Please use the form below to provide your feedback. Because your feedback is valuable to us, the information you submit in this form is recorded in our issue tracking system (JIRA), which is publicly available. You can track the status of your feedback using the ticket number displayed in the dialog once you submit the form.

Manage and Monitor Queries

      +
      Monitoring and profiling SQL++ queries, query service nodes, and corresponding system resources is very important for smoother operational performance and efficiency of the system. In fact, often it is vital for diagnosing and troubleshooting issues such as query performance, resource bottlenecks, and overloading of various services.

      System keyspaces provide various monitoring details and statistics about individual queries and the Query service. When running on a cluster with multiple query nodes, stats about all queries on all query nodes are collected in the Query management and monitoring system keyspaces.

      For example, this can help identify:

      • The top 10 slow or fast queries running on a particular query node or the cluster.

      • Resource usage statistics of the query service, or resources used for a particular query.

      • Details about the active, completed, and prepared queries.

      • Find long running queries that are running for more than 2 minutes.

      These system keyspaces are transient in nature, and are not persisted to disk or permanent storage. Hence, the information in the keyspaces pertains to the current instantiation of the Query service.

      You can access the Query management and monitoring system keyspaces using any of the following:

      • SQL++ from the cbq shell or Query Workbench

      • The Query Admin REST API

      • A monitoring SDK

      Using SQL++ enables you to obtain further insights from the keyspaces.

      Authentication and Client Privileges

      Users must have the Query System Catalog role to access restricted system keyspaces. For more details about user roles, see Authorization.

      Examples on this Page

      In the REST API examples:

      • $BASE_URL is the protocol, host name or IP address, and port — for example, http://localhost:8093.

      • $USER is the user name.

      • $PASSWORD is the password.

      Monitor System Vitals

      The system:vitals catalog provides data about the running state and health of the query nodes, such as number of logical cores, active threads, queued threads, CPU utilization, memory usage, network utilization, garbage collection percentage, and so on. This information can be very useful to assess the current workload and performance characteristics of a query node.

      Get System Vitals

      To view system vitals, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To view system vitals with the Admin REST API:

      curl -u $USER:$PASSWORD $BASE_URL/admin/vitals

      To view system vitals with SQL++:

      SELECT * FROM system:vitals;

      System Vitals Details

      Getting system vitals, as described in Get System Vitals, returns results similar to the following.

      {
  "uptime": "7h39m32.668577197s",
  "local.time": "2021-04-30 18:42:39.517208807 +0000 UTC m=+27573.945319668",
  "version": "7.0.0-N1QL",
  "total.threads": 191,
  "cores": 2,
  "gc.num": 669810600,
  "gc.pause.time": "57.586373ms",
  "gc.pause.percent": 0,
  "memory.usage": 247985184,
  "memory.total": 11132383704,
  "memory.system": 495554808,
  "cpu.user.percent": 0,
  "cpu.sys.percent": 0,
  "request.completed.count": 140,
  "request.active.count": 0,
  "request.per.sec.1min": 0.0018,
  "request.per.sec.5min": 0.0055,
  "request.per.sec.15min": 0.0033,
  "request_time.mean": "536.348163ms",
  "request_time.median": "54.065567ms",
  "request_time.80percentile": "981.869933ms",
  "request_time.95percentile": "2.543128455s",
  "request_time.99percentile": "4.627922799s",
  "request.prepared.percent": 0
}

      For field names and meanings, see Vital Statistics.

      Monitor and Manage Active Requests

      The system:active_requests catalog lists all currently executing active requests or queries.

      Get Active Requests

      To view active requests, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To view active requests with the Admin REST API:

      curl -u $USER:$PASSWORD $BASE_URL/admin/active_requests

      To view active requests with SQL++:

      SELECT * FROM system:active_requests;

      To get the query plan for active requests, include meta().plan in a SQL++ query. See Query Profiling.

      • SQL++

      To view active requests with SQL++, including the query plan:

      SELECT *, meta().plan FROM system:active_requests;

      Terminate an Active Request

      To terminate an active request, for instance, a non-responding or a long-running query, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To terminate an active request uuid with the Admin REST API:

      curl -u $USER:$PASSWORD -X DELETE $BASE_URL/admin/active_requests/uuid

      To terminate an active request uuid with SQL++:

      DELETE FROM system:active_requests WHERE requestId = "uuid";

      Active Request Details

      Getting active requests, as described in Get Active Requests, returns results similar to the following.

