Last spring, we added a feature that allows the user to see the progress of writes in a statement. Vadim liked it. In 2.2.0, in “show processlist”, we add progress information on reads.

Here is an example of what “show processlist” displays on an update:

mysql> show processlist G
*************************** 1. row ***************************
Id: 1
User: root
Host: localhost
db: test
Command: Query
Time: 7
State: Queried about 1576008 rows, Updated about 197000 rows
Info: update foo set a=9 where a=8

Here is an example of what “show processlist” displays on an insert that requires a query:

mysql> show processlist G
*************************** 1. row ***************************
Id: 1
User: root
Host: localhost
db: test
Command: Query
Time: 6
State: Queried about 1542001 rows, Inserted about 771000 rows
Info: insert into bar select* from foo where a < 5

And here is an example of what show processlist displays in a query:

mysql> show processlist G
*************************** 1. row ***************************
Id: 1
User: root
Host: localhost
db: test
Command: Query
Time: 4
State: Queried about 2790000 rows
Info: select sum(a) from foo

As we see in the examples above, the work required to execute some statements are a combination of reads and writes. Having progress information on both helps provide the user with a better understanding of what is going on in the system.