InnoDB Monitors

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InnoDB Monitors

InnoDB allows you to dump information on it's internal data dictionary out to stderr, by creating specific InnoDB monitor tables. Specifically the innodb_table_monitor and innodb_tablespace_monitor tables. In the following we will use output created via these tables based upon the sample "sakila" database, and give details on how to attempt to correlate the information between the different outputs.

InnoDB Tablespace Monitor

In order to invoke InnoDB to output it's data dictionary information on the tablespace, you must create an InnoDB table, as such: 

create table innodb_tablespace_monitor (a int) engine = innodb;

InnoDB will then dump the tablespace information to either the error log, or the console (if started without log-error).

Note: This only works fully when not using the innodb_file_per_table option, as it only dumps information on the shared tablespace, and not individual "tablespaces". 

================================================
060403 14:20:31 INNODB TABLESPACE MONITOR OUTPUT
================================================
FILE SPACE INFO: id 0
size 1152, free limit 832, free extents 3
not full frag extents 4: used pages 202, full frag extents 2
first seg id not used 0 114
SEGMENT id 0 86 space 0; page 209; res 28 used 28; full ext 0
fragm pages 28; free extents 0; not full extents 0: pages 0
SEGMENT id 0 87 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 88 space 0; page 209; res 16 used 16; full ext 0
fragm pages 16; free extents 0; not full extents 0: pages 0
SEGMENT id 0 89 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 90 space 0; page 209; res 16 used 16; full ext 0
fragm pages 16; free extents 0; not full extents 0: pages 0
SEGMENT id 0 91 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 92 space 0; page 209; res 13 used 13; full ext 0
fragm pages 13; free extents 0; not full extents 0: pages 0
SEGMENT id 0 93 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 94 space 0; page 209; res 3 used 3; full ext 0
fragm pages 3; free extents 0; not full extents 0: pages 0
SEGMENT id 0 95 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 96 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 97 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 98 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 99 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 100 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 101 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 102 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 103 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 104 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 109 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 110 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 111 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 112 space 0; page 209; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 113 space 0; page 209; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 1 space 0; page 2; res 2 used 2; full ext 0
fragm pages 2; free extents 0; not full extents 0: pages 0
SEGMENT id 0 2 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 3 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 4 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 5 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 6 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 7 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 8 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 9 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 10 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 11 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 12 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 13 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 14 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 15 space 0; page 2; res 160 used 160; full ext 2
fragm pages 32; free extents 0; not full extents 0: pages 0
SEGMENT id 0 17 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 18 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 19 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 20 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 21 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 22 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 23 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 24 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 25 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 26 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 27 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 28 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 29 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 30 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 31 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 32 space 0; page 2; res 4 used 4; full ext 0
fragm pages 4; free extents 0; not full extents 0: pages 0
SEGMENT id 0 33 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 34 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 35 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 36 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 37 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 38 space 0; page 2; res 2 used 2; full ext 0
fragm pages 2; free extents 0; not full extents 0: pages 0
SEGMENT id 0 39 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 40 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 41 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 42 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 43 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 44 space 0; page 2; res 4 used 4; full ext 0
fragm pages 4; free extents 0; not full extents 0: pages 0
SEGMENT id 0 45 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 46 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 47 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 48 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 49 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 50 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 51 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 52 space 0; page 2; res 11 used 11; full ext 0
fragm pages 11; free extents 0; not full extents 0: pages 0
SEGMENT id 0 53 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 54 space 0; page 2; res 2 used 2; full ext 0
fragm pages 2; free extents 0; not full extents 0: pages 0
SEGMENT id 0 55 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 56 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 57 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 58 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 59 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 60 space 0; page 2; res 11 used 11; full ext 0
fragm pages 11; free extents 0; not full extents 0: pages 0
SEGMENT id 0 61 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 62 space 0; page 2; res 4 used 4; full ext 0
fragm pages 4; free extents 0; not full extents 0: pages 0
SEGMENT id 0 63 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 64 space 0; page 2; res 3 used 3; full ext 0
fragm pages 3; free extents 0; not full extents 0: pages 0
SEGMENT id 0 65 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 66 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 67 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 68 space 0; page 2; res 10 used 10; full ext 0
fragm pages 10; free extents 0; not full extents 0: pages 0
SEGMENT id 0 69 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 70 space 0; page 2; res 4 used 4; full ext 0
fragm pages 4; free extents 0; not full extents 0: pages 0
SEGMENT id 0 71 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 72 space 0; page 2; res 6 used 6; full ext 0
fragm pages 6; free extents 0; not full extents 0: pages 0
SEGMENT id 0 73 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 74 space 0; page 2; res 0 used 0; full ext 0
fragm pages 0; free extents 0; not full extents 0: pages 0
SEGMENT id 0 75 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 76 space 0; page 2; res 96 used 47; full ext 0
fragm pages 32; free extents 0; not full extents 1: pages 15
SEGMENT id 0 77 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 78 space 0; page 2; res 10 used 10; full ext 0
fragm pages 10; free extents 0; not full extents 0: pages 0
SEGMENT id 0 79 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 80 space 0; page 2; res 10 used 10; full ext 0
fragm pages 10; free extents 0; not full extents 0: pages 0
SEGMENT id 0 81 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 82 space 0; page 2; res 16 used 16; full ext 0
fragm pages 16; free extents 0; not full extents 0: pages 0
SEGMENT id 0 83 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
SEGMENT id 0 84 space 0; page 2; res 96 used 53; full ext 0
fragm pages 32; free extents 0; not full extents 1: pages 21
SEGMENT id 0 85 space 0; page 2; res 1 used 1; full ext 0
fragm pages 1; free extents 0; not full extents 0: pages 0
NUMBER of file segments: 108
Validating tablespace
Validation ok
---------------------------------------
END OF INNODB TABLESPACE MONITOR OUTPUT
=======================================