      [
  {
    "active_requests": {
      "clientContextID": "832adfa0-e9e6-464e-b5e6-b7ec7549d511",
      "cpuTime": "111.877µs",
      "elapsedTime": "77.631814ms",
      "executionTime": "77.517185ms",
      "n1qlFeatCtrl": 76,
      "node": "127.0.0.1:8091",
      "phaseOperators": {
        "authorize": 1,
        "fetch": 1,
        "primaryScan": 1,
        "project": 1,
        "stream": 1
      },
      "phaseTimes": {
        "authorize": "4.998µs",
        "fetch": "69.519µs",
        "instantiate": "16.28µs",
        "parse": "597.435µs",
        "plan": "24.141851ms",
        "plan.index.metadata": "24.005473ms",
        "plan.keyspace.metadata": "2.022µs",
        "primaryScan": "23.496033ms",
        "project": "824ns",
        "stream": "2.242µs"
      },
      "queryContext": "default:travel-sample.inventory",
      "remoteAddr": "127.0.0.1:37506",
      "requestId": "05cc1895-9986-4819-b4d3-8a4311e8f319",
      "requestTime": "2024-05-21T13:29:16.864Z",
      "scanConsistency": "unbounded",
      "state": "running",
      "statement": "SELECT * FROM system:active_requests;",
      "statementType": "SELECT",
      "useCBO": true,
      "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:126.0) Gecko/20100101 Firefox/126.0",
      "users": "builtin:Administrator"
    }
  }
]

      For field names and meanings, see Requests.

      For query plan field names and meanings, see Query Profiling Details.

      Monitor and Manage Prepared Statements

      The system:prepareds catalog provides data about the known prepared statements and their state in a query node’s prepared statement cache. For each prepared statement, this catalog provides information such as name, statement, query plan, last use time, number of uses, and so on.

      A prepared statement is created and stored relative to the current query context. You can create multiple prepared statements with the same name, each stored relative to a different query context. This enables you to run multiple instances of the same application against different datasets.

      When there are multiple prepared statements with the same name in different query contexts, the name of the prepared statement in the system:prepareds catalog includes the associated query context in brackets.

      Get Prepared Statements

      To get a list of all known prepared statements, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To get a list of all known prepared statements with the Admin REST API:

      curl -u $USER:$PASSWORD $BASE_URL/admin/prepareds

      To get a list of all known prepared statements with a SQL++ query:

      SELECT * FROM system:prepareds;

      To get information about a specific prepared statement, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To get information about a specific prepared statement example1 with the Admin REST API:

      curl -u $USER:$PASSWORD $BASE_URL/admin/prepareds/example1

      To get information about a specific prepared statement example1 with a SQL++ query:

      SELECT * FROM system:prepareds WHERE name = "example1";

      To get the query plan for prepared statements, include meta().plan in a SQL++ query. See Query Profiling.

      • SQL++

      To view prepared statements with SQL++, including the query plan:

      SELECT *, meta().plan FROM system:prepareds;

      Delete Prepared Statements

      To delete a specific prepared statement, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To delete a prepared statement p1 with the Admin REST API:

      curl -u $USER:$PASSWORD -X DELETE $BASE_URL/admin/prepareds/p1

      To delete a prepared statement p1 with a SQL++ query:

      DELETE FROM system:prepareds WHERE name = "p1";

      To delete all the known prepared statements, use a SQL++ query.

      • SQL++

      To delete all known prepared statements:

      DELETE FROM system:prepareds;

      Prepared Statement Details

      To try the examples in this section, first create a couple of prepared statements.

      Create a prepared statement with default query context

      For this example, unset the query context. For more information, see Query Context.

      Query
      PREPARE p1 AS SELECT * FROM `travel-sample`.inventory.airline WHERE iata = "U2";
      Create a prepared statement with specified query context

      For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

      Query
      PREPARE p1 AS SELECT * FROM airline WHERE iata = "U2";

      Getting prepared statements, as described in Get Prepared Statements, returns results similar to the following.

