Analyzing buffer cache contents

In this recipe, we will be discussing how to analyze the content that resides in PostgreSQL shared buffers.

Getting ready

To analyze the shared buffer contents, PostgreSQL provides an extension called pg_buffercache, and we also use the CREATE EXTENSION command. This extension reports the buffer details such as which relation holds the number of buffers in the memory, what buffers are dirty at this moment, and what is a specific buffer's usage count.

In PostgreSQL, shared buffers are not specific to any database as they are managed at cluster level. Hence, while querying the pg_buffercache we may get relation details that are from other databases too. Also, it is not recommended to query the pg_buffercache too frequently as it needs to handle buffer management locks, to get the buffer's current status.

How to do it...

Let's install the pg_buffercache extension and then query the view as follows:

postgres=# CREATE EXTENSION pg_buffercache;
CREATE EXTENSION
postgres...