Disallow sum_noise(datetime) instead of crashing

Fixes #443

Author: pdobacz

src/query/validation.c

@@ -188,6 +188,11 @@ static bool verify_aggregator(Node *node, void *context)
         aggoid != g_oid_cache.is_suppress_bin)
       FAILWITH_LOCATION(aggref->location, "Unsupported aggregate in query.");
 
+    if ((aggoid == g_oid_cache.sum_noise ||
+         aggoid == g_oid_cache.avg_noise) &&
+        TypeCategory(linitial_oid(aggref->aggargtypes)) == TYPCATEGORY_DATETIME)
+      FAILWITH_LOCATION(aggref->location, "Unsupported aggregate in query.");
+
     if (aggoid == g_oid_cache.count_value || aggoid == g_oid_cache.count_value_noise ||
         is_sum_oid(aggoid) || aggoid == g_oid_cache.sum_noise ||
         is_avg_oid(aggoid) || aggoid == g_oid_cache.avg_noise)

test/expected/validation.out

@@ -403,6 +403,14 @@ SELECT diffix.count_histogram(city) FROM test_validation;
 ERROR:  [PG_DIFFIX] count_histogram argument must be an AID column.
 LINE 1: SELECT diffix.count_histogram(city) FROM test_validation;
                                       ^
+SELECT diffix.sum_noise(last_seen) FROM test_validation;
+ERROR:  [PG_DIFFIX] Unsupported aggregate in query.
+LINE 1: SELECT diffix.sum_noise(last_seen) FROM test_validation;
+               ^
+SELECT diffix.avg_noise(last_seen::date) FROM test_validation;
+ERROR:  [PG_DIFFIX] Unsupported aggregate in query.
+LINE 1: SELECT diffix.avg_noise(last_seen::date) FROM test_validatio...
+               ^
 -- Get rejected because only a subset of expressions is supported for defining buckets.
 SELECT COUNT(*) FROM test_validation GROUP BY LENGTH(city);
 ERROR:  [PG_DIFFIX] Unsupported function used for generalization.

test/sql/validation.sql

@@ -207,6 +207,8 @@ SELECT count(distinct least(id, 5)) FROM test_validation;
 SELECT count(id + 5) FROM test_validation;
 SELECT count(least(id, 5)) FROM test_validation;
 SELECT diffix.count_histogram(city) FROM test_validation;
+SELECT diffix.sum_noise(last_seen) FROM test_validation;
+SELECT diffix.avg_noise(last_seen::date) FROM test_validation;
 
 -- Get rejected because only a subset of expressions is supported for defining buckets.
 SELECT COUNT(*) FROM test_validation GROUP BY LENGTH(city);