Why does each request have two times? what does it mean?

as shown in the figure, there are two times for each request, the last column? Who can explain?


above is the total time from the request to the last byte received by Time, and below is the time from the start of the request to the first byte received by Latency,.

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b30598-40d4b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b30598-40d4b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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