These views summarize the information in the INFORMATION_SCHEMA INNODB_BUFFER_PAGE table, grouped by schema. By default, rows are sorted by descending buffer size.
Querying views that access the INNODB_BUFFER_PAGE table can affect performance. Do not query these views on a production system unless you are aware of the performance impact and have determined it to be acceptable. To avoid impacting performance on a production system, reproduce the issue you want to investigate and query buffer pool statistics on a test instance.
The innodb_buffer_stats_by_schema and x$innodb_buffer_stats_by_schema views have these columns:
object_schema
The schema name for the object, or InnoDB System if the table belongs to the InnoDB storage engine.
allocated
The total number of bytes allocated for the schema.
data
The total number of data bytes allocated for the schema.
pages
The total number of pages allocated for the schema.
pages_hashed
The total number of hashed pages allocated for the schema.
pages_old
The total number of old pages allocated for the schema.
rows_cached
The total number of cached rows for the schema.