ROWS_EVENT_V1
A ROWS_EVENT_V1 is written for row based replication if data is inserted, deleted or updated:
Event types
WRITE_ROWS_EVENT_V1 | Insert new row |
UPDATE_ROWS_EVENT_V1 | Update existing row |
DELETE_ROWS_EVENT_V1 | Delete existing row |
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)
Fields
- uint<6> The table id
- uint<2> Flags
- uint<lenenc> Number of columns
- byte<n>Columns used. n = (number_of_columns + 7)/8
- if (event_type == UPDATE_ROWS_EVENT_v1
- byte<n> Columns used (Update). n = (number_of_columns + 7)/8
- byte<n> Null Bitmap (n = (number_of_columns + 7)/8)
- string<len> 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<n> Null Bitmap_Update. n = (number_of_columns + 7)/8
- string<len> Update Column data. The length needs to be calculated by checking the used colums bitmap and column types from referring TABLE_MAP_EVENT.
Flags
0x0001 | End of statement |
0x0002 | No foreign key checks |
0x0004 | No unique key checks |
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.
Simple Types
MYSQL_TYPE_NULL | Bit set in null bitmap, no value in row data |
MYSQL_TYPE_TINY | 1 byte integer |
MYSQL_TYPE_SHORT | 2 byte integer |
MYSQL_TYPE_YEAR | 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.
MYSQL_TYPE_VARCHAR
and other 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
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) seconds = value % 100 value = value / 100 minutes = value % 100 value = value / 100 hours = value % 100 value = value / 100 days = value % 100 value = value / 100 months = value % 100 value = value / 100 years = value
MYSQL_TYPE_TIME
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.
value = read_3_byte_value(row_data) seconds = value % 100 value = value / 100 minutes = value % 100 value = value / 100 hours = value
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).
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
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 ....