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--
-- View: innodb_buffer_stats_by_schema
-- 
-- Summarizes the output of the INFORMATION_SCHEMA.INNODB_BUFFER_PAGE 
-- table, aggregating by schema
--
-- 
-- mysql> select * from innodb_buffer_stats_by_schema;
-- +--------------------------+------------+------------+-------+--------------+-----------+-------------+
-- | object_schema            | allocated  | data       | pages | pages_hashed | pages_old | rows_cached |
-- +--------------------------+------------+------------+-------+--------------+-----------+-------------+
-- | mem30_trunk__instruments | 1.69 MiB   | 510.03 KiB |   108 |          108 |       108 |        3885 |
-- | InnoDB System            | 688.00 KiB | 351.62 KiB |    43 |           43 |        43 |         862 |
-- | mem30_trunk__events      | 80.00 KiB  | 21.61 KiB  |     5 |            5 |         5 |         229 |
-- +--------------------------+------------+------------+-------+--------------+-----------+-------------+
--
CREATE OR REPLACE
  ALGORITHM = TEMPTABLE
  DEFINER = 'mysql.sys'@'localhost'
  SQL SECURITY INVOKER 
VIEW innodb_buffer_stats_by_schema (
  object_schema,
  allocated,
  data,
  pages,
  pages_hashed,
  pages_old,
  rows_cached
) AS
SELECT IF(LOCATE('.', ibp.table_name) = 0, 'InnoDB System', REPLACE(SUBSTRING_INDEX(ibp.table_name, '.', 1), '`', '')) AS object_schema,
       format_bytes(SUM(IF(ibp.compressed_size = 0, 16384, compressed_size))) AS allocated,
       format_bytes(SUM(ibp.data_size)) AS data,
       COUNT(ibp.page_number) AS pages,
       COUNT(IF(ibp.is_hashed = 'YES', 1, NULL)) AS pages_hashed,
       COUNT(IF(ibp.is_old = 'YES', 1, NULL)) AS pages_old,
       ROUND(SUM(ibp.number_records)/COUNT(DISTINCT ibp.index_name)) AS rows_cached 
  FROM information_schema.innodb_buffer_page ibp 
 WHERE table_name IS NOT NULL
 GROUP BY object_schema
 ORDER BY SUM(IF(ibp.compressed_size = 0, 16384, compressed_size)) DESC;