Performance refactor of running_output buffers

closes #914
closes #967

etc/telegraf.conf

@@ -30,15 +30,13 @@
   ## ie, if interval="10s" then always collect on :00, :10, :20, etc.
   round_interval = true
 
-  ## Telegraf will send metrics to output in batch of at
+  ## Telegraf will send metrics to outputs in batches of at
   ## most metric_batch_size metrics.
   metric_batch_size = 1000
-  ## Telegraf will cache metric_buffer_limit metrics for each output, and will
-  ## flush this buffer on a successful write. This should be a multiple of
-  ## metric_batch_size and could not be less than 2 times metric_batch_size
+  ## For failed writes, telegraf will cache metric_buffer_limit metrics for each
+  ## output, and will flush this buffer on a successful write. Oldest metrics
+  ## are dropped first when this buffer fills.
   metric_buffer_limit = 10000
-  ## Flush the buffer whenever full, regardless of flush_interval.
-  flush_buffer_when_full = true
 
   ## Collection jitter is used to jitter the collection by a random amount.
   ## Each plugin will sleep for a random time within jitter before collecting.
@@ -151,6 +149,15 @@
 #   ## Amazon REGION
 #   region = 'us-east-1'
 # 
+#   ## Amazon Credentials
+#   ## Credentials are loaded in the following order
+#   ## 1) explicit credentials from 'access_key' and 'secret_key'
+#   ## 2) environment variables
+#   ## 3) shared credentials file
+#   ## 4) EC2 Instance Profile
+#   #access_key = ""
+#   #secret_key = ""
+# 
 #   ## Namespace for the CloudWatch MetricDatums
 #   namespace = 'InfluxData/Telegraf'
 
@@ -243,6 +250,16 @@
 # [[outputs.kinesis]]
 #   ## Amazon REGION of kinesis endpoint.
 #   region = "ap-southeast-2"
+# 
+#   ## Amazon Credentials
+#   ## Credentials are loaded in the following order
+#   ## 1) explicit credentials from 'access_key' and 'secret_key'
+#   ## 2) environment variables
+#   ## 3) shared credentials file
+#   ## 4) EC2 Instance Profile
+#   #access_key = ""
+#   #secret_key = ""
+# 
 #   ## Kinesis StreamName must exist prior to starting telegraf.
 #   streamname = "StreamName"
 #   ## PartitionKey as used for sharding data.
@@ -457,6 +474,15 @@
 #   ## Amazon Region
 #   region = 'us-east-1'
 # 
+#   ## Amazon Credentials
+#   ## Credentials are loaded in the following order
+#   ## 1) explicit credentials from 'access_key' and 'secret_key'
+#   ## 2) environment variables
+#   ## 3) shared credentials file
+#   ## 4) EC2 Instance Profile
+#   #access_key = ""
+#   #secret_key = ""
+# 
 #   ## Requested CloudWatch aggregation Period (required - must be a multiple of 60s)
 #   period = '1m'
 # 
@@ -588,8 +614,14 @@
 # [[inputs.filestat]]
 #   ## Files to gather stats about.
 #   ## These accept standard unix glob matching rules, but with the addition of
-#   ## ** as a "super asterisk". See https://github.com/gobwas/glob.
-#   files = ["/etc/telegraf/telegraf.conf", "/var/log/**.log"]
+#   ## ** as a "super asterisk". ie:
+#   ##   "/var/log/**.log"  -> recursively find all .log files in /var/log
+#   ##   "/var/log/*/*.log" -> find all .log files with a parent dir in /var/log
+#   ##   "/var/log/apache.log" -> just tail the apache log file
+#   ##
+#   ## See https://github.com/gobwas/glob for more examples
+#   ##
+#   files = ["/var/log/**.log"]
 #   ## If true, read the entire file and calculate an md5 checksum.
 #   md5 = false
 
@@ -980,6 +1012,11 @@
 #   ## databases are gathered.
 #   ## databases = ["app_production", "testing"]
 #   #
+#   # outputaddress = "db01"
+#   ## A custom name for the database that will be used as the "server" tag in the
+#   ## measurement output. If not specified, a default one generated from
+#   ## the connection address is used.
+#   #
 #   ## Define the toml config where the sql queries are stored
 #   ## New queries can be added, if the withdbname is set to true and there is no
 #   ## databases defined in the 'databases field', the sql query is ended by a
@@ -990,24 +1027,28 @@
 #   ## because the databases variable was set to ['postgres', 'pgbench' ] and the
 #   ## withdbname was true. Be careful that if the withdbname is set to false you
 #   ## don't have to define the where clause (aka with the dbname) the tagvalue
-#   ## field is used to define custom tags (separated by comas)
+#   ## field is used to define custom tags (separated by commas)
+#   ## The optional "measurement" value can be used to override the default
+#   ## output measurement name ("postgresql").
 #   #
 #   ## Structure :
 #   ## [[inputs.postgresql_extensible.query]]
 #   ##   sqlquery string
 #   ##   version string
 #   ##   withdbname boolean
-#   ##   tagvalue string (coma separated)
+#   ##   tagvalue string (comma separated)
+#   ##   measurement string
 #   [[inputs.postgresql_extensible.query]]
 #     sqlquery="SELECT * FROM pg_stat_database"
 #     version=901
 #     withdbname=false
 #     tagvalue=""
+#     measurement=""
 #   [[inputs.postgresql_extensible.query]]
 #     sqlquery="SELECT * FROM pg_stat_bgwriter"
 #     version=901
 #     withdbname=false
-#     tagvalue=""
+#     tagvalue="postgresql.stats"
 
 
 # # Read metrics from one or many PowerDNS servers
@@ -1379,6 +1420,28 @@
 #   percentile_limit = 1000
 
 
+# # Stream a log file, like the tail -f command
+# [[inputs.tail]]
+#   ## files to tail.
+#   ## These accept standard unix glob matching rules, but with the addition of
+#   ## ** as a "super asterisk". ie:
+#   ##   "/var/log/**.log"  -> recursively find all .log files in /var/log
+#   ##   "/var/log/*/*.log" -> find all .log files with a parent dir in /var/log
+#   ##   "/var/log/apache.log" -> just tail the apache log file
+#   ##
+#   ## See https://github.com/gobwas/glob for more examples
+#   ##
+#   files = ["/var/mymetrics.out"]
+#   ## Read file from beginning.
+#   from_beginning = false
+# 
+#   ## Data format to consume.
+#   ## Each data format has it's own unique set of configuration options, read
+#   ## more about them here:
+#   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
+#   data_format = "influx"
+
+
 # # Generic TCP listener
 # [[inputs.tcp_listener]]
 #   ## Address and port to host TCP listener on