Set DataFusion runtime configurations through SQL interface

.github/workflows/rust.yml

@@ -693,6 +693,11 @@ jobs:
           # If you encounter an error, run './dev/update_function_docs.sh' and commit
           ./dev/update_function_docs.sh
           git diff --exit-code
+      - name: Check if runtime_configs.md has been modified
+        run: |
+          # If you encounter an error, run './dev/update_runtime_config_docs.sh' and commit
+          ./dev/update_runtime_config_docs.sh
+          git diff --exit-code
 
   # Verify MSRV for the crates which are directly used by other projects:
   # - datafusion

datafusion/core/src/bin/print_runtime_config_docs.rs

@@ -0,0 +1,23 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use datafusion_execution::runtime_env::RuntimeEnvBuilder;
+
+fn main() {
+    let docs = RuntimeEnvBuilder::generate_config_markdown();
+    println!("{}", docs);
+}

datafusion/core/src/execution/context/mod.rs

@@ -35,7 +35,11 @@ use crate::{
     },
     datasource::{provider_as_source, MemTable, ViewTable},
     error::{DataFusionError, Result},
-    execution::{options::ArrowReadOptions, runtime_env::RuntimeEnv, FunctionRegistry},
+    execution::{
+        options::ArrowReadOptions,
+        runtime_env::{RuntimeEnv, RuntimeEnvBuilder},
+        FunctionRegistry,
+    },
     logical_expr::AggregateUDF,
     logical_expr::ScalarUDF,
     logical_expr::{
@@ -1036,13 +1040,73 @@ impl SessionContext {
             variable, value, ..
         } = stmt;
 
-        let mut state = self.state.write();
-        state.config_mut().options_mut().set(&variable, &value)?;
-        drop(state);
+        // Check if this is a runtime configuration
+        if variable.starts_with("datafusion.runtime.") {
+            self.set_runtime_variable(&variable, &value)?;
+        } else {
+            let mut state = self.state.write();
+            state.config_mut().options_mut().set(&variable, &value)?;
+            drop(state);
+        }
 
         self.return_empty_dataframe()
     }
 
+    fn set_runtime_variable(&self, variable: &str, value: &str) -> Result<()> {
+        let key = variable.strip_prefix("datafusion.runtime.").unwrap();
+
+        match key {
+            "memory_limit" => {
+                let memory_limit = Self::parse_memory_limit(value)?;
+
+                let mut state = self.state.write();
+                let mut builder =
+                    RuntimeEnvBuilder::from_runtime_env(state.runtime_env());
+                builder = builder.with_memory_limit(memory_limit, 1.0);
+                *state = SessionStateBuilder::from(state.clone())
+                    .with_runtime_env(Arc::new(builder.build()?))
+                    .build();
+            }
+            _ => {
+                return Err(DataFusionError::Plan(format!(
+                    "Unknown runtime configuration: {}",
+                    variable
+                )))
+            }
+        }
+        Ok(())
+    }
+
+    /// Parse memory limit from string to number of bytes
+    /// Supports formats like '1.5G', '100M', '512K'
+    ///
+    /// # Examples
+    /// ```
+    /// use datafusion::execution::context::SessionContext;
+    ///
+    /// assert_eq!(SessionContext::parse_memory_limit("1M").unwrap(), 1024 * 1024);
+    /// assert_eq!(SessionContext::parse_memory_limit("1.5G").unwrap(), (1.5 * 1024.0 * 1024.0 * 1024.0) as usize);
+    /// ```
+    pub fn parse_memory_limit(limit: &str) -> Result<usize> {
+        let (number, unit) = limit.split_at(limit.len() - 1);
+        let number: f64 = number.parse().map_err(|_| {
+            DataFusionError::Plan(format!(
+                "Failed to parse number from memory limit '{}'",
+                limit
+            ))
+        })?;
+
+        match unit {
+            "K" => Ok((number * 1024.0) as usize),
+            "M" => Ok((number * 1024.0 * 1024.0) as usize),
+            "G" => Ok((number * 1024.0 * 1024.0 * 1024.0) as usize),
+            _ => Err(DataFusionError::Plan(format!(
+                "Unsupported unit '{}' in memory limit '{}'",
+                unit, limit
+            ))),
+        }
+    }
+
     async fn create_custom_table(
         &self,
         cmd: &CreateExternalTable,
@@ -1833,7 +1897,6 @@ mod tests {
     use crate::test;
     use crate::test_util::{plan_and_collect, populate_csv_partitions};
     use arrow::datatypes::{DataType, TimeUnit};
-    use std::env;
     use std::error::Error;
     use std::path::PathBuf;
 

datafusion/core/src/lib.rs

@@ -872,6 +872,12 @@ doc_comment::doctest!(
     user_guide_configs
 );
 
