Slightly faster evaluation of the tag suffix 'has_data'.

New aggregation type 'not_null'.
New unit 'boolean'.
New unit group 'group_boolean'.

bin/weewx/defaults.py

@@ -61,6 +61,7 @@ log_failure = False
         group_volume       = gallon
 
         # The following are used internally and should not be changed:
+        group_boolean      = boolean
         group_count        = count
         group_interval     = minute
         group_time         = unix_epoch
@@ -69,10 +70,11 @@ log_failure = False
     # The following section sets the formatting for each type of unit.
     [[StringFormats]]
 
+        boolean            = %d
         centibar           = %.0f
         cm                 = %.2f
         cm_per_hour        = %.2f
-        count              = %.0f
+        count              = %d
         degree_C           = %.1f
         degree_F           = %.1f
         degree_compass     = %.0f
@@ -107,6 +109,7 @@ log_failure = False
     # The following section sets the label to be used for each type of unit
     [[Labels]]
 
+        boolean           = ""
         centibar          = " cb"
         cm                = " cm"
         cm_per_hour       = " cm/h"

bin/weewx/manager.py

@@ -258,9 +258,8 @@ class Manager(object):
         data.
         """
 
-        # return self.exists(obs_type) and self.getAggregate(timespan, obs_type, 'count')[0] != 0
         return self.exists(obs_type) \
-               and weewx.xtypes.get_aggregate(obs_type, timespan, 'count', self)[0]
+               and weewx.xtypes.get_aggregate(obs_type, timespan, 'not_null', self)[0]
 
     def addRecord(self, record_obj,
                   accumulator=None,

bin/weewx/tests/expected/StandardTest/index.html

@@ -458,7 +458,15 @@
       <td>Test tag "has_data" with existent type that has data $day.outTemp.has_data</td>
       <td>TRUE</td>
     </tr>
-      <tr>
+    <tr>
+      <td>Test tag "not_null" with existent type that has no data $day.UV.not_null</td>
+      <td>0</td>
+    </tr>
+    <tr>
+      <td>Test tag "not_null" with existent type that has data $day.outTemp.not_null</td>
+      <td>1</td>
+    </tr>
+    <tr>
       <td>Test for a bad observation type on a $day tag: $day.foobar.min</td>
       <td>$day.foobar.min</td>
     </tr>

bin/weewx/tests/expected/StandardTest/metric/index.html

@@ -458,7 +458,15 @@
       <td>Test tag "has_data" with existent type that has data $day.outTemp.has_data</td>
       <td>TRUE</td>
     </tr>
-      <tr>
+    <tr>
+      <td>Test tag "not_null" with existent type that has no data $day.UV.not_null</td>
+      <td>0</td>
+    </tr>
+    <tr>
+      <td>Test tag "not_null" with existent type that has data $day.outTemp.not_null</td>
+      <td>1</td>
+    </tr>
+    <tr>
       <td>Test for a bad observation type on a $day tag: $day.foobar.min</td>
       <td>$day.foobar.min</td>
     </tr>

bin/weewx/tests/test_skins/StandardTest/index.html.tmpl

@@ -458,7 +458,15 @@ FALSE#slurp
       <td>Test tag "has_data" with existent type that has data \$day.outTemp.has_data</td>
       <td>$emit_boolean($day.outTemp.has_data)</td>
     </tr>
-      <tr>
+    <tr>
+      <td>Test tag "not_null" with existent type that has no data \$day.UV.not_null</td>
+      <td>$day.UV.not_null</td>
+    </tr>
+    <tr>
+      <td>Test tag "not_null" with existent type that has data \$day.outTemp.not_null</td>
+      <td>$day.outTemp.not_null</td>
+    </tr>
+    <tr>
       <td>Test for a bad observation type on a \$day tag: \$day.foobar.min</td>
       <td>$day.foobar.min</td>
     </tr>

