Metricbeat metricset for postgresql/bgwriter (#2319)

Part of #2255.

metricbeat/docs/fields.asciidoc

@@ -1512,6 +1512,101 @@ Current overall state of this backend. Possible values are:
 Text of this backend's most recent query. If state is active this field shows the currently executing query. In all other states, it shows the last query that was executed.
 
 
+[float]
+== bgwriter Fields
+
+Statistics about the background writer process's activity. Collected using the pg_stat_bgwriter query.
+
+
+
+[float]
+=== postgresql.bgwriter.checkpoints.scheduled
+
+type: long
+
+Number of scheduled checkpoints that have been performed.
+
+
+[float]
+=== postgresql.bgwriter.checkpoints.requested
+
+type: long
+
+Number of requested checkpoints that have been performed.
+
+
+[float]
+=== postgresql.bgwriter.checkpoints.times.write.ms
+
+type: float
+
+Total amount of time that has been spent in the portion of checkpoint processing where files are written to disk, in milliseconds.
+
+
+[float]
+=== postgresql.bgwriter.checkpoints.times.sync.ms
+
+type: float
+
+Total amount of time that has been spent in the portion of checkpoint processing where files are synchronized to disk, in milliseconds.
+
+
+[float]
+=== postgresql.bgwriter.buffers.checkpoints
+
+type: long
+
+Number of buffers written during checkpoints.
+
+
+[float]
+=== postgresql.bgwriter.buffers.clean
+
+type: long
+
+Number of buffers written by the background writer.
+
+
+[float]
+=== postgresql.bgwriter.buffers.clean_full
+
+type: long
+
+Number of times the background writer stopped a cleaning scan because it had written too many buffers.
+
+
+[float]
+=== postgresql.bgwriter.buffers.backend
+
+type: long
+
+Number of buffers written directly by a backend.
+
+
+[float]
+=== postgresql.bgwriter.buffers.backend_fsync
+
+type: long
+
+Number of times a backend had to execute its own fsync call (normally the background writer handles those even when the backend does its own write)
+
+
+[float]
+=== postgresql.bgwriter.buffers.allocated
+
+type: long
+
+Number of buffers allocated.
+
+
+[float]
+=== postgresql.bgwriter.stats_reset
+
+type: date
+
+Time at which these statistics were last reset.
+
+
 [float]
 == database Fields
 
@@ -3299,7 +3394,8 @@ The hard limit on the number of file descriptors opened by the process. The hard
 [float]
 == cgroup Fields
 
-experimental[] Metrics and limits from the cgroup of which the task is a member. cgroup metrics are reported when the process has membership in a non-root cgroup. These metrics are only available on Linux.
+experimental[]
+Metrics and limits from the cgroup of which the task is a member. cgroup metrics are reported when the process has membership in a non-root cgroup. These metrics are only available on Linux.
 
 
 

metricbeat/docs/modules/postgresql.asciidoc

@@ -23,8 +23,12 @@ metricbeat.modules:
     # Stats about every PostgreSQL database
     #- database
 
+    # Stats about the background writer process's activity
+    #- bgwriter
+
     # Stats about every PostgreSQL process
-    #-activity
+    #- activity
+
   #enabled: true
   #period: 10s
 
@@ -43,9 +47,13 @@ The following metricsets are available:
 
 * <<metricbeat-metricset-postgresql-activity,activity>>
 
+* <<metricbeat-metricset-postgresql-bgwriter,bgwriter>>
+
 * <<metricbeat-metricset-postgresql-database,database>>
 
 include::postgresql/activity.asciidoc[]
 
+include::postgresql/bgwriter.asciidoc[]
+
 include::postgresql/database.asciidoc[]
 

metricbeat/docs/modules/postgresql/bgwriter.asciidoc

@@ -0,0 +1,19 @@
+////
+This file is generated! See scripts/docs_collector.py
+////
+
+[[metricbeat-metricset-postgresql-bgwriter]]
+include::../../../module/postgresql/bgwriter/_meta/docs.asciidoc[]
+
+
+==== Fields
+
+For a description of each field in the metricset, see the
+<<exported-fields-postgresql,exported fields>> section.
+
+Here is an example document generated by this metricset:
+
+[source,json]
+----
+include::../../../module/postgresql/bgwriter/_meta/data.json[]
+----

metricbeat/etc/beat.full.yml

@@ -123,8 +123,12 @@ metricbeat.modules:
     # Stats about every PostgreSQL database
     #- database
 
+    # Stats about the background writer process's activity
+    #- bgwriter
+
     # Stats about every PostgreSQL process
-    #-activity
+    #- activity
+
   #enabled: true
   #period: 10s
 

metricbeat/etc/fields.yml

@@ -885,6 +885,61 @@
                 shows the currently executing query. In all other states, it shows the
                 last query that was executed.
 