      {
  "requestID": "d976e59a-d74e-4350-b0df-fa137099d594",
  "signature": {
    "*": "*",
    "plan": "json"
  },
  "results": [
    {
      "prepareds": {
        "encoded_plan": "H4sIAAAAAAAA/6RTUW/TPBT9K9H5XrbJ30QBMcmIhzJ1AjG0qh3wwKbEJLedmWt71061UIXfjpxkndYhENpbYt97z7nn+GxAtnQVVbk3ykICAgtSsWY6djayMwHy6JWAthXdjr3+TBy0s5Avh7N5qewHaoJXJQXIDSpaqNpEGVmtyfwf1MobOtR2TTY6bg6VZqMtQS6UCdQKWLUiSPgR+u9uFOTdIAg4T6yi4zT+v/sfjOt45Vj/IAh41mttaNmTONUhQn7d4FzxkuL9tL/SEpiyXkMepQ/nA+Sz9rIV+FleaVPtMpjTTU22TG19AZPtcP+5aMp6pbhJcr6AwLe6vO54P+CLQfR+n3zLPh/Y576fcleXe3bfqYydYxsMt/k1NZCR66T+9eAdJO4l+L0NoXQ+nWxhIVAHbZeQWAaNVjxc6YRiefWnXZ6EvYs2VayMIYMneXWiTSSGQOlspXvhsLdXDPyKw0KrqIr97E12gU/PL7D/iMh7q6NWZtpLDwGmUJuYR+JV6ADp1qfCQGaRVouKBzsu28s2vbYd4pFJrZDuBFJOtyE8Go0EbmriJqWVbmOfYKab86aTaz45nRyfJxC9tF2skyoHkDhAKzC0TGeT6Xg2yfwoG8+zvic7yE5mZx+z4oFpxePEZF/eTWaTLMmyFeV19zLo+O3ZsNivAAAA//+q+jhuaAQAAA==",
        "featuresControl": 76,
        "indexApiVersion": 4,
        "indexScanKeyspaces": {
          "default:travel-sample.inventory.airline": false
        },
        "name": "p1", (1)
        "namespace": "default",
        "node": "127.0.0.1:8091",
        "statement": "PREPARE p1 AS SELECT * FROM `travel-sample`.inventory.airline WHERE iata = \"U2\";",
        "uses": 0
      }
    },
    {
      "prepareds": {
        "encoded_plan": "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",
        "featuresControl": 76,
        "indexApiVersion": 4,
        "indexScanKeyspaces": {
          "default:travel-sample.inventory.airline": false
        },
        "name": "p1(travel-sample.inventory)", (2)
        "namespace": "default",
        "node": "127.0.0.1:8091",
        "statement": "PREPARE p1 AS SELECT * FROM airline WHERE iata = \"U2\";",
        "uses": 0
      }
    }
  ],
  "status": "success",
  "metrics": {
    "elapsedTime": "25.323496ms",
    "executionTime": "25.173646ms",
    "resultCount": 2,
    "resultSize": 7891,
    "serviceLoad": 12
  }
}

      In this example, the names of the prepared statements are identical, but they are associated with different query contexts.

      1 The name of the prepared statement for the default query context
      2 The name of the prepared statement showing the associated query context

      For field names and meanings, see Prepared Statements.

      For query plan field names and meanings, see Query Profiling Details.

      Monitor and Manage Completed Requests

      By default, the system:completed_requests catalog maintains a list of the most recent completed requests that have run longer than a predefined threshold of time. (You can also log completed requests that meet other conditions that you define.)

      For each completed request, this catalog maintains information such as requestId, statement text, prepared name (if prepared statement), request time, service time, and so on. This information provides a general insight into the health and performance of the query node and the cluster.

      Get Completed Requests

      To get a list of all logged completed requests, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To get a list of all logged completed requests using the Admin REST API:

      curl -u $USER:$PASSWORD $BASE_URL/admin/completed_requests

      To get a list of all logged completed requests using SQL++:

      SELECT * FROM system:completed_requests;

      Note that the completed state means that the request was started and completed by the Query service, but it does not mean that it was necessarily successful. The request could have been successful, or completed with errors.

      To find requests that completed successfully, search for completed requests whose state is completed and whose errorCount field has the value 0.

      • SQL++

      To get a list of all logged completed requests, including only successful requests:

      SELECT * FROM system:completed_requests
WHERE state = "completed" AND errorCount = 0;

      To get the query plan for completed requests, include meta().plan in a SQL++ query. See Query Profiling.

      • SQL++

      To view completed requests with SQL++, including the query plan:

      SELECT *, meta().plan FROM system:completed_requests;

      Purge the Completed Requests

      To purge a specific completed request, use the Admin REST API or a SQL++ query.