Now let's break down what this means for each segment. Right near the end we have SEGMENT id 0 84: 

SEGMENT id 0 84 space 0; page 2; res 96 used 53; full ext 0
fragm pages 32; free extents 0; not full extents 1: pages 21

Space 0, page 2 means that the inode of the segment is on page 2 of space 0. The system tablespace (ibdata files) always have the id 0.

res means how many pages we have allocated for the segment.

used means how many of these pages are actually used by the segment at the moment.

So for this segment we have 96 pages allocated, but only 53 are being used currently, leaving 43 pages unused.

full ext means that 0 extents are completely used.

fragm pages means that additionally we have used all of the first 32 pages that InnoDB first allocates for the segment.

free extents means the number of those extents that are allocated for the segment, but where none of the pages is used.

not full extents tells you the number of those extents that are allocated for the segment, where some of the pages are used but not all.

pages tells you how many pages are used within those extents.

An extent in InnoDB is always 64 pages at a size of 16kb - 1 MB.

The tablespace is divided into these 64 page extents. When a segment grows it starts at a single page, and InnoDB allocates the first 32 pages for it individually. After that, InnoDB allocates complete 64 page extents.

This is shown with the number of pages reserved - 32 initial pages + 64 pages for the next extent.

InnoDB bases it's internal tablespace management as a filesystem. The analogy between an OS file system and an InnoDB tablespace is: 

File system              <-> InnoDB
----------------------------------------------
disk partition           <-> tablespace
file                     <-> segment
inode                    <-> fsp0fsp.c 'inode'
fs space allocation unit <-> extent
disk block               <-> page (16 kB)

So currently, the table in question (SEGMENT id 0 84) is 96 pages in size, or 1.5Mb, and has 43 pages free, or 688Kb.

Now that we have this information, how do we try to find out which table this is? Let's move on to the innodb_table_monitor output.

InnoDB Table Monitor

To direct the output of the InnoDB Table Monitor to the erro log create the following table: 

create table innodb_table_monitor (a int) engine = innodb;

This produces the following output for the Sakila sample database: 

