If you have installed SQL Server using my previous post Install SQL Server 2017 on Linux, this post is to describe the directory structure of SQL Server on Linux. MSSQL binaries are installed under /opt/mssql folder. This folder further includes mssql binaries & libraries sub-folders:- MSSQL Binaries /opt/mssql/bin :- MSSQL Libraries /opt/mssql/lib :- Then comes…
This post is to guide SQL Server 2017 installation on Linux. You can create a Linux VM following my previous post of Installing Linux 7 on Oracle VirtualBox. Once the Linux VM is build follow the instructions below to install SQL Server latest release. Step 1: Download the Microsoft SQL Server Red Hat repository configuration…
The Row Cache or Data Dictionary Cache is a memory area in the shared pool that holds data dictionary information to reduce physical I/O on the data dictionary tables. The row cache lock is used primarily to serialize changes to the data dictionary and is waited on when a lock on a data dictionary cache…
When a user session commits, the session’s redo information needs to be flushed from memory to the redo logfile to make it permanent. At the time of commit, the user session will post the LGWR to write the log buffer (containing the current unwritten redo, including this session’s redo information) to the redo log file.…
log file switch (archiving needed) Waiting for a log switch because the log that the LGWR will be switching into has not been archived yet. Check the alert file to make sure that archiving has not stopped due to a failed archive write. To speed archiving, consider adding more archive processes or putting the archive…
Library cache pins are used to manage library cache concurrency. Pinning an object causes the heaps to be loaded into memory (if not already loaded). PINS can be acquired in NULL, SHARE or EXCLUSIVE modes and can be considered like a special form of lock. A wait for a “library cache pin” implies some other…
The library cache lock controls the concurrency between clients of the library cache by acquiring a lock on the object handle so that either: One client can prevent other clients from accessing the same object The client can maintain a dependency for a long time (no other client can change the object). This lock is…
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…
Oracle Database Internal Mechanism 