Buffer busy waits – Oracle Wait Event

Buffer busy wait happens when a session wants to access a database block in the buffer cache but it cannot as the buffer is “busy”. The two main cases where this can occur are: Another session is reading the block into the buffer Another session holds the buffer in an incompatible mode to our request…

ORA-12547: TNS:lost contact

This is a quick note to cover ORA-12547: TNS:lost contact error, I would try to include all possible causes of ORA-12547: TNS:lost contact error so that this post itself could assist you in sorting the issue. ORA-12547: TNS:lost contact error could be due to any of the following reasons:- Incorrect permissions on the ORACLE executable.…

Table Access by Rowid

Rowid is an internal representation of the storage location of data. The rowid of a row specifies the data file and data block containing the row and the location of the row in that block. Locating a row by specifying its rowid is the fastest way to retrieve a single row because it specifies the…

12c New Features – Database In-Memory

Here comes the most awaited feature with the release of 12.1.0.2 patchset – Database In-Memory. In this post we will first dwell upon the internals of this feature and then enable this feature in our test environment to benchmark the performance gain. This article assumes that the reader is well aware of the Oracle 11g Memory…