USER_VAR_EVENT

The USER_VAR_EVENT logs the value of a user-defined variable, ensuring that statements using variables replicate consistently.

A USER_VAR_EVENT is written every time a statement uses a user defined variable.

Header

• Event Type is 14 (0x0e).

Fields

• uint<4> The length of the user variable name.

• string The name of the user variable.

• uint<1> NULL indicator.

• If (not null indicator):

  • uint<1> variable type.

  • uint<4> collation number.

  • uint<4> The length of value.

  • string value.

  • uint<1> flags.

Variable type

Value	Type	Example
0x00	STRING_RESULT	set @a:="foo"
0x01	REAL_RESULT	set @a:= @@timestamp
0x02	INT_RESULT	set @a:= 4
0x03	ROW_RESULT	(not in use)
0x04	DECIMAL_RESULT	set @a:=1.2345

Flag

0x01	unsigned

Example for SET @foo:="bar" From mysqlbinlog Utility, CRC32

# at 511
#180610 10:26:43 server id 1  end_log_pos 554 CRC32 0x7dd93d6b 	User_var
SET @`foo`:=_utf8 X'626172' COLLATE `utf8_general_ci`/*!*/;

Example Event as Written to the Binlog File

c3 e0 1c 5b 0e 01 00 00 00 2b 00       ...[.....+.
00 00 2a 02 00 00 00 00 03 00 00 00 66 6f 6f 00  ..*.........foo.
00 21 00 00 00 03 00 00 00 62 61 72 6b 3d d9 7d  .!.......bark=.}                                          ....

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