      • REST API

      • SQL++

      To purge a completed request uuid with the Admin REST API:

      curl -u $USER:$PASSWORD -X DELETE $BASE_URL/admin/completed_requests/uuid

      To purge a completed request uuid with SQL++:

      DELETE FROM system:completed_requests WHERE requestId = "uuid";

      To purge completed requests for a given time period, use a SQL++ query.

      • SQL++

      To purge the completed requests for a given time period:

      DELETE FROM system:completed_requests WHERE requestTime LIKE "2015-09-09%";

      Completed Request Details

      To try the examples in this section, first run a query which takes at least 1000ms (the default value of the completed-threshold query setting) to get registered in the system:completed_requests keyspace.

      Run a long query

      For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

      Query
      SELECT * FROM route ORDER BY sourceairport LIMIT 5;

      Getting completed requests, as described in Get Completed Requests, returns results similar to the following.

      [
  // ...
  {
    "completed_requests": {
      "clientContextID": "a19a61ab-cd9e-46c9-be71-92623ff85741",
      "cpuTime": "912.408423ms",
      "elapsedTime": "3.762926948s",
      "errorCount": 0,
      "errors": [],
      "n1qlFeatCtrl": 76,
      "node": "127.0.0.1:8091",
      "phaseCounts": {
        "fetch": 24023,
        "primaryScan": 24023,
        "primaryScan.GSI": 24023,
        "sort": 24028
      },
      "phaseOperators": {
        "authorize": 1,
        "fetch": 1,
        "primaryScan": 1,
        "primaryScan.GSI": 1,
        "project": 1,
        "sort": 2,
        "stream": 1
      },
      "phaseTimes": {
        "authorize": "15.111µs",
        "fetch": "3.641125449s",
        "instantiate": "332.963µs",
        "parse": "1.04015ms",
        "plan": "602.878µs",
        "plan.index.metadata": "25.849µs",
        "plan.keyspace.metadata": "11.586µs",
        "primaryScan": "101.118572ms",
        "primaryScan.GSI": "101.118572ms",
        "project": "33.273783ms",
        "run": "3.760767643s",
        "sort": "666.364325ms",
        "stream": "1.617688ms"
      },
      "queryContext": "default:travel-sample.inventory",
      "remoteAddr": "127.0.0.1:37684",
      "requestId": "e170bf67-d364-4ed7-9698-784bbb779d18",
      "requestTime": "2024-05-21T14:31:46.882Z",
      "resultCount": 5,
      "resultSize": 17714,
      "scanConsistency": "unbounded",
      "serviceTime": "3.762768429s",
      "state": "completed",
      "statement": "SELECT * FROM route ORDER BY sourceairport LIMIT 5;",
      "statementType": "SELECT",
      "useCBO": true,
      "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:126.0) Gecko/20100101 Firefox/126.0",
      "users": "builtin:Administrator",
      "~qualifier": "threshold"
    }
  }
]

      For field names and meanings, see Requests.

      For query plan field names and meanings, see Query Profiling Details.

      Configure Completed Requests

      You can configure the system:completed_requests keyspace by specifying parameters through the Admin REST API /admin/settings endpoint.

      You can specify the conditions for completed request logging using the completed field. This field takes a JSON object containing the names and values of logging qualifiers. Completed requests that meet the defined qualifiers are logged.

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed": {"user": "marco", "error": 12003}}'

      Logging Qualifiers

      You can specify the following logging qualifiers. A completed request is logged if any of the qualifiers are met (logical OR).

      threshold

      The execution time threshold in milliseconds.
      aborted

      Whether to log requests that generate a panic.
      error

      Log requests returning this error number.
      client

      Log requests from this IP address.
      user

      Log requests with this user name.
      context

      Log requests with this client context ID.

      For full details, see Logging Parameters.

      The basic syntax adds a qualifier to the logging parameters, i.e. any existing qualifiers are not removed. You can change the value of a logging qualifier by specifying the same qualifier again with a new value.

      To add a new instance of an existing qualifier, use a plus sign (+) before the qualifier name, e.g. +user. To remove a qualifier, use a minus sign (-) before the qualifier name, e.g. -user.

      For example, the following request will add user simon to those tracked, and remove error 12003.

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed": {"+user": "simon", "-error": 12003}}'

      Similarly, you could remove all logging by execution time with the following request, as long as the value matches the existing threshold.

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed": {"-threshold": 1000}}'

      Tagged Sets

      You can also specify qualifiers that have to be met as a group for the completed request to be logged (logical AND).

      To do this, specify the tag field along with a set of qualifiers, like so:

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed": {"user": "marco", "error": 12003, "tag": "both_user_and_error"}}'

      In this case, the request will be logged when both user and error match.

