ROWS_EVENT_V1/V2, ROWS_COMPRESSED_EVENT_V1

A ROWS_EVENT_V1 is written for row based replication if data is inserted, deleted or updated

A ROWS_EVENT (version 2) is written for row based replication if data is inserted, deleted or updated if database server is MySQL 5.6 or newer. MariaDB Server doesn't send version 2 row events.

Event types

WRITE_ROWS_EVENT_V1	Insert new row
UPDATE_ROWS_EVENT_V1	Update existing row
DELETE_ROWS_EVENT_V1	Delete existing row
WRITE_ROWS_COMPRESSED_EVENT_V1	Insert new row
UPDATE_ROWS_COMPRESSED_EVENT_V1	Update existing row
DELETE_ROWS_COMPRESSED_EVENT_V1	Delete existing row
WRITE_ROWS_EVENT	Insert new row (version 2, MySQL only)
UPDATE_ROWS_EVENT	Update existing row (version 2, MySQL only)
DELETE_ROWS_EVENT	Delete existing row (version 2, MySQL only)

Header

• WRITE_ROWS_EVENT_V1: Event Type is 23 (0x17)

• UPDATE_ROWS_EVENT_V1: Event Type is 24 (0x18)

• DELETE_ROWS_EVENT_V1: Event Type is 25 (0x19)

• WRITE_ROWS_EVENT: Event Type is 30 (0xFD)

• UPDATE_ROWS_EVENT: Event Type is 31 (0xFE)

• DELETE_ROWS_EVENT: Event Type is 32 (0x20)

• WRITE_ROWS_COMPRESSED_EVENT_V1: Event Type is 166 (0xA6)

• UPDATE_ROWS_COMPRESSED_EVENT_V1: Event Type is 167 (0xA7)

• DELETE_ROWS_COMPRESSED_EVENT_V1: Event Type is 168 (0xA8)

Fields

• uint<6> The table id

• uint<2> Flags

• if rows_event is version 2

  • uint<2> Extra data length

  • string Extra data

• uint Number of columns

• byteColumns used. n = (number_of_columns + 7)/8

• if (event_type == UPDATE_ROWS_EVENT_v1

  • byte Columns used (Update). n = (number_of_columns + 7)/8

• if *_COMPRESSED_EVENT_V1

  • byte<1> header

    • algorithm: (header & 0x07) >> 4 (always 0=zlib)

    • header_size: header & 0x07

  • byte<header_size>uncompressed length, stored in MyISAM format:

• byte Null Bitmap (n = (number_of_columns + 7)/8)

• string Column data. The length needs to be calculated by checking the column types from referring TABLE_MAP_EVENT.

• if (event_type == UPDATE_ROWS_EVENT_v1

  • byte Null Bitmap_Update. n = (number_of_columns + 7)/8

  • string Update Column data. The length needs to be calculated by checking the used colums bitmap and column types from referring TABLE_MAP_EVENT.

Table id

Table id refers to a table defined by TABLE_MAP_EVENT. The special value 0xFFFFFF should have "end of statement flag" (0x0001) set and indicates that table maps can be freed.

Flags

0x0001	End of statement
0x0002	No foreign key checks
0x0004	No unique key checks
0x0008	Indicates that rows in this event are complete
0x0010	No check constraints

Extra data length (version 2)

The length of extra data

Extra data (version 2)

Extra data, length is extra data length - 2

Column Data Formats

The row data is stored in a packed format where each field is encoded in a particular format. The encoding is almost identical to the binary protocol but there are a few differences.

The field metadata is stored in the metadata block of the TABLE_MAP_EVENT. The metadata is required to decode the events. The following list shows number of bytes a field uses from the metadata block.

• 2 bytes

  • MYSQL_TYPE_BIT

  • MYSQL_TYPE_ENUM

  • MYSQL_TYPE_SET

  • MYSQL_TYPE_NEWDECIMAL

  • MYSQL_TYPE_DECIMAL

  • MYSQL_TYPE_VARCHAR

  • MYSQL_TYPE_VAR_STRING

  • MYSQL_TYPE_STRING

• 1 byte

  • MYSQL_TYPE_TINY_BLOB

  • MYSQL_TYPE_MEDIUM_BLOB

  • MYSQL_TYPE_LONG_BLOB

  • MYSQL_TYPE_BLOB

  • MYSQL_TYPE_TIMESTAMP2

  • MYSQL_TYPE_DATETIME2

  • MYSQL_TYPE_TIME2

  • MYSQL_TYPE_FLOAT

  • MYSQL_TYPE_DOUBLE

The types that aren't listed here do not store data in the the metadata block.

Simple Types

MYSQL_TYPE_NULL	Bit set in null bitmap, no value in row data
MYSQL_TYPE_TINY	1 byte integer
MYSQL_TYPE_YEAR	1 byte integer (year = value + 1900)
MYSQL_TYPE_SHORT	2 byte integer
MYSQL_TYPE_INT24	3 byte integer
MYSQL_TYPE_LONG	4 byte integer
MYSQL_TYPE_LONGLONG	8 byte integer
MYSQL_TYPE_FLOAT	4 byte floating point value (stored as a C float type)
MYSQL_TYPE_DOUBLE	8 byte floating point value (stored as a C double type)

MYSQL_TYPE_BLOB and other blob types

Stored as a length-encoded string where the string is preceded by a variable-sized integer that stores the length of the blob. The size of the preceding integer in bytes is stored as a one byte integer in the table metadata that is a part of the table map event.

For example if the value 4 is stored in the table metadata the length is stored as a 4 byte integer (e.g. uint32_t) followed by the data.