===========================================
060403 14:29:35 INNODB TABLE MONITOR OUTPUT
===========================================
--------------------------------------
TABLE: name SYS_FOREIGN, id 0 11, columns 8, indexes 3, appr.rows 22
  COLUMNS: ID: DATA_VARCHAR prtype 1 len 0 prec 0; FOR_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; REF_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; N_COLS: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name ID_IND, id 0 11, fields 1/6, type 3
   root page 46, appr.key vals 22, leaf pages 1, size pages 1
   FIELDS:  ID DB_TRX_ID DB_ROLL_PTR FOR_NAME REF_NAME N_COLS
  INDEX: name FOR_IND, id 0 12, fields 1/2, type 0
   root page 47, appr.key vals 11, leaf pages 1, size pages 1
   FIELDS:  FOR_NAME ID
  INDEX: name REF_IND, id 0 13, fields 1/2, type 0
   root page 48, appr.key vals 12, leaf pages 1, size pages 1
   FIELDS:  REF_NAME ID
--------------------------------------
TABLE: name SYS_FOREIGN_COLS, id 0 12, columns 8, indexes 1, appr.rows 22
  COLUMNS: ID: DATA_VARCHAR prtype 1 len 0 prec 0; POS: DATA_INT len 4 prec 0; FOR_COL_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; REF_COL_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name ID_IND, id 0 14, fields 2/6, type 3
   root page 49, appr.key vals 22, leaf pages 1, size pages 1
   FIELDS:  ID POS DB_TRX_ID DB_ROLL_PTR FOR_COL_NAME REF_COL_NAME
--------------------------------------
TABLE: name sakila/actor, id 0 14, columns 8, indexes 2, appr.rows 200
  COLUMNS: actor_id: DATA_INT len 2 prec 0; first_name: type 12 len 135 prec 0; last_name: type 12 len 135 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 16, fields 1/6, type 3
   root page 51, appr.key vals 200, leaf pages 1, size pages 1
   FIELDS:  actor_id DB_TRX_ID DB_ROLL_PTR first_name last_name last_update
  INDEX: name idx_actor_last_name, id 0 17, fields 1/2, type 0
   root page 52, appr.key vals 121, leaf pages 1, size pages 1
   FIELDS:  last_name actor_id
  FOREIGN KEY CONSTRAINT sakila/fk_film_actor_actor: sakila/film_actor ( actor_id )
             REFERENCES sakila/actor ( actor_id )
--------------------------------------
TABLE: name sakila/address, id 0 15, columns 12, indexes 2, appr.rows 589
  COLUMNS: address_id: DATA_INT len 2 prec 0; address: type 12 len 150 prec 0; address2: type 12 len 150 prec 0; district: type 12 len 60 prec 0; city_id: DATA_INT len 2 prec 0; postal_code: type 12 len 30 prec 0; phone: type 12 len 60 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 18, fields 1/10, type 3
   root page 53, appr.key vals 589, leaf pages 4, size pages 5
   FIELDS:  address_id DB_TRX_ID DB_ROLL_PTR address address2 district city_id postal_code phone last_update
  INDEX: name idx_fk_city_id, id 0 19, fields 1/2, type 0
   root page 54, appr.key vals 599, leaf pages 1, size pages 1
   FIELDS:  city_id address_id
  FOREIGN KEY CONSTRAINT sakila/fk_address_city: sakila/address ( city_id )
             REFERENCES sakila/city ( city_id )
  FOREIGN KEY CONSTRAINT sakila/fk_customer_address: sakila/customer ( address_id )
             REFERENCES sakila/address ( address_id )
  FOREIGN KEY CONSTRAINT sakila/fk_staff_address: sakila/staff ( address_id )
             REFERENCES sakila/address ( address_id )
  FOREIGN KEY CONSTRAINT sakila/fk_store_address: sakila/store ( address_id )
             REFERENCES sakila/address ( address_id )
--------------------------------------
TABLE: name sakila/category, id 0 16, columns 7, indexes 1, appr.rows 16
  COLUMNS: category_id: DATA_INT len 1 prec 0; name: type 12 len 75 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 20, fields 1/5, type 3
   root page 55, appr.key vals 16, leaf pages 1, size pages 1
   FIELDS:  category_id DB_TRX_ID DB_ROLL_PTR name last_update
  FOREIGN KEY CONSTRAINT sakila/fk_film_category_category: sakila/film_category ( category_id )
             REFERENCES sakila/category ( category_id )
--------------------------------------
TABLE: name sakila/city, id 0 17, columns 8, indexes 2, appr.rows 427
  COLUMNS: city_id: DATA_INT len 2 prec 0; city: type 12 len 150 prec 0; country_id: DATA_INT len 2 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 21, fields 1/6, type 3
   root page 56, appr.key vals 427, leaf pages 2, size pages 3
   FIELDS:  city_id DB_TRX_ID DB_ROLL_PTR city country_id last_update
  INDEX: name idx_fk_country_id, id 0 22, fields 1/2, type 0
   root page 57, appr.key vals 109, leaf pages 1, size pages 1
   FIELDS:  country_id city_id
  FOREIGN KEY CONSTRAINT sakila/fk_city_country: sakila/city ( country_id )
             REFERENCES sakila/country ( country_id )
  FOREIGN KEY CONSTRAINT sakila/fk_address_city: sakila/address ( city_id )
             REFERENCES sakila/city ( city_id )
--------------------------------------
TABLE: name sakila/country, id 0 18, columns 7, indexes 1, appr.rows 109