      The tag name can be any string that is meaningful and unique. Requests that match a tagged set of conditions are logged with a field ~tag, which is set to the name of the tag.

      To add a qualifier to a tagged set, specify the tag name again along with the new qualifier:

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed": {"client": "172.1.2.3", "tag": "both_user_and_error"}}'

      You cannot add a new instance of an existing qualifier to a tagged set using a plus sign (+) before the qualifier name. For example, you cannot add a user qualifier to a tagged set that already contains a user qualifier. If you need to track two users with the same error, create two tagged sets, one per user.

      You can remove a qualifier from a tagged set using a minus sign (-) before the qualifier name, e.g. -user. When you remove the last qualifier from a tagged set, the tagged set is removed.

      You can specify multiple tagged sets. In this case, completed requests are logged if they match all of the qualifiers in any of the tagged sets.

      You can also specify a mixture of tagged sets and individual qualifiers. In this case, completed requests are logged if they match any of the individual qualifiers, or all of the qualifiers in any of the tagged sets.

      Completed Threshold

      The completed-threshold field provides another way of specifying the threshold qualifier within the completed field.

      This field sets the minimum request duration after which requests are added to the system:completed_requests catalog. The default value is 1000ms. Specify 0 to log all requests and -1 to not log any requests to the keyspace.

      To specify a different value, use:

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed-threshold":0}'

      Completed Limit

      The completed-limit field sets the number of most recent requests to be tracked in the system:completed_requests catalog. The default value is 4000. Specify 0 to not track any requests and -1 to set no limit.

      To specify a different value, use:

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed-limit":1000}'

      Stream Completed Requests

      Couchbase Server 7.6.4

      In Couchbase Server 7.6.4 and later, you can stream completed requests to disk.

      To enable completed request streaming, use the Admin REST API /admin/settings endpoint to specify the completed_stream_size property.

      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"completed_stream_size":500}'

      This property is a file size in MiB. When set to 0 (the default), completed request streaming is disabled.

      When set to any size greater than 0, completed requests are streamed to archive files. The value of this property determines the size of the data to retain, per node. The configuration for completed requests determines which requests are saved.

      The additional processing required to save completed requests to disk may limit overall request throughput on a Query node, but typically only when every completed request is being recorded, and requests are very small or short-lived. The speed of the file system on which the server logs directory resides naturally affects the potential impact too.

      Archived Request Files

      When streaming is enabled, completed requests are saved to GZIP archives with the prefix local_request_log in the Couchbase Server logs directory. Each saved GZIP archive file contains multiple JSON entries, one for each for each recorded completed request.

      Couchbase Server writes multiple archive files in parallel, so whilst the order of requests in a file is sequential, a single given file may not contain a contiguous sequence of requests.

      When an archive file reaches or exceeds 100 MiB, it is finalized and saved to disk. This is not a hard limit — entries are not truncated to adhere to it. Files may also be finalized with less content, if nothing has been written to them for an extended period. Files that are actively being written are not available for reading, and they don’t count towards the configured size limit until they’re finalized.

      Couchbase Server tries to manage and retain archive files such that the total disk space used by the files is within the specified limit for the node. When the specified limit is reached, older files are removed as necessary to make space for newly finalized files. When a file is removed, it isn’t guaranteed that only the oldest requests are evicted, given that Couchbase Server writes to multiple archive files in parallel.

      View Archived Requests

      To view archived completed requests, use gzip and jq on the command line, or a SQL++ query.

      • Command Line

      • SQL++

      To view all archived completed requests in $FILE:

      gzip -qdc $FILE | jq .

      To get a list of archived completed requests using SQL++:

      SELECT * FROM system:completed_requests_history;

      The system:completed_requests_history keyspace is provided for SQL++ access to the archived files, but as they are external GZIP archives performance is restricted, particularly with large histories on clusters with multiple Query service nodes. Directly reading the files may be more useful in some cases.

      Query Profiling

      Query profiling enables you to obtain more detailed monitoring information and finer execution timings for any query. You can set query profiling to the following levels:

      • off — query profiling is disabled.

      • phases — query profiling is enabled, including information about the phases of query execution.

      • timings — query profiling is enabled, including information about the phases of query execution, and detailed timing information.

      You can set query profiling in the following ways:

      • At the node level, so that it is enabled for all queries on that node.

      • At the request level, for individual queries.

