Merge pull request #24062 from amosbird/projection-fix1

Fix empty key projection query analysis

src/Interpreters/Aggregator.cpp

@@ -1894,9 +1894,12 @@ void NO_INLINE Aggregator::mergeWithoutKeyStreamsImpl(
         res = place;
     }
 
+    if (block.rows() > 0)
+    {
         /// Adding Values
         for (size_t i = 0; i < params.aggregates_size; ++i)
             aggregate_functions[i]->merge(res + offsets_of_aggregate_states[i], (*aggregate_columns[i])[0], result.aggregates_pool);
+    }
 
     /// Early release memory.
     block.clear();

src/Processors/Transforms/AggregatingTransform.cpp

@@ -546,7 +546,12 @@ void AggregatingTransform::initGenerate()
     /// If there was no data, and we aggregate without keys, and we must return single row with the result of empty aggregation.
     /// To do this, we pass a block with zero rows to aggregate.
     if (variants.empty() && params->params.keys_size == 0 && !params->params.empty_result_for_aggregation_by_empty_set)
+    {
+        if (params->only_merge)
+            params->aggregator.mergeBlock(getInputs().front().getHeader(), variants, no_more_keys);
+        else
             params->aggregator.executeOnBlock(getInputs().front().getHeader(), variants, key_columns, aggregate_columns, no_more_keys);
+    }
 
     double elapsed_seconds = watch.elapsedSeconds();
     size_t rows = variants.sizeWithoutOverflowRow();

src/Storages/MergeTree/MergeTreeData.cpp

@@ -4041,7 +4041,7 @@ bool MergeTreeData::getQueryProcessingStageWithAggregateProjection(
             auto required_columns = candidate.before_aggregation->foldActionsByProjection(keys, projection.sample_block_for_keys);
             // std::cerr << fmt::format("before_aggregation = \n{}", candidate.before_aggregation->dumpDAG()) << std::endl;
             // std::cerr << fmt::format("aggregate_required_columns = \n{}", fmt::join(required_columns, ", ")) << std::endl;
-            if (required_columns.empty())
+            if (required_columns.empty() && !keys.empty())
                 continue;
 
             if (analysis_result.optimize_aggregation_in_order)

src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp

@@ -161,7 +161,11 @@ QueryPlanPtr MergeTreeDataSelectExecutor::read(
             query_info.merge_tree_data_select_cache.get());
     }
 
-    LOG_DEBUG(log, "Choose projection {}", query_info.projection->desc->name);
+    LOG_DEBUG(
+        log,
+        "Choose {} projection {}",
+        ProjectionDescription::typeToString(query_info.projection->desc->type),
+        query_info.projection->desc->name);
 
     if (query_info.projection->merge_tree_data_select_base_cache->sum_marks
             + query_info.projection->merge_tree_data_select_projection_cache->sum_marks

tests/queries/0_stateless/01710_projections.reference

@@ -3,3 +3,5 @@
 2020-10-24 00:00:00	1.3619605237696326	0.16794469697335793	0.7637956767025532	0.8899329799574005	0.6227685185389797	0.30795997278638165	0.7637956767025532
 2020-10-24 00:00:00	19	-1.9455094931672063	0.7759802460082872	0.6	0
 2020-10-24 00:00:00	852	894
+2	-1
+999

tests/queries/0_stateless/01710_projections.sql

@@ -38,4 +38,14 @@ select toStartOfMinute(datetime) dt_m, domain, sum(retry_count) / sum(duration),
 
 select toStartOfHour(toStartOfMinute(datetime)) dt_h, uniqHLL12(x_id), uniqHLL12(y_id) from projection_test group by dt_h order by dt_h;
 
+-- found by fuzzer
+SELECT 2, -1 FROM projection_test PREWHERE domain_alias = 1. WHERE domain = NULL GROUP BY -9223372036854775808 ORDER BY countIf(first_time = 0) / count(-2147483649) DESC NULLS LAST, 1048576 DESC NULLS LAST;
+
 drop table if exists projection_test;
+
+drop table if exists projection_without_key;
+create table projection_without_key (key UInt32, PROJECTION x (SELECT max(key))) engine MergeTree order by key;
+insert into projection_without_key select number from numbers(1000);
+set force_optimize_projection = 1, allow_experimental_projection_optimization = 1;
+select max(key) from projection_without_key;
+drop table projection_without_key;