  COLUMNS: country_id: DATA_INT len 2 prec 0; country: type 12 len 150 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 23, fields 1/5, type 3
   root page 58, appr.key vals 109, leaf pages 1, size pages 1
   FIELDS:  country_id DB_TRX_ID DB_ROLL_PTR country last_update
  FOREIGN KEY CONSTRAINT sakila/fk_city_country: sakila/city ( country_id )
             REFERENCES sakila/country ( country_id )
--------------------------------------
TABLE: name sakila/customer, id 0 19, columns 13, indexes 4, appr.rows 541
  COLUMNS: customer_id: DATA_INT len 2 prec 0; store_id: DATA_INT len 1 prec 0; first_name: type 12 len 135 prec 0; last_name: type 12 len 135 prec 0; email: type 12 len 150 prec 0; address_id: DATA_INT len 2 prec 0; active: DATA_INT len 1 prec 0; create_date: DATA_INT len 8 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 24, fields 1/11, type 3
   root page 59, appr.key vals 541, leaf pages 4, size pages 5
   FIELDS:  customer_id DB_TRX_ID DB_ROLL_PTR store_id first_name last_name email address_id active create_date last_update
  INDEX: name idx_fk_store_id, id 0 25, fields 1/2, type 0
   root page 60, appr.key vals 2, leaf pages 1, size pages 1
   FIELDS:  store_id customer_id
  INDEX: name idx_fk_address_id, id 0 26, fields 1/2, type 0
   root page 61, appr.key vals 599, leaf pages 1, size pages 1
   FIELDS:  address_id customer_id
  INDEX: name idx_last_name, id 0 27, fields 1/2, type 0
   root page 62, appr.key vals 599, leaf pages 1, size pages 1
   FIELDS:  last_name customer_id
  FOREIGN KEY CONSTRAINT sakila/fk_customer_address: sakila/customer ( address_id )
             REFERENCES sakila/address ( address_id )
  FOREIGN KEY CONSTRAINT sakila/fk_customer_store: sakila/customer ( store_id )
             REFERENCES sakila/store ( store_id )
  FOREIGN KEY CONSTRAINT sakila/fk_payment_customer: sakila/payment ( customer_id )
             REFERENCES sakila/customer ( customer_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_customer: sakila/rental ( customer_id )
             REFERENCES sakila/customer ( customer_id )
--------------------------------------
TABLE: name sakila/film, id 0 20, columns 17, indexes 4, appr.rows 1022
  COLUMNS: film_id: DATA_INT len 2 prec 0; title: type 12 len 765 prec 0; description: type 5 len 10 prec 0; release_year: DATA_INT len 1 prec 0; language_id: DATA_INT len 1 prec 0; original_language_id: DATA_INT len 1 prec 0; rental_duration: DATA_INT len 1 prec 0; rental_rate: type 3 len 2 prec 0; length: DATA_INT len 2 prec 0; replacement_cost: type 3 len 3 prec 0; rating: DATA_INT len 1 prec 0; special_features: DATA_INT len 1 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 28, fields 1/15, type 3
   root page 63, appr.key vals 1022, leaf pages 11, size pages 12
   FIELDS:  film_id DB_TRX_ID DB_ROLL_PTR title description release_year language_id original_language_id rental_duration rental_rate length replacement_cost rating special_features last_update
  INDEX: name idx_title, id 0 29, fields 1/2, type 0
   root page 192, appr.key vals 713, leaf pages 2, size pages 3
   FIELDS:  title film_id
  INDEX: name idx_fk_language_id, id 0 30, fields 1/2, type 0
   root page 193, appr.key vals 1, leaf pages 1, size pages 1
   FIELDS:  language_id film_id
  INDEX: name idx_fk_original_language_id, id 0 31, fields 1/2, type 0
   root page 194, appr.key vals 1, leaf pages 1, size pages 1
   FIELDS:  original_language_id film_id
  FOREIGN KEY CONSTRAINT sakila/fk_film_language: sakila/film ( language_id )
             REFERENCES sakila/language ( language_id )
  FOREIGN KEY CONSTRAINT sakila/fk_film_language_original: sakila/film ( original_language_id )
             REFERENCES sakila/language ( language_id )
  FOREIGN KEY CONSTRAINT sakila/fk_film_actor_film: sakila/film_actor ( film_id )
             REFERENCES sakila/film ( film_id )
  FOREIGN KEY CONSTRAINT sakila/fk_film_category_film: sakila/film_category ( film_id )
             REFERENCES sakila/film ( film_id )
  FOREIGN KEY CONSTRAINT sakila/fk_inventory_film: sakila/inventory ( film_id )
             REFERENCES sakila/film ( film_id )
--------------------------------------
TABLE: name sakila/film_actor, id 0 21, columns 7, indexes 2, appr.rows 5143
  COLUMNS: actor_id: DATA_INT len 2 prec 0; film_id: DATA_INT len 2 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 32, fields 2/5, type 3
   root page 195, appr.key vals 5143, leaf pages 11, size pages 12
   FIELDS:  actor_id film_id DB_TRX_ID DB_ROLL_PTR last_update
  INDEX: name idx_fk_film_id, id 0 33, fields 1/2, type 0
   root page 196, appr.key vals 985, leaf pages 4, size pages 5
   FIELDS:  film_id actor_id
  FOREIGN KEY CONSTRAINT sakila/fk_film_actor_actor: sakila/film_actor ( actor_id )
             REFERENCES sakila/actor ( actor_id )
  FOREIGN KEY CONSTRAINT sakila/fk_film_actor_film: sakila/film_actor ( film_id )
             REFERENCES sakila/film ( film_id )
--------------------------------------