bin/weewx/units.py

@@ -227,6 +227,7 @@ agg_group = {
     'min_le'     : "group_count",
     'minmaxtime' : "group_time",
     'mintime'    : "group_time",
+    'not_null'   : "group_boolean",
     'sum_ge'     : "group_count",
     'sum_le'     : "group_count",
     'vecdir'     : "group_direction",
@@ -239,6 +240,7 @@ agg_group = {
 USUnits = ListOfDicts({
     "group_altitude"    : "foot",
     "group_amp"         : "amp",
+    "group_boolean"     : "boolean",
     "group_concentration": "microgram_per_meter_cubed",
     "group_count"       : "count",
     "group_data"        : "byte",
@@ -276,6 +278,7 @@ USUnits = ListOfDicts({
 MetricUnits = ListOfDicts({
     "group_altitude"    : "meter",
     "group_amp"         : "amp",
+    "group_boolean"     : "boolean",
     "group_concentration": "microgram_per_meter_cubed",
     "group_count"       : "count",
     "group_data"        : "byte",
@@ -468,6 +471,7 @@ conversionDict = {
 default_unit_format_dict = {
     "amp"                : "%.1f",
     "bit"                : "%.0f",
+    "boolean"            : "%d",
     "byte"               : "%.0f",
     "centibar"           : "%.0f",
     "cm"                 : "%.2f",

bin/weewx/xtypes.py

@@ -240,6 +240,8 @@ class ArchiveTable(XType):
         'mintime': "SELECT dateTime FROM %(table_name)s "
                    "WHERE dateTime > %(start)s AND dateTime <= %(stop)s "
                    "AND %(obs_type)s IS NOT NULL ORDER BY %(obs_type)s ASC LIMIT 1",
+        'not_null': "SELECT %(obs_type)s IS NOT NULL FROM %(table_name)s "
+                    "WHERE dateTime > %(start)s AND dateTime <= %(stop)s LIMIT 1",
         'tderiv': "SELECT (b.%(obs_type)s - a.%(obs_type)s) / (b.dateTime-a.dateTime) "
                   "FROM archive a, archive b "
                   "WHERE b.dateTime = (SELECT MAX(dateTime) FROM archive "
@@ -383,6 +385,8 @@ class DailySummaries(XType):
                    "WHERE dateTime >= %(start)s AND dateTime < %(stop)s "
                    "AND mintime IS NOT NULL "
                    "ORDER BY min ASC, mintime ASC LIMIT 1",
+        'not_null': "SELECT count>0 FROM %(table_name)s_day_%(obs_key)s "
+                 "WHERE dateTime >= %(start)s AND dateTime < %(stop)s LIMIT 1",
         'rms': "SELECT SUM(wsquaresum),SUM(sumtime) FROM %(table_name)s_day_%(obs_key)s "
                "WHERE dateTime >= %(start)s AND dateTime < %(stop)s",
         'sum': "SELECT SUM(sum) FROM %(table_name)s_day_%(obs_key)s "
@@ -469,7 +473,7 @@ class DailySummaries(XType):
 
         elif aggregate_type in ['mintime', 'maxmintime', 'maxtime', 'minmaxtime', 'maxsumtime',
                                 'minsumtime', 'count', 'max_ge', 'max_le', 'min_ge', 'min_le',
-                                'sum_ge', 'sum_le', 'avg_ge', 'avg_le']:
+                                'not_null', 'sum_ge', 'sum_le', 'avg_ge', 'avg_le']:
             # These aggregates are always integers:
             value = int(row[0])
 

docs/changes.txt

@@ -116,6 +116,9 @@ service.
 
 Added option --batch-size to the Vantage version of wee_device. See PR #693.
 
+Slightly faster evaluation of the tag suffix 'has_data'.
+New aggregation type 'not_null'.
+
 
 4.4.0 01/30/2021
 

docs/customizing.htm

@@ -7031,6 +7031,12 @@ growing_base = 50.0, degree_F</pre>
                     <a href="#ValueTuple"><span class="code">ValueTuple</span></a>.
                 </td>
             </tr>
+            <tr>
+                <td class="first_col code">not_null</td>
+                <td>
+                    Returns truthy if any value over the aggregation period is non-null.
+                </td>
+            </tr>
             <tr>
                 <td class="first_col code">rms</td>
                 <td>The root mean square value in the aggregation period.
@@ -7141,6 +7147,14 @@ growing_base = 50.0, degree_F</pre>
                 <td>amp</td>
                 <td>amp</td>
             </tr>
+            <tr>
+                <td class="first_col">group_boolean</td>
+                <td></td>
+                <td>boolean</td>
+                <td>boolean</td>
+                <td>boolean</td>
+                <td>boolean</td>
+            </tr>
             <tr>
                 <td class="first_col">group_concentration</td>
                 <td>no2<br/>pm1_0<br/>pm2_5<br/>pm10_0</td>