Enable setting default values for target_partitions and planning_concurrency

datafusion/common/src/config.rs

@@ -768,7 +768,18 @@ impl ConfigField for ConfigOptions {
         let (key, rem) = key.split_once('.').unwrap_or((key, ""));
         match key {
             "catalog" => self.catalog.set(rem, value),
-            "execution" => self.execution.set(rem, value),
+            "execution" => {
+                let value = match (rem, value) {
+                    ("target_partitions", "0") => {
+                        &ExecutionOptions::default().target_partitions.to_string()
+                    }
+                    ("planning_concurrency", "0") => {
+                        &ExecutionOptions::default().planning_concurrency.to_string()
+                    }
+                    _ => value,
+                };
+                self.execution.set(rem, value)
+            }
             "optimizer" => self.optimizer.set(rem, value),
             "explain" => self.explain.set(rem, value),
             "sql_parser" => self.sql_parser.set(rem, value),

datafusion/execution/src/config.rs

@@ -193,9 +193,11 @@ impl SessionConfig {
     ///
     /// [`target_partitions`]: datafusion_common::config::ExecutionOptions::target_partitions
     pub fn with_target_partitions(mut self, n: usize) -> Self {
-        // partition count must be greater than zero
-        assert!(n > 0);
-        self.options.execution.target_partitions = n;
+        self.options.execution.target_partitions = if n == 0 {
+            datafusion_common::config::ExecutionOptions::default().target_partitions
+        } else {
+            n
+        };
         self
     }
 

datafusion/sqllogictest/test_files/information_schema.slt

@@ -149,6 +149,39 @@ drop table t
 statement ok
 drop table t2
 
+
+############
+## 0 to represent the default value (target_partitions and planning_concurrency)
+###########
+
+statement ok
+SET datafusion.execution.target_partitions = 3;
+
+statement ok
+SET datafusion.execution.planning_concurrency = 3;
+
+# when setting target_partitions and planning_concurrency to 3, their values will be 3
+query TB rowsort
+SELECT name, value = 3 FROM information_schema.df_settings WHERE name IN ('datafusion.execution.target_partitions', 'datafusion.execution.planning_concurrency');
+----
+datafusion.execution.planning_concurrency true
+datafusion.execution.target_partitions true
+
+statement ok
+SET datafusion.execution.target_partitions = 0;
+
+statement ok
+SET datafusion.execution.planning_concurrency = 0;
+
+# when setting target_partitions and planning_concurrency to 0, their values will be equal to the
+# default values, which are different from 0 (which is invalid)
+query TB rowsort
+SELECT name, value = 0 FROM information_schema.df_settings WHERE name IN ('datafusion.execution.target_partitions', 'datafusion.execution.planning_concurrency');
+----
+datafusion.execution.planning_concurrency false
+datafusion.execution.target_partitions false
+
+
 ############
 ## SHOW VARIABLES should work
 ###########