TABLE: name sakila/film_category, id 0 22, columns 7, indexes 2, appr.rows 895
  COLUMNS: film_id: DATA_INT len 2 prec 0; category_id: DATA_INT len 1 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 34, fields 2/5, type 3
   root page 197, appr.key vals 895, leaf pages 3, size pages 4
   FIELDS:  film_id category_id DB_TRX_ID DB_ROLL_PTR last_update
  INDEX: name fk_film_category_category, id 0 35, fields 1/2, type 0
   root page 198, appr.key vals 16, leaf pages 1, size pages 1
   FIELDS:  category_id film_id
  FOREIGN KEY CONSTRAINT sakila/fk_film_category_film: sakila/film_category ( film_id )
             REFERENCES sakila/film ( film_id )
  FOREIGN KEY CONSTRAINT sakila/fk_film_category_category: sakila/film_category ( category_id )
             REFERENCES sakila/category ( category_id )
--------------------------------------
TABLE: name sakila/innodb_table_monitor, id 0 31, columns 5, indexes 1, appr.rows 0
  COLUMNS: a: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name GEN_CLUST_INDEX, id 0 57, fields 0/4, type 1
   root page 594, appr.key vals 0, leaf pages 1, size pages 1
   FIELDS:  DB_ROW_ID DB_TRX_ID DB_ROLL_PTR a
--------------------------------------
TABLE: name sakila/inventory, id 0 23, columns 8, indexes 3, appr.rows 5007
  COLUMNS: inventory_id: DATA_INT len 3 prec 0; film_id: DATA_INT len 2 prec 0; store_id: DATA_INT len 1 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 36, fields 1/6, type 3
   root page 199, appr.key vals 5007, leaf pages 10, size pages 11
   FIELDS:  inventory_id DB_TRX_ID DB_ROLL_PTR film_id store_id last_update
  INDEX: name idx_fk_film_id, id 0 37, fields 1/2, type 0
   root page 200, appr.key vals 981, leaf pages 4, size pages 5
   FIELDS:  film_id inventory_id
  INDEX: name idx_store_id_film_id, id 0 38, fields 2/3, type 0
   root page 201, appr.key vals 2419, leaf pages 6, size pages 7
   FIELDS:  store_id film_id inventory_id
  FOREIGN KEY CONSTRAINT sakila/fk_inventory_store: sakila/inventory ( store_id )
             REFERENCES sakila/store ( store_id )
  FOREIGN KEY CONSTRAINT sakila/fk_inventory_film: sakila/inventory ( film_id )
             REFERENCES sakila/film ( film_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_inventory: sakila/rental ( inventory_id )
             REFERENCES sakila/inventory ( inventory_id )
--------------------------------------
TABLE: name sakila/language, id 0 24, columns 7, indexes 1, appr.rows 6
  COLUMNS: language_id: DATA_INT len 1 prec 0; name: DATA_MYSQL len 60 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 39, fields 1/5, type 3
   root page 202, appr.key vals 6, leaf pages 1, size pages 1
   FIELDS:  language_id DB_TRX_ID DB_ROLL_PTR name last_update
  FOREIGN KEY CONSTRAINT sakila/fk_film_language: sakila/film ( language_id )
             REFERENCES sakila/language ( language_id )
  FOREIGN KEY CONSTRAINT sakila/fk_film_language_original: sakila/film ( original_language_id )
             REFERENCES sakila/language ( language_id )
--------------------------------------
TABLE: name sakila/payment, id 0 25, columns 11, indexes 4, appr.rows 16451
  COLUMNS: payment_id: DATA_INT len 2 prec 0; customer_id: DATA_INT len 2 prec 0; staff_id: DATA_INT len 1 prec 0; rental_id: DATA_INT len 4 prec 0; amount: type 3 len 3 prec 0; payment_date: DATA_INT len 8 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 40, fields 1/9, type 3
   root page 203, appr.key vals 16451, leaf pages 47, size pages 97
   FIELDS:  payment_id DB_TRX_ID DB_ROLL_PTR customer_id staff_id rental_id amount payment_date last_update
  INDEX: name idx_fk_staff_id, id 0 41, fields 1/2, type 0
   root page 204, appr.key vals 3, leaf pages 10, size pages 11
   FIELDS:  staff_id payment_id
  INDEX: name idx_fk_customer_id, id 0 42, fields 1/2, type 0
   root page 205, appr.key vals 549, leaf pages 10, size pages 11
   FIELDS:  customer_id payment_id
  INDEX: name fk_payment_rental, id 0 43, fields 1/2, type 0
   root page 206, appr.key vals 16071, leaf pages 16, size pages 17
   FIELDS:  rental_id payment_id
  FOREIGN KEY CONSTRAINT sakila/fk_payment_rental: sakila/payment ( rental_id )
             REFERENCES sakila/rental ( rental_id )
  FOREIGN KEY CONSTRAINT sakila/fk_payment_customer: sakila/payment ( customer_id )
             REFERENCES sakila/customer ( customer_id )
  FOREIGN KEY CONSTRAINT sakila/fk_payment_staff: sakila/payment ( staff_id )
             REFERENCES sakila/staff ( staff_id )
--------------------------------------
TABLE: name sakila/rental, id 0 26, columns 11, indexes 5, appr.rows 16305
  COLUMNS: rental_id: DATA_INT len 4 prec 0; rental_date: DATA_INT len 8 prec 0; inventory_id: DATA_INT len 3 prec 0; customer_id: DATA_INT len 2 prec 0; return_date: DATA_INT len 8 prec 0; staff_id: DATA_INT len 1 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 44, fields 1/9, type 3
   root page 207, appr.key vals 16305, leaf pages 53, size pages 97
