I'm using pt-query-digest to analyze mysql binlog. Unfortunately, I can't find any description in pt-query-digest documentation about "Query size" row in the report. I guess, that this characteristics related with query output size, but it's an UPDATE statement, not SELECT.
# Query 2: 235.21 QPS, 52.92x concurrency, ID 0x7ABED476DE0F9BF3 at byte 652451215
# This item is included in the report because it matches --limit.
# Scores: V/M = 29.85
# Time range: 2017-03-30 15:56:22 to 16:30:19
# Attribute pct total min max avg 95% stddev median
# ============ === ======= ======= ======= ======= ======= ======= =======
# Count 9 479132
# Exec time 45 107792s 0 51s 225ms 0 3s 0
# Query size 28 127.99M 266 283 280.11 271.23 2.44 271.23
# error code 0 0 0 0 0 0 0 0
# String:
# Databases dbname
# Query_time distribution
# 1us
# 10us
# 100us
# 1ms
# 10ms
# 100ms
# 1s #################################
# 10s+ ################################################################
# Tables
# SHOW TABLE STATUS FROM `dbname` LIKE 'tblname'\G
# SHOW CREATE TABLE `dbname`.`tblname`\G
UPDATE `tblname`
SET `field1` = 100,
`time` = NOW()
WHERE `field2` = 1
AND `field3` = 2
AND `field4` = 3
AND `field5` = 0
What's the purpose of it?
Query size ... is the byte size of your query
In your case its the byte size of the string
"UPDATE `tblname`
SET `field1` = 100,
`time` = NOW()
WHERE `field2` = 1
AND `field3` = 2
AND `field4` = 3
AND `field5` = 0"