Given following two identical tables, on which run the same SQL, replicated in memory with oracle in-memory option - one table created out of the other.
each tables covers 24m rows.
Same structure ...
Now after some research - I detected one simple rule for provoking In-Memory scans :
Now finally after a long period of waiting - and looking presentations and reading blogs I was able to do In-Memory databasing on my own. Having sampled some theoretical background how a a pure In-Memory Db works with SAP HANA; my expectations on the Oracle In-Memory Option were high. Also because Oracle promised it would work without code change, out of the box.
The Oracle database is located on Sun Solaris Machine (more...)
Introduced as an Option Oracles In-Memory option will change the world of databasing also like SAP HANA does; Since July the release is out but the search for resources and documentation is poor;
Here some useful links I found.
Concepts (found a small passage) ...
just started the list - wiil enhance it - from time to (more...)
About 3 years ago SAP started to create a new database engine, SAP HANA, with a pure In-Memory concept. SAP aggressively move it's new database to it's software stack. The database was not used as cache but for running Enterprise Application satisfying both OLTP and OLAP demands on the same database.
As oracle announced the new Oracle 12c in late 2012 there the 'c' was for cloud based computing, means the simplification of creating (more...)
Matrix : What you must learn is that these rules are no different than rules of a computer system. Some of them can be bent, others can be broken. Understand?
Usually an unique index grants the uniqueness of all rows in a specific table which have non-null values; But (more...)
Since I joined a Big Data Event : Frankfurter Datenbanktage 2013 - I started to take also a look to non-relational technics too. The RDBMS is not for every asepct the correct and fitting and fulfilling answer to all data related IT challenges.
Frequently I wondered about how facebook (more...)
Gerhard a colleague is dealing with postgres databases and was very suprised how many features are very oracle like. For example the same concept of Sequences as in Oracle. But then he detected the postgres enum native type support in postgres and asked me if the same feature would exist in Oracle.
After a successful migration from Oracle 10gR2 to Oracle 11gR2, I observed a very odd behavior executing a query; On first execution the query run fast - means 0.3 s; On second not faster but with tremendous reduced speed - approximate 20 s;
Now this behavior is the opposite I experienced with complex queries (lot of joins, lot of predicates) , the first time of execution needs the extra cost of hard parsing and disk reads if the data is not in cache. the second time even the query run initial several seconds it run in a fraction of (more...)
Currently I am testing/migrating an Oracle 11.2 Installation of our Appliction;
And found by the way a very helpful resource for Oracle Upgrades to 11GR2;
For example a real helpful and detailed document is this : 11g Release 2 Upgrade Workshop Presentation