   FIELDS:  rental_id DB_TRX_ID DB_ROLL_PTR rental_date inventory_id customer_id return_date staff_id last_update
  INDEX: name rental_date, id 0 45, fields 3/4, type 2
   root page 208, appr.key vals 17655, leaf pages 28, size pages 29
   FIELDS:  rental_date inventory_id customer_id rental_id
  INDEX: name idx_fk_inventory_id, id 0 46, fields 1/2, type 0
   root page 210, appr.key vals 4467, leaf pages 16, size pages 17
   FIELDS:  inventory_id rental_id
  INDEX: name idx_fk_customer_id, id 0 47, fields 1/2, type 0
   root page 211, appr.key vals 589, leaf pages 16, size pages 17
   FIELDS:  customer_id rental_id
  INDEX: name idx_fk_staff_id, id 0 48, fields 1/2, type 0
   root page 212, appr.key vals 1, leaf pages 13, size pages 14
   FIELDS:  staff_id rental_id
  FOREIGN KEY CONSTRAINT sakila/fk_rental_staff: sakila/rental ( staff_id )
             REFERENCES sakila/staff ( staff_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_inventory: sakila/rental ( inventory_id )
             REFERENCES sakila/inventory ( inventory_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_customer: sakila/rental ( customer_id )
             REFERENCES sakila/customer ( customer_id )
  FOREIGN KEY CONSTRAINT sakila/fk_payment_rental: sakila/payment ( rental_id )
             REFERENCES sakila/rental ( rental_id )
--------------------------------------
TABLE: name sakila/staff, id 0 27, columns 15, indexes 3, appr.rows 1
  COLUMNS: staff_id: DATA_INT len 1 prec 0; first_name: type 12 len 135 prec 0; last_name: type 12 len 135 prec 0; address_id: DATA_INT len 2 prec 0; picture: type 5 len 10 prec 0; email: type 12 len 150 prec 0; store_id: DATA_INT len 1 prec 0; active: DATA_INT len 1 prec 0; username: type 12 len 48 prec 0; password: type 12 len 120 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 49, fields 1/13, type 3
   root page 213, appr.key vals 1, leaf pages 3, size pages 4
   FIELDS:  staff_id DB_TRX_ID DB_ROLL_PTR first_name last_name address_id picture email store_id active username password last_update
  INDEX: name idx_fk_store_id, id 0 50, fields 1/2, type 0
   root page 214, appr.key vals 2, leaf pages 1, size pages 1
   FIELDS:  store_id staff_id
  INDEX: name idx_fk_address_id, id 0 51, fields 1/2, type 0
   root page 215, appr.key vals 2, leaf pages 1, size pages 1
   FIELDS:  address_id staff_id
  FOREIGN KEY CONSTRAINT sakila/fk_staff_store: sakila/staff ( store_id )
             REFERENCES sakila/store ( store_id )
  FOREIGN KEY CONSTRAINT sakila/fk_staff_address: sakila/staff ( address_id )
             REFERENCES sakila/address ( address_id )
  FOREIGN KEY CONSTRAINT sakila/fk_payment_staff: sakila/payment ( staff_id )
             REFERENCES sakila/staff ( staff_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_staff: sakila/rental ( staff_id )
             REFERENCES sakila/staff ( staff_id )
  FOREIGN KEY CONSTRAINT sakila/fk_store_staff: sakila/store ( manager_staff_id )
             REFERENCES sakila/staff ( staff_id )
--------------------------------------
TABLE: name sakila/store, id 0 28, columns 8, indexes 3, appr.rows 2
  COLUMNS: store_id: DATA_INT len 1 prec 0; manager_staff_id: DATA_INT len 1 prec 0; address_id: DATA_INT len 2 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 52, fields 1/6, type 3
   root page 216, appr.key vals 2, leaf pages 1, size pages 1
   FIELDS:  store_id DB_TRX_ID DB_ROLL_PTR manager_staff_id address_id last_update
  INDEX: name idx_unique_manager, id 0 53, fields 1/2, type 2
   root page 217, appr.key vals 2, leaf pages 1, size pages 1
   FIELDS:  manager_staff_id store_id
  INDEX: name idx_fk_address_id, id 0 54, fields 1/2, type 0
   root page 218, appr.key vals 2, leaf pages 1, size pages 1
   FIELDS:  address_id store_id
  FOREIGN KEY CONSTRAINT sakila/fk_store_staff: sakila/store ( manager_staff_id )
             REFERENCES sakila/staff ( staff_id )
  FOREIGN KEY CONSTRAINT sakila/fk_store_address: sakila/store ( address_id )
             REFERENCES sakila/address ( address_id )
  FOREIGN KEY CONSTRAINT sakila/fk_customer_store: sakila/customer ( store_id )
             REFERENCES sakila/store ( store_id )
  FOREIGN KEY CONSTRAINT sakila/fk_inventory_store: sakila/inventory ( store_id )
             REFERENCES sakila/store ( store_id )
  FOREIGN KEY CONSTRAINT sakila/fk_staff_store: sakila/staff ( store_id )
             REFERENCES sakila/store ( store_id )
--------------------------------------
TABLE: name test/t3, id 0 13, columns 6, indexes 1, appr.rows 1
  COLUMNS: i: DATA_INT len 4 prec 0; j: DATA_VARCHAR prtype 1 len 4000 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name GEN_CLUST_INDEX, id 0 15, fields 0/5, type 1
   root page 50, appr.key vals 1, leaf pages 1, size pages 1
   FIELDS:  DB_ROW_ID DB_TRX_ID DB_ROLL_PTR i j
-----------------------------------
END OF INNODB TABLE MONITOR OUTPUT
==================================