      For more information about Query settings and parameters, see Configure Queries.

      Enable Query Profiling for a Query Node

      To activate query profiling at the node level, specify the profile setting using the Admin REST API (/admin/settings endpoint).

      See the current node-level query settings

      The following request gets the current node-level query settings.

      Request
      curl $BASE_URL/admin/settings -u $USER:$PASSWORD
      Results
      {
  "atrcollection": "",
  "auto-prepare": false,
  "cleanupclientattempts": true,
  "cleanuplostattempts": true,
  "cleanupwindow": "1m0s",
  "completed": {
    "aborted": null,
    "threshold": 1000
  },
  "completed-limit": 4000,
  "completed-threshold": 1000,
  "controls": false,
  "cpuprofile": "",
  "debug": false,
  "functions-limit": 16384,
  "keep-alive-length": 16384,
  "loglevel": "INFO",
  "max-index-api": 4,
  "max-parallelism": 1,
  "memory-quota": 0,
  "memprofile": "",
  "mutexprofile": false,
  "n1ql-feat-ctrl": 76,
  "numatrs": 1024,
  "pipeline-batch": 16,
  "pipeline-cap": 512,
  "plus-servicers": 16,
  "prepared-limit": 16384,
  "pretty": false,
  "profile": "off",
  "request-size-cap": 67108864,
  "scan-cap": 512,
  "servicers": 4,
  "timeout": 0,
  "txtimeout": "0s",
  "use-cbo": true
}
      Save node-level query settings to a file

      The following request saves the current node-level query settings to the file query_settings.json.

      Request
      curl $BASE_URL/admin/settings -u $USER:$PASSWORD -o ./query_settings.json
      Set node-level query settings from a file

      Assuming that you have edited the file query_settings.json to specify the query settings you want, the following request sets the node-level query settings according to the file.

      Request
      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -X POST \
  -d@./query_settings.json
      Set node-level query settings explicitly

      The following request explicitly sets query profiling at the node level.

      Request
      curl $BASE_URL/admin/settings -u $USER:$PASSWORD \
  -H 'Content-Type: application/json' \
  -d '{"profile": "phases"}'
      Results
      {
  // ...
  "profile":"phases",
  "request-size-cap": 67108864,
  "scan-cap": 512,
  "servicers": 4,
  "timeout": 0,
  "txtimeout": "0s",
  "use-cbo": true
}

      Enable Query Profiling for a Request

      To activate profiling at the request level, you can:

      • Specify the profile setting using the Query REST API (/query/service endpoint).

      • Specify the profile setting using the cbq command line tool.

      • REST API

      • SQL++

      To set query settings using the REST API, specify the parameters in the request body.

      The following statement sets the profiling to phases:

      curl $BASE_URL/query/service -u $USER:$PASSWORD \
  -d 'profile=phases&statement=SELECT * FROM `travel-sample`.inventory.airline LIMIT 1'

      The following statement sets the profiling to timings:

      curl $BASE_URL/query/service -u $USER:$PASSWORD \
  -d 'profile=timings&statement=SELECT * FROM `travel-sample`.inventory.airline LIMIT 1'

      To set query settings using the cbq shell, use the \SET command.

      The following statement sets the profiling to phases:

      \set -profile "phases";
SELECT * FROM `travel-sample`.inventory.airline LIMIT 1;

      The following statement sets the profiling to timings:

      \set -profile "timings";
SELECT * FROM `travel-sample`.inventory.airline LIMIT 1;

      The Query Workbench automatically enables Query profiling, with detailed timing information. To disable or enable Query profiling with the Query Workbench, specify the Collect query timings option using the Query Preferences.

      Query Profiling Details

      You can access the profiling information in the following ways:

      When a query executes a user-defined function, profiling information is available for the SQL++ queries within the user-defined function as well.

      Profiling Details in Query Responses

      When profiling is enabled:

      • If you are using the cbq shell or the Query REST API, query profiling information is returned with the query results.

      • If you are using the Query workbench, query profiling information is not returned with the query results.

