This Series of posts would be to cover internals of MySQL Database. Once we understand the internals we would start with installation, then basic administration and finally performance tuning & troubleshooting. The list of articles on MySQL posted on this blog would also be linked below:-
Without further ado, following are the steps to construct your own lab with a 2 node 12c RAC on Linux 6 using Oracle Virtual Box. You can download the required software from below links:- Oracle Linux 7 Oracle VirtualBox Grid Infrastructure 12cR1 Oracle 12cR1 To give you an overview, this is what we are going to…
Without further ado, following are the steps to construct your own lab with a 2 node 12c RAC on Linux 6 using Oracle Virtual Box. You can download the required software from below links:- Oracle Linux 6 Oracle VirtualBox Grid Infrastructure 12cR1 Oracle 12cR1 To give you an overview, this is what we are going to…
This is a quick post on installing Oracle Linux 6 on VirtualBox. This post was originally intended to create a VM (1st node) of a RAC setup. You can download the required software from below links:- Oracle Linux 6 Oracle VirtualBox STEP 1 – Oracle VirtualBox Installation. Run the setup from the downloaded Oracle VirtualBox…
This is a quick post about installing Oracle Linux 7 on VirtualBox VM. We would start by installing Oracle Linux 7 using a Oracle VM Virtual Box:- First of all download Oracle VM Virtual BOX (comment below if you aren’t able to download a copy) compatible to your operating system. For instance in my env. the…
An index skip scan occurs when the initial column of a composite index is “skipped” or not specified in the query. Basically skip scanning lets a composite index be split logically into smaller sub-indexes, making every sub-index a viable candidate to be used by optimizer to come up with an efficient plan. The number of logical…
Index Fast Full Scans are similar to Index Full Scans i.e they read index blocks in unsorted order, as they exist on disk.This scan does not use the index to probe the table, but reads the index instead of the table, essentially using the index itself as a table.
As the name suggests, Index Full Scans are Index Scans where the entire index is scanned in order. Following are the situations where optimizer chooses Index Full Scans:- A predicate references a column in the index. This column need not be the leading column. No predicate is specified and all columns in the table and…
Optimizer chooses Index Range Scans for selective queries which have bounded as well as unbounded data. Thus for every predicate clause having >,>=,<,<= condition on an indexed column, Oracle optimizer would go for Index Range Scans unless fetching large amount of data or unselective query which favours FTS. Following are the situations where optimizer chooses…
Index Unique Scans returns at most 1 rowid, this means that whenever the condition in WHERE clause guarantees that only one row would be returned Oracle optimizer chooses Index Unique Scans. To summarize this, Index Unique Scan access path is used when all columns of a unique (B-tree) index or an index created as a…
Oracle Database Internal Mechanism 