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