The exact column_type can be determined by the metadata length:

Length	Type
1	MYSQL_TYPE_TINY_BLOB
2	MYSQL_TYPE_BLOB
3	MYSQL_TYPE_MEDIUM_BLOB
4	MYSQL_TYPE_LONG_BLOB

MYSQL_TYPE_STRING, MYSQL_TYPE_SET and MYSQL_TYPE_ENUM

Stored as a fixed-length string with the length of the string stored in the second byte of the table metadata. All three of these types are stored as MYSQL_TYPE_STRING in the binlog and the real type of the field is stored in the first byte of the metadata.

MYSQL_TYPE_VARCHAR and other variable length string types

Stored as a length-encoded string where the string is preceded by a variable-sized integer that stores the length of the string. The field length is stored as a two byte integer in the table metadata.

If the field length is larger than 255, the string length is stored as a two byte integer. If the value is equal to or less than 255, the string length is stored as a one byte integer.

MYSQL_TYPE_DATETIME

Note: This field type is only used in MariaDB if global variable mysql56_temporal_format was set to OFF. Stored as a 8 byte value with the values stored as multiples of 100. This means that the stored value is in the format YYYYMMDDHHMMSS and can be easily extracted by repeatedly calculating the remainder of dividing the value by 100 and dividing the value by 100. The following pseudo-code demonstrates extracting the value.

value = read_8_byte_value(row_data)
date_val= value / 1000000
time_val= value % 1000000

year = (date_val / 100) / 100
month = (date_val / 100) % 100
day = date_val % 100
hour= (time_val / 100) / 100
minute = (time_val / 100) % 100
second = time_val % 100

MYSQL_TYPE_TIME

Note: This field type is only used in MariaDB if global variable mysql56_temporal_format was set to OFF. Stored as a 3 byte value with the values stored as multiples of 100. This means that the stored value is in the format HHMMSS and can be easily extracted the same way a MYSQL_TYPE_DATETIME is extracted. The following pseudo-code demonstrates extracting the value.

time_val = read_3_byte_value(row_data); /* myisam pack format */
hour= (time_val / 100) / 100;
minute = (time_val / 100) % 100;
second = time_val % 100;

MYSQL_TYPE_DATETIME2

Stored as 4-byte value The number of decimals for the fractional part is stored in the table metadata as a one byte value. The number of bytes that follow the 5 byte datetime value can be calculated with the following formula: (decimals + 1) / 2

val = read_5_byte_value(row_data) - 0x8000000000
d_val= val >> 17;
t_val = val % (1 << 17);

day= d_val % (1 << 5);
month= (d_val >> 5) % 13;
year= (d_val >> 5) / 13;
second= t_val % (1 << 6);
minute= (t_val >> 6) % (1 << 6);
hour= (t_val)(time_part >> 12);

MYSQL_TYPE_TIME2

Stored as 3-byte value The number of decimals for the fractional part is stored in the table metadata as a one byte value. The number of bytes that follow the 3 byte time value can be calculated with the following formula: (decimals + 1) / 2

t_val = read_3_byte_value(row_data) - 0x800000
if (t_val < 0)
{
  signed= 1;
  t_val= - tval;
}
hour= (t_val >> 12) % (1 << 10);
minute= (t_val >> 6) % (1 << 6);
second= t_val % (1 << 6);

MYSQL_TYPE_TIMESTAMP2

Stored as a 4 byte UNIX timestamp (number of seconds since 00:00, Jan 1 1970 UTC) followed by the fractional second parts. The number of decimals for the fractional part is stored in the table metadata as a one byte value. The number of bytes that follow the 4 byte timestamp can be calculated with the following formula: (decimals + 1) / 2

Microseconds for MYSQL_TYPE_DATETIME2, MYSQL_TYPE_TIME2 and MYSQL_TYPE_TIMESTAMP

len = (decimals + 1) / 2
  val= read_len_byte_value(row_data)
  llen= 0: microseconds= 0
  len = 1 or 2: microseconds = val * 10000
  len = 3 or 4: microseconds = 2-bytes val in myisam pack format
  len = 5 or 6: microseconds = 3-bytes val in myisam pack format

MYSQL_TYPE_DATE

Stored as a 3 byte value where bits 1 to 5 store the day, bits 6 to 9 store the month and the remaining bits store the year.

MYSQL_TYPE_TIMESTAMP

Stored as a 4 byte UNIX timestamp (number of seconds since 00:00, Jan 1 1970 UTC).

Example From mysqlbinlog Utility, CRC32

# at 1680
#180611  9:50:51 server id 1  end_log_pos 1754 CRC32 0x5415a8fb 	Write_rows: table id 23 flags: STMT_END_F

BINLOG '
2ykeWxMBAAAAPgAAAJAGAAAAABcAAAAAAAEABHRlc3QACWJ1bGtfbnVsbAAFDwMFE/YGFAAIAAMB
H1bULg8=
2ykeWxcBAAAASgAAANoGAAAAABcAAAAAAAEABf/gATMDAAAAAAAAAAAACECAAACDAP/gATMDAAAA
AAAAAAAACECAAACDAPuoFVQ=
'/*!*/;

Example Event As It's Written In The Binlog File

db 29 1e 5b 17 01 00 00 00 4a 00       .).[.....J.
00 00 da 06 00 00 00 00 17 00 00 00 00 00 01 00  ................
05 ff e0 01 33 03 00 00 00 00 00 00 00 00 00 08  ....3...........
40 80 00 00 83 00 ff e0 01 33 03 00 00 00 00 00  @........3......
00 00 00 00 08 40 80 00 00 83 00 fb a8 15 54     .....@........T                                   ....

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