+        - name: bgwriter
+          type: group
+          description: >
+            Statistics about the background writer process's activity. Collected using the
+            pg_stat_bgwriter query.
+          fields:
+            - name: checkpoints.scheduled
+              type: long
+              description: >
+                Number of scheduled checkpoints that have been performed.
+            - name: checkpoints.requested
+              type: long
+              description: >
+                Number of requested checkpoints that have been performed.
+            - name: checkpoints.times.write.ms
+              type: float
+              description: >
+                Total amount of time that has been spent in the portion of checkpoint
+                processing where files are written to disk, in milliseconds.
+            - name: checkpoints.times.sync.ms
+              type: float
+              description: >
+                Total amount of time that has been spent in the portion of checkpoint
+                processing where files are synchronized to disk, in milliseconds.
+            - name: buffers.checkpoints
+              type: long
+              description: >
+                Number of buffers written during checkpoints.
+            - name: buffers.clean
+              type: long
+              description: >
+                Number of buffers written by the background writer.
+            - name: buffers.clean_full
+              type: long
+              description: >
+                Number of times the background writer stopped a cleaning scan because it
+                had written too many buffers.
+            - name: buffers.backend
+              type: long
+              description: >
+                Number of buffers written directly by a backend.
+            - name: buffers.backend_fsync
+              type: long
+              description: >
+                Number of times a backend had to execute its own fsync call (normally
+                the background writer handles those even when the backend does its own
+                write)
+            - name: buffers.allocated
+              type: long
+              description: >
+                Number of buffers allocated.
+            - name: stats_reset
+              type: date
+              description: >
+                Time at which these statistics were last reset.
         - name: database
           type: group
           description: >
@@ -1984,7 +2039,9 @@
             - name: cgroup
               type: group
               description: >
-                experimental[] Metrics and limits from the cgroup of which the task is a member.
+                experimental[]
+
+                Metrics and limits from the cgroup of which the task is a member.
                 cgroup metrics are reported when the process has membership in a
                 non-root cgroup. These metrics are only available on Linux.
               fields:

metricbeat/include/list.go

@@ -20,6 +20,7 @@ import (
 	_ "github.com/elastic/beats/metricbeat/module/nginx/stubstatus"
 	_ "github.com/elastic/beats/metricbeat/module/postgresql"
 	_ "github.com/elastic/beats/metricbeat/module/postgresql/activity"
+	_ "github.com/elastic/beats/metricbeat/module/postgresql/bgwriter"
 	_ "github.com/elastic/beats/metricbeat/module/postgresql/database"
 	_ "github.com/elastic/beats/metricbeat/module/redis"
 	_ "github.com/elastic/beats/metricbeat/module/redis/info"

metricbeat/metricbeat.full.yml

@@ -123,8 +123,12 @@ metricbeat.modules:
     # Stats about every PostgreSQL database
     #- database
 
+    # Stats about the background writer process's activity
+    #- bgwriter
+
     # Stats about every PostgreSQL process
-    #-activity
+    #- activity
+
   #enabled: true
   #period: 10s
 

metricbeat/metricbeat.template-es2x.json

@@ -756,6 +756,63 @@
                 }
               }
             },
+            "bgwriter": {
+              "properties": {
+                "buffers": {
+                  "properties": {
+                    "allocated": {
+                      "type": "long"
+                    },
+                    "backend": {
+                      "type": "long"
+                    },
+                    "backend_fsync": {
+                      "type": "long"
+                    },
+                    "checkpoints": {
+                      "type": "long"
+                    },
+                    "clean": {
+                      "type": "long"
+                    },
+                    "clean_full": {
+                      "type": "long"
+                    }
+                  }
+                },
+                "checkpoints": {
+                  "properties": {
+                    "requested": {
+                      "type": "long"
+                    },
+                    "scheduled": {
+                      "type": "long"
+                    },
+                    "times": {
+                      "properties": {
+                        "sync": {
+                          "properties": {
+                            "ms": {
+                              "type": "float"
+                            }
+                          }
+                        },
+                        "write": {
+                          "properties": {
+                            "ms": {
+                              "type": "float"
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                },
+                "stats_reset": {
+                  "type": "date"
+                }
+              }
+            },
             "database": {
               "properties": {
                 "blocks": {

metricbeat/metricbeat.template.json

@@ -742,6 +742,63 @@
                 }
               }
             },
+            "bgwriter": {
+              "properties": {
+                "buffers": {
+                  "properties": {
+                    "allocated": {
+                      "type": "long"
+                    },
+                    "backend": {
+                      "type": "long"
+                    },
+                    "backend_fsync": {
+                      "type": "long"
+                    },
+                    "checkpoints": {
+                      "type": "long"
+                    },
+                    "clean": {
+                      "type": "long"
+                    },
+                    "clean_full": {
+                      "type": "long"
+                    }
+                  }
+                },
+                "checkpoints": {
+                  "properties": {
+                    "requested": {
+                      "type": "long"
+                    },
+                    "scheduled": {
+                      "type": "long"
+                    },
+                    "times": {
+                      "properties": {
+                        "sync": {
+                          "properties": {
+                            "ms": {
+                              "type": "float"
+                            }
+                          }
+                        },
+                        "write": {
+                          "properties": {
+                            "ms": {
+                              "type": "float"
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                },
+                "stats_reset": {
+                  "type": "date"
+                }
+              }
+            },
             "database": {
               "properties": {
                 "blocks": {