Table Maintenance Statements The  sampled_pages_read  and  sampled_pages_skipped INNODB_METRICS  counters can be used to monitor sampling of  InnoDB  data pages. (For general  INNODB_METRICS  counter usage information, see Section 26.4.23, “The INFORMATION_SCHEMA INNODB_METRICS Table” .) The following example demonstrates sampling counter usage, which requires enabling the counters prior to generating histogram statistics. This formula approximates a sampling rate based on the sampling counter data: A sampling rate based on sampling counter data is roughly the same as the  sampling-rate  value in the HISTOGRAM  column of  INFORMATION_SCHEMA.COLUMN_STATISTICS  table. For information about memory allocations performed for histogram generation, monitor the Performance Schema  memory/sql/histograms  instrument. See Section 27.12.20.10, “Memory Summary Tables” . ANALYZE TABLE  clears table statistics from the  INFORMATION_SCHEMA.INNODB_TABLESTATS  table and sets the  STATS_INITIALIZED  column to  Uninitialized . Statistics are collected again the next time the table is accessed. CHECK TABLE  checks a table or tables for errors.  CHECK TABLE  can also check views for problems, such as tables that are referenced in the view definition that no longer exist. To check a table, you must have some privilege for it. 2890 13.7.3.2 CHECK TABLE Statement Other Considerations mysql>  SET GLOBAL innodb_monitor_enable = ’sampled%’; mysql>  USE employees; mysql>  ANALYZE TABLE employees UPDATE HISTOGRAM ON birth_date WITH 16 BUCKETS\G *************************** 1. row *************************** Table: employees.employees Op: histogram Msg_type: status Msg_text: Histogram statistics created for column ’birth_date’. mysql>  USE INFORMATION_SCHEMA; mysql>  SELECT NAME, COUNT FROM INNODB_METRICS WHERE NAME LIKE ’sampled%’\G *************************** 1. row ***************************  NAME: sampled_pages_read COUNT: 43 *************************** 2. row ***************************  NAME: sampled_pages_skipped COUNT: 843 CHECK TABLE  tbl_name  [,  tbl_name ] ... [ option ] ... option : { FOR UPGRADE | QUICK | FAST | MEDIUM | EXTENDED | CHANGED } sampling rate = sampled_page_read/(sampled_pages_read + sampled_pages_skipped)