title: How can I query all InfluxDB _internal database measurements?
body: <p>I cannot query following measurements from _internal database of InfluxDB using Influxql:</p>
  
  <pre><code>database
  write
  shard
  </code></pre>
  
  <p>See results for following commands:</p>
  
  <pre><code>&gt; show databases
  name: databases
  name
  ----
  _internal
  
  &gt;use _internal
  
  &gt; show measurements
  name: measurements
  name
  ----
  cq
  database
  httpd
  queryExecutor
  runtime
  shard
  subscriber
  tsm1_cache
  tsm1_engine
  tsm1_filestore
  tsm1_wal
  write
  
  &gt; select * from database limit 1;
  ERR: error parsing query: found fron, expected FROM at line 1, char 10
  &gt; select * from write limit 1;
  ERR: error parsing query: found WRITE, expected identifier at line 1, char 15
  &gt; select * from shard limit 1;
  ERR: error parsing query: found SHARD, expected identifier at line 1, char 15
  </code></pre>
  
  <p>But I can successfully query some other measurements</p>
  
  <pre><code>&gt; select * from queryExecutor limit 1;
  name: queryExecutor
  time                hostname              queriesActive queriesExecuted queriesFinished queryDurationNs recoveredPanics
  ----                --------              ------------- --------------- --------------- --------------- ---------------
  1559923260000000000 localhost.localdomain 0             0               0               0               0
  </code></pre>
  
  <p>How can I query/extract data from _internal database of InfluxDB across all measurements availbale?</p>