      Phases Profile

      If you are using the cbq shell or the Query REST API, the following statistics are returned when profile is set to phases:

      {
  "requestID": "06d6c1c2-1a8a-4989-a856-7314f9eddee5",
  "signature": {
    "*": "*"
  },
  "results": [
    {
      "airline": {
        "callsign": "MILE-AIR",
        "country": "United States",
        "iata": "Q5",
        "icao": "MLA",
        "id": 10,
        "name": "40-Mile Air",
        "type": "airline"
      }
    }
  ],
  "status": "success",
  "metrics": {
    "elapsedTime": "12.77927ms",
    "executionTime": "12.570648ms",
    "resultCount": 1,
    "resultSize": 254,
    "serviceLoad": 12
  },
  "profile": {
    "phaseTimes": {
      "authorize": "19.629µs",
      "fetch": "401.997µs",
      "instantiate": "147.686µs",
      "parse": "4.545234ms",
      "plan": "409.364µs",
      "primaryScan": "6.103775ms",
      "run": "6.699056ms"
    },
    "phaseCounts": {
      "fetch": 1,
      "primaryScan": 1
    },
    "phaseOperators": {
      "authorize": 1,
      "fetch": 1,
      "primaryScan": 1
    },
    "requestTime": "2021-04-30T18:37:56.394Z",
    "servicingHost": "127.0.0.1:8091"
  }
}
      Timings Profile

      If you are using the cbq shell or the Query REST API, the following statistics are returned when profile is set to timings:

      {
  "requestID": "268a1240-6864-43a2-af13-ccb8d1e50abf",
  "signature": {
    "*": "*"
  },
  "results": [
    {
      "airline": {
        "callsign": "MILE-AIR",
        "country": "United States",
        "iata": "Q5",
        "icao": "MLA",
        "id": 10,
        "name": "40-Mile Air",
        "type": "airline"
      }
    }
  ],
  "status": "success",
  "metrics": {
    "elapsedTime": "2.915245ms",
    "executionTime": "2.755355ms",
    "resultCount": 1,
    "resultSize": 254,
    "serviceLoad": 12
  },
  "profile": {
    "phaseTimes": {
      "authorize": "18.096µs",
      "fetch": "388.122µs",
      "instantiate": "31.702µs",
      "parse": "646.157µs",
      "plan": "120.427µs",
      "primaryScan": "1.402918ms",
      "run": "1.936852ms"
    },
    "phaseCounts": {
      "fetch": 1,
      "primaryScan": 1
    },
    "phaseOperators": {
      "authorize": 1,
      "fetch": 1,
      "primaryScan": 1
    },
    "requestTime": "2021-04-30T18:40:13.239Z",
    "servicingHost": "127.0.0.1:8091",
    "executionTimings": {
      "#operator": "Authorize",
      "#stats": {
        "#phaseSwitches": 4,
        "execTime": "1.084µs",
        "servTime": "17.012µs"
      },
      "privileges": {
        "List": [
          {
            "Target": "default:travel-sample.inventory.airline",
            "Priv": 7,
            "Props": 0
          }
        ]
      },
      "~child": {
        "#operator": "Sequence",
        "#stats": {
          "#phaseSwitches": 1,
          "execTime": "2.474µs"
        },
        "~children": [
          {
            "#operator": "PrimaryScan3",
            "#stats": {
              "#itemsOut": 1,
              "#phaseSwitches": 7,
              "execTime": "18.584µs",
              "kernTime": "8.869µs",
              "servTime": "1.384334ms"
            },
            "bucket": "travel-sample",
            "index": "def_inventory_airline_primary",
            "index_projection": {
              "primary_key": true
            },
            "keyspace": "airline",
            "limit": "1",
            "namespace": "default",
            "scope": "inventory",
            "using": "gsi"
          },
          {
            "#operator": "Fetch",
            "#stats": {
              "#itemsIn": 1,
              "#itemsOut": 1,
              "#phaseSwitches": 10,
              "execTime": "25.64µs",
              "kernTime": "1.427752ms",
              "servTime": "362.482µs"
            },
            "bucket": "travel-sample",
            "keyspace": "airline",
            "namespace": "default",
            "scope": "inventory"
          },
          {
            "#operator": "InitialProject",
            "#stats": {
              "#itemsIn": 1,
              "#itemsOut": 1,
              "#phaseSwitches": 9,
              "execTime": "6.006µs",
              "kernTime": "1.825917ms"
            },
            "result_terms": [
              {
                "expr": "self",
                "star": true
              }
            ]
          },
          {
            "#operator": "Limit",
            "#stats": {
              "#itemsIn": 1,
              "#itemsOut": 1,
              "#phaseSwitches": 4,
              "execTime": "2.409µs",
              "kernTime": "2.094µs"
            },
            "expr": "1"
          },
          {
            "#operator": "Stream",
            "#stats": {
              "#itemsIn": 1,
              "#itemsOut": 1,
              "#phaseSwitches": 6,
              "execTime": "46.964µs",
              "kernTime": "1.844828ms"
            }
          }
        ]
      },
      "~versions": [
        "7.0.0-N1QL",
        "7.0.0-4960-enterprise"
      ]
    }
  }
}

      For field names and meanings, see Profile.

