10.4. Queue Configuration
The queueing rules are defined in a JSON file and control the number of queries
that can be submitted to Presto and the quota of running queries per queue.
The filename of the JSON config file should be specified in query.queue-config-file
config property.
Rules that specify multiple queues will cause the query to acquire the queues’ permits sequentially. The query must acquire all queues’ permits before it starts being executed. It acquires the next queue permit only after it is accepted for execution by the previous queue. A slot for the query is reserved in all queues. The query is rejected if no slot is available in any of the queues.
Rules are processed sequentially and the first one that matches will be used.
In the example configuration below, there are five queue templates.
In the user.${USER}
queue, ${USER}
will be expanded to the name of the
user that submitted the query. ${SOURCE}
is also supported, which expands
to the source submitting the query. The source name can be set as follows:
- CLI: use the
--source
option.- JDBC: set the
ApplicationName
client info property on theConnection
instance.
Example
There are three rules that define which queries go into which queues:
- The first rule makes
bob
an admin.- The second rule states that all queries that come from a source that includes
pipeline
should first be queued in the user’s personal pipeline queue, then thepipeline
queue. When a query acquires a permit from a new queue, it doesn’t release permits from previous queues until the query finishes execution.- The last rule is a catch all, which puts all queries into the user’s personal queue.
All together these rules implement the policy that bob
is an admin and
all other users are subject to the follow limits:
- Users are allowed to have up to 5 queries running. Additionally, they may run one pipeline.
- No more than 10
pipeline
queries may run at once.- No more than 100 other queries may run at once.
{
"queues": {
"user.${USER}": {
"maxConcurrent": 5,
"maxQueued": 20
},
"user_pipeline.${USER}": {
"maxConcurrent": 1,
"maxQueued": 10
},
"pipeline": {
"maxConcurrent": 10,
"maxQueued": 100
},
"admin": {
"maxConcurrent": 100,
"maxQueued": 100
},
"global": {
"maxConcurrent": 100,
"maxQueued": 1000
}
},
"rules": [
{
"user": "bob",
"queues": ["admin"]
},
{
"source": ".*pipeline.*",
"queues": [
"user_pipeline.${USER}",
"pipeline",
"global"
]
},
{
"queues": [
"user.${USER}",
"global"
]
}
]
}