InnoDB uses clustered indexes, so the actual row data is stored along with the PRIMARY KEY (be this user, or synthetically generated if no PRIMARY KEY was specified). So we are looking for a PRIMARY KEY in the above output that is around 96 pages long, and that has 53 pages free.

First, here is the actual table that we are looking for, sakila.rental: 

TABLE: name sakila/rental, id 0 26, columns 11, indexes 5, appr.rows 16305
  COLUMNS: rental_id: DATA_INT len 4 prec 0; rental_date: DATA_INT len 8 prec 0; inventory_id: DATA_INT len 3 prec 0; customer_id: DATA_INT len 2 prec 0; return_date: DATA_INT len 8 prec 0; staff_id: DATA_INT len 1 prec 0; last_update: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name PRIMARY, id 0 44, fields 1/9, type 3
   root page 207, appr.key vals 16305, leaf pages 53, size pages 97
   FIELDS:  rental_id DB_TRX_ID DB_ROLL_PTR rental_date inventory_id customer_id return_date staff_id last_update
  INDEX: name rental_date, id 0 45, fields 3/4, type 2
   root page 208, appr.key vals 17655, leaf pages 28, size pages 29
   FIELDS:  rental_date inventory_id customer_id rental_id
  INDEX: name idx_fk_inventory_id, id 0 46, fields 1/2, type 0
   root page 210, appr.key vals 4467, leaf pages 16, size pages 17
   FIELDS:  inventory_id rental_id
  INDEX: name idx_fk_customer_id, id 0 47, fields 1/2, type 0
   root page 211, appr.key vals 589, leaf pages 16, size pages 17
   FIELDS:  customer_id rental_id
  INDEX: name idx_fk_staff_id, id 0 48, fields 1/2, type 0
   root page 212, appr.key vals 1, leaf pages 13, size pages 14
   FIELDS:  staff_id rental_id
  FOREIGN KEY CONSTRAINT sakila/fk_rental_staff: sakila/rental ( staff_id )
             REFERENCES sakila/staff ( staff_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_inventory: sakila/rental ( inventory_id )
             REFERENCES sakila/inventory ( inventory_id )
  FOREIGN KEY CONSTRAINT sakila/fk_rental_customer: sakila/rental ( customer_id )
             REFERENCES sakila/customer ( customer_id )
  FOREIGN KEY CONSTRAINT sakila/fk_payment_rental: sakila/payment ( rental_id )
             REFERENCES sakila/rental ( rental_id )

