We’re overhauling Dgraph’s docs to make them clearer and more approachable. If you notice any issues during this transition or have suggestions, please let us know.
The dgraph increment tool increments a counter value via transactions. The increment tool can be used as a health check that an Alpha is able to service transactions for both queries and mutations.

​
Example

Increment the default predicate (counter.val) once. If the predicate doesn’t yet exist, then it is created starting at counter 0. 
dgraph increment
Increment the counter predicate against the Alpha running at address --alpha (default: localhost:9080): 
dgraph increment --alpha=192.168.1.10:9080
Increment the counter predicate specified by --pred (default: counter.val): 
dgraph increment --pred=counter.val.healthcheck
Run a read-only query for the counter predicate and doesn’t run a mutation to increment it: 
dgraph increment --ro
Run a best-effort query for the counter predicate and doesn’t run a mutation to increment it: 
dgraph increment --be
Run the increment tool 1000 times every 1 second: 
dgraph increment --num=1000 --wait=1s

​
Increment tool output

 Run increment a few times
$ dgraph increment
0410 10:31:16.379 Counter VAL: 1   [ Ts: 1 ]
$ dgraph increment
0410 10:34:53.017 Counter VAL: 2   [ Ts: 3 ]
$ dgraph increment
0410 10:34:53.648 Counter VAL: 3   [ Ts: 5 ]

 Run read-only queries to read the counter a few times
$ dgraph increment --ro
0410 10:34:57.35  Counter VAL: 3   [ Ts: 7 ]
$ dgraph increment --ro
0410 10:34:57.886 Counter VAL: 3   [ Ts: 7 ]
$ dgraph increment --ro
0410 10:34:58.129 Counter VAL: 3   [ Ts: 7 ]

 Run best-effort query to read the counter a few times
$ dgraph increment --be
0410 10:34:59.867 Counter VAL: 3   [ Ts: 7 ]
$ dgraph increment --be
0410 10:35:01.322 Counter VAL: 3   [ Ts: 7 ]
$ dgraph increment --be
0410 10:35:02.674 Counter VAL: 3   [ Ts: 7 ]

 Run a read-only query to read the counter 5 times
$ dgraph increment --ro --num=5
0410 10:35:18.812 Counter VAL: 3   [ Ts: 7 ]
0410 10:35:18.813 Counter VAL: 3   [ Ts: 7 ]
0410 10:35:18.815 Counter VAL: 3   [ Ts: 7 ]
0410 10:35:18.817 Counter VAL: 3   [ Ts: 7 ]
0410 10:35:18.818 Counter VAL: 3   [ Ts: 7 ]

 Increment the counter 5 times
$ dgraph increment --num=5
0410 10:35:24.028 Counter VAL: 4   [ Ts: 8 ]
0410 10:35:24.061 Counter VAL: 5   [ Ts: 10 ]
0410 10:35:24.104 Counter VAL: 6   [ Ts: 12 ]
0410 10:35:24.145 Counter VAL: 7   [ Ts: 14 ]
0410 10:35:24.178 Counter VAL: 8   [ Ts: 16 ]

 Increment the counter 5 times, once every second.
$ dgraph increment --num=5 --wait=1s
0410 10:35:26.95  Counter VAL: 9   [ Ts: 18 ]
0410 10:35:27.975 Counter VAL: 10   [ Ts: 20 ]
0410 10:35:28.999 Counter VAL: 11   [ Ts: 22 ]
0410 10:35:30.028 Counter VAL: 12   [ Ts: 24 ]
0410 10:35:31.054 Counter VAL: 13   [ Ts: 26 ]

 If the Alpha is too busy or unhealthy, the tool will timeout and retry.
$ dgraph increment
0410 10:36:50.857 While trying to process counter: Query error: rpc error: code = DeadlineExceeded desc = context deadline exceeded. Retrying...