldengate customers can configure Active-Active primary-standby wherein both primary and standby are open in Read write mode . Please note that goldengate replication differs from dataguard replication in the sense that Goldengate standby is not an exact block to block copy of the Primary . There could also be restrictions around specific object datatypes which goldengate can support .
For more details on configuring goldengate to maintain a live standby database and failover best practices , please refer to
https://docs.oracle.com/en/middleware/goldengate/core/19.1/admin/configuring-oracle-goldengate-maintain-live-standby-database.html#GUID-6CE0810E-A681-4CCA-9BC8-539E8A364FD3
https://www.oracle.com/technetwork/database/availability/8399-goldengate-dataguard-1888654.pdf
Please note there is no current offering yet for Goldengate in OCI/DBAAS meaning no console/DBAAS API's for configuring / setting up goldengate standby .
I am pretty new to Oracle Golden Gate, wanted to understand if it possible to create a bidirectional sync between Oracle 12x and Cassandra(DSE) using Oracle Golden Gate? Searched several places in internet but most examples are replicating data between Oracle databases. I started wondering if it is even possible to do so. Can anyone help me with any documentation?
There is a separate module called Oracle GoldenGate for BigData. It supports many NoSQL replication targets.
One of the supported BigData databases is also Apache Cassandra.
There is a separate manual explaining how to use it.
There is no separate module that allows you to connect Apache Cassandra as the source of your replication. If you need such replication you need to provide some intermediate step. The source of replication for Oracle GoldenGate can only be a database (Oracle, TimesTen, DB2, Informix, MySQL, MS SQL Server, NonStop SQL/MX, SAP/Sybase ASE, Teradata) or a JMS queue.
I am newer one on Oracle system. I am facing to a problem related Oracle database syncing.
We have 2 databases(A and B). Database A is synced to database B via Oracle GoldenGate. When too many records insert into database A, Oracle GoldenGate falls down.
Can you please suggest another solution for this issue ? We interest in physical hardware solutions if it is available.
Thank you.
Golden Gate is used for logical replication. Hardware replication is a physical kind of replication, like Oracle Data Guard. There will be a reason for the choice for logical replication. If not, go for Oracle Data Guard, which is very efficient and robust.
I have a requirement to ingest the data from an Oracle database to Hadoop in real-time.
What's the best way to achieve this on Hadoop?
The important problem here is getting the data out of the Oracle DB in real time. This is usually called Change Data Capture, or CDC. The complete solution depends on how you do this part.
Other things that matter for this answer are:
What is the target for the data and what are you going to do with it?
just store plain HDFS files and access for adhoc queries with something like Impala?
store in HBase for use in other apps?
use in a CEP solution like Storm?
...
What tools is your team familiar with
Do you prefer the DIY approach, gluing together existing open-source tools and writing code for the missing parts?
or do you prefer a Data integration tool like Informatica?
Coming back to CDC, there are three different approaches to it:
Easy: if you don't need true real-time and have a way to identify new data with an SQL query that executes fast enough for the required data latency. Then you can run this query over and over and ingest its results (the exact method depends on the target, the size of each chunk, and the preferred tools)
Complicated: Roll your own CDC solution: download the database logs, parse them into series of inserts/updates/deletes, ingest these to Hadoop.
Expensive: buy a CDC solution, that does this for you (like GoldenGate or Attunity)
Expanding a bit on what #Nickolay mentioned, there are a few options, but the best would be too opinion based to state.
Tungsten (open source)
Tungsten Replicator is an open source replication engine supporting a variety of different extractor and applier modules. Data can be extracted from MySQL, Oracle and Amazon RDS, and applied to transactional stores, including MySQL, Oracle, and Amazon RDS; NoSQL stores such as MongoDB, and datawarehouse stores such as Vertica, Hadoop, and Amazon rDS.
Oracle GoldenGate
Oracle GoldenGate is a comprehensive software package for real-time data integration and replication in heterogeneous IT environments. The product set enables high availability solutions, real-time data integration, transactional change data capture, data replication, transformations, and verification between operational and analytical enterprise systems. It provides a handler for HDFS.
Dell Shareplex
SharePlex™ Connector for Hadoop® loads and continuously replicates changes from an Oracle® database to a Hadoop® cluster. This gives you all the benefits of maintaining a real-time or near real-time copy of source tables
Apache Sqoop is a data transfer tool to transfer bulk data from any RDBMS with JDBC connectivity(supports Oracle also) to hadoop HDFS.
What are the available hadoop remote data sources connectivity options?
I know about drivers for MongoDB, MySQL and Vertica connectivity but my question is what are other available data sources that have driver for hadoop connectivity?
These are the few I am aware of :
Oracle
ArcGIS Geodatabase
Teradata
Microsoft SQL Server 2008 R2 Parallel Data Warehouse (PDW)
PostgreSQL
IBM InfoSphere warehouse
Couchbase
Netezza
Tresata
But I am still wondering about the intent of this question. Every data source fits into a particular use case. Like, Couchbase for document data storage, Tresata for financial data storage and so on. Are you going to decide your store based on the connector availability??I don't think so.
Your list will be too long to be useful.
Just one reference: cascading gives you access to almost anything you want to access. More, you're not limited with Java. For example there is scalding component which provides very good framework for Scala programmers.