Among the wealth of obvious information here, for INDEX: name PRIMARY you can see: 

 INDEX: name PRIMARY, id 0 44, fields 1/9, type 3
  root page 207, appr.key vals 16305, leaf pages 53, size pages 97
  FIELDS:  rental_id DB_TRX_ID DB_ROLL_PTR rental_date inventory_id customer_id return_date staff_id last_update

leaf pages is the number of used pages used by the clustered index

size pages is the overall number of pages allocated to the clustered index

Note: It is more difficult to correlate the relations between small tables (1 page allocated each for example).

This output also gives information on the internal data dictionary tables used by InnoDB: 

--------------------------------------
TABLE: name SYS_FOREIGN, id 0 11, columns 8, indexes 3, appr.rows 22
  COLUMNS: ID: DATA_VARCHAR prtype 1 len 0 prec 0; FOR_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; REF_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; N_COLS: DATA_INT len 4 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name ID_IND, id 0 11, fields 1/6, type 3
   root page 46, appr.key vals 22, leaf pages 1, size pages 1
   FIELDS:  ID DB_TRX_ID DB_ROLL_PTR FOR_NAME REF_NAME N_COLS
  INDEX: name FOR_IND, id 0 12, fields 1/2, type 0
   root page 47, appr.key vals 11, leaf pages 1, size pages 1
   FIELDS:  FOR_NAME ID
  INDEX: name REF_IND, id 0 13, fields 1/2, type 0
   root page 48, appr.key vals 12, leaf pages 1, size pages 1
   FIELDS:  REF_NAME ID
--------------------------------------
TABLE: name SYS_FOREIGN_COLS, id 0 12, columns 8, indexes 1, appr.rows 22
  COLUMNS: ID: DATA_VARCHAR prtype 1 len 0 prec 0; POS: DATA_INT len 4 prec 0; FOR_COL_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; REF_COL_NAME: DATA_VARCHAR prtype 1 len 0 prec 0; DB_ROW_ID: DATA_SYS prtype 8 len 6 prec 0; DB_TRX_ID: DATA_SYS prtype 8 len 6 prec 0; DB_ROLL_PTR: DATA_SYS prtype 8 len 7 prec 0; 
  INDEX: name ID_IND, id 0 14, fields 2/6, type 3
   root page 49, appr.key vals 22, leaf pages 1, size pages 1
   FIELDS:  ID POS DB_TRX_ID DB_ROLL_PTR FOR_COL_NAME REF_COL_NAME
--------------------------------------
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