14.10.1 TABLE_MAP_EVENT

The first event used in Row Based Replication declares how a table that is about to be changed is defined.

TABLE_MAP_EVENT:

The TABLE_MAP_EVENT defines the structure if the tables that are about to be changed.

Payload

post-header:
    if post_header_len == 6 {
  4              table id
    } else {
  6              table id
    }
  2              flags

payload:
  1              schema name length
  string         schema name
  1              [00]
  1              table name length
  string         table name
  1              [00]
  lenenc-int     column-count
  string.var_len [length=$column-count] column-def
  lenenc-str     column-meta-def
  n              NULL-bitmask, length: (column-count + 8) / 7

Fields

• table_id (6) -- numeric table id

• flags (2) -- flags

• schema_name_length (1) -- length of the schema name

• schema_name (string.var_len) -- [len=schema_name_length] schema name

• table_name_length (1) -- length of the schema name

• table_name (string.var_len) -- [len=table_name_length] table name

• column_count (lenenc_int) -- number of columns in the table map

• column_type_def (string.var_len) -- [len=column_count] array of column definitions, one byte per field type

• column_meta_def (lenenc_str) -- array of metainfo per column, length is the overall length of the metainfo-array in bytes, the length of each metainfo field is dependent on the columns field type

• null_bitmap (string.var_len) -- [len=(column_count + 8) / 7]

column_type_def

the column definitions. It is sent as length encoded string where the length of the string is the number of columns and each byte of it is the Protocol::ColumnType of the column.

column_meta_def

type-specific metadata for each column

Type	meta-len
Protocol::MYSQL_TYPE_STRING	2
Protocol::MYSQL_TYPE_VAR_STRING	2
Protocol::MYSQL_TYPE_VARCHAR	2
Protocol::MYSQL_TYPE_BLOB	1
Protocol::MYSQL_TYPE_DECIMAL	2
Protocol::MYSQL_TYPE_NEWDECIMAL	2
Protocol::MYSQL_TYPE_DOUBLE	1
Protocol::MYSQL_TYPE_FLOAT	1
Protocol::MYSQL_TYPE_ENUM	2
Protocol::MYSQL_TYPE_SET	see MYSQL_TYPE_ENUM
Protocol::MYSQL_TYPE_BIT	0
Protocol::MYSQL_TYPE_DATE	0
Protocol::MYSQL_TYPE_DATETIME	0
Protocol::MYSQL_TYPE_TIMESTAMP	0
Protocol::MYSQL_TYPE_TIME	--
Protocol::MYSQL_TYPE_TINY	0
Protocol::MYSQL_TYPE_SHORT	0
Protocol::MYSQL_TYPE_INT24	0
Protocol::MYSQL_TYPE_LONG	0
Protocol::MYSQL_TYPE_LONGLONG	0

Protocol::MYSQL_TYPE_STRING

due to Bug37426 layout of the string metadata is a bit tightly packed:

1              byte0
1              byte1

The two bytes encode type and length

NULL-bitmap

a bitmask contained a bit set for each column that can be NULL. The column-length is taken from the column-def