      Profiling Details in System Catalogs

      The system:active_requests and system:completed_requests system catalogs always return profiling information regarding query phases: that is, phase times, phase counts, and phase operators.

      The system:active_requests, system:completed_requests, and system:prepareds system catalogs also support the meta().plan virtual attribute. This captures the whole query plan, and includes profiling information regarding execution timings.

      To get execution timing information from these system catalogs, you must explicitly specify meta().plan in the projection list for the SELECT query.

      Within these system catalogs, not all statements have a meta().plan attribute.

      When request profiling is set to timings, profiling information is likely to use 100KB+ per entry in the system:completed_requests keyspace.

      • Due to the added overhead of running both profiling and logging, turn on both of them only when needed. Running only one of them continuously has no noticeable affect on performance.

      • Profiling does not carry any extra cost beyond memory for completed requests, so it’s fine to run it continuously.
      Plan Details

      Getting the plan for a statement that you ran when the profile was set to timings returns results similar to the following.

      [
  {
  // ...
    "plan": {
      "#operator": "Authorize",
      "#stats": {
        "#phaseSwitches": 4,
        "execTime": "1.725µs",
        "servTime": "21.312µs"
      },
      "privileges": {
        "List": [
          {
            "Priv": 7,
            "Props": 0,
            "Target": "default:travel-sample.inventory.route"
          }
        ]
      },
      "~child": {
        "#operator": "Sequence",
        "#stats": {
          "#phaseSwitches": 2,
          "execTime": "1.499µs"
        },
        "~children": [
          {
            "#operator": "PrimaryScan3",
            "#stats": {
              "#heartbeatYields": 6,
              "#itemsOut": 24024,
              "#phaseSwitches": 96099,
              "execTime": "84.366121ms",
              "kernTime": "3.021901421s",
              "servTime": "69.320752ms"
            },
            "bucket": "travel-sample",
            "index": "def_inventory_route_primary",
            "index_projection": {
              "primary_key": true
            },
            "keyspace": "route",
            "namespace": "default",
            "scope": "inventory",
            "using": "gsi"
          },
          {
            "#operator": "Fetch",
            "#stats": {
              "#heartbeatYields": 7258,
              "#itemsIn": 24024,
              "#itemsOut": 24024,
              "#phaseSwitches": 99104,
              "execTime": "70.34694ms",
              "kernTime": "142.630196ms",
              "servTime": "3.021959695s"
            },
            "bucket": "travel-sample",
            "keyspace": "route",
            "namespace": "default",
            "scope": "inventory"
          },
          {
            "#operator": "InitialProject",
            "#stats": {
              "#itemsIn": 24024,
              "#itemsOut": 24024,
              "#phaseSwitches": 96100,
              "execTime": "15.331951ms",
              "kernTime": "3.219612458s"
            },
            "result_terms": [
              {
                "expr": "self",
                "star": true
              }
            ]
          },
          {
            "#operator": "Order",
            "#stats": {
              "#itemsIn": 24024,
              "#itemsOut": 24024,
              "#phaseSwitches": 72078,
              "execTime": "147.889352ms",
              "kernTime": "3.229055752s"
            },
            "sort_terms": [
              {
                "expr": "(`route`.`sourceairport`)"
              }
            ]
          },
          {
            "#operator": "Stream",
            "#stats": {
              "#itemsIn": 24024,
              "#itemsOut": 24024,
              "#phaseSwitches": 24025,
              "execTime": "11.851634134s"
            }
          }
        ]
      },
      "~versions": [
        "7.0.0-N1QL",
        "7.0.0-4960-enterprise"
      ]
    }
  }
]

      For field names and meanings, see Execution Timings.

      Query Profiling Summary

      The following table summarizes Query profiling behavior.

      Profile is …​ Query returns …​ Catalog includes …​

      cbq

      REST API

      Query
      workbench

      Active
      Requests

      Completed
      Requests

      Prepared
      Statements

      off

      phases

      phases

      timings

      phases

      phases

      phases

      phases

      phases

      timings

      timings

      phases
      timings

      phases
      timings

      phases
      timings

      phases
      timings

      timings