+#[cfg(doctest)]
+doc_comment::doctest!(
+    "../../../docs/source/user-guide/runtime_configs.md",
+    user_guide_runtime_configs
+);
+
 #[cfg(doctest)]
 doc_comment::doctest!(
     "../../../docs/source/user-guide/crate-configuration.md",

datafusion/core/tests/sql/mod.rs

@@ -63,6 +63,7 @@ pub mod create_drop;
 pub mod explain_analyze;
 pub mod joins;
 mod path_partition;
+mod runtime_config;
 pub mod select;
 mod sql_api;
 

datafusion/core/tests/sql/runtime_config.rs

@@ -0,0 +1,166 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! Tests for runtime configuration SQL interface
+
+use std::sync::Arc;
+
+use datafusion::execution::context::SessionContext;
+use datafusion::execution::context::TaskContext;
+use datafusion_physical_plan::common::collect;
+
+#[tokio::test]
+async fn test_memory_limit_with_spill() {
+    let ctx = SessionContext::new();
+
+    ctx.sql("SET datafusion.runtime.memory_limit = '1M'")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+
+    ctx.sql("SET datafusion.execution.sort_spill_reservation_bytes = 0")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+
+    let query = "select * from generate_series(1,10000000) as t1(v1) order by v1;";
+    let df = ctx.sql(query).await.unwrap();
+
+    let plan = df.create_physical_plan().await.unwrap();
+    let task_ctx = Arc::new(TaskContext::from(&ctx.state()));
+    let stream = plan.execute(0, task_ctx).unwrap();
+
+    let _results = collect(stream).await;
+    let metrics = plan.metrics().unwrap();
+    let spill_count = metrics.spill_count().unwrap();
+    assert!(spill_count > 0, "Expected spills but none occurred");
+}
+
+#[tokio::test]
+async fn test_no_spill_with_adequate_memory() {
+    let ctx = SessionContext::new();
+
+    ctx.sql("SET datafusion.runtime.memory_limit = '10M'")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+    ctx.sql("SET datafusion.execution.sort_spill_reservation_bytes = 0")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+
+    let query = "select * from generate_series(1,100000) as t1(v1) order by v1;";
+    let df = ctx.sql(query).await.unwrap();
+
+    let plan = df.create_physical_plan().await.unwrap();
+    let task_ctx = Arc::new(TaskContext::from(&ctx.state()));
+    let stream = plan.execute(0, task_ctx).unwrap();
+
+    let _results = collect(stream).await;
+    let metrics = plan.metrics().unwrap();
+    let spill_count = metrics.spill_count().unwrap();
+    assert_eq!(spill_count, 0, "Expected no spills but some occurred");
+}
+
+#[tokio::test]
+async fn test_multiple_configs() {
+    let ctx = SessionContext::new();
+
+    ctx.sql("SET datafusion.runtime.memory_limit = '100M'")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+    ctx.sql("SET datafusion.execution.batch_size = '2048'")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+
+    let query = "select * from generate_series(1,100000) as t1(v1) order by v1;";
+    let result = ctx.sql(query).await.unwrap().collect().await;
+
+    assert!(result.is_ok(), "Should not fail due to memory limit");
+
+    let state = ctx.state();
+    let batch_size = state.config().options().execution.batch_size;
+    assert_eq!(batch_size, 2048);
+}
+
+#[tokio::test]
+async fn test_memory_limit_enforcement() {
+    let ctx = SessionContext::new();
+
+    ctx.sql("SET datafusion.runtime.memory_limit = '1M'")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+
+    let query = "select * from generate_series(1,100000) as t1(v1) order by v1;";
+    let result = ctx.sql(query).await.unwrap().collect().await;
+
+    assert!(result.is_err(), "Should fail due to memory limit");
+
+    ctx.sql("SET datafusion.runtime.memory_limit = '100M'")
+        .await
+        .unwrap()
+        .collect()
+        .await
+        .unwrap();
+
+    let result = ctx.sql(query).await.unwrap().collect().await;
+
+    assert!(result.is_ok(), "Should not fail due to memory limit");
+}
+
+#[tokio::test]
+async fn test_invalid_memory_limit() {
+    let ctx = SessionContext::new();
+
+    let result = ctx
+        .sql("SET datafusion.runtime.memory_limit = '100X'")
+        .await;
+
+    assert!(result.is_err());
+    let error_message = result.unwrap_err().to_string();
+    assert!(error_message.contains("Unsupported unit 'X'"));
+}
+
+#[tokio::test]
+async fn test_unknown_runtime_config() {
+    let ctx = SessionContext::new();
+
+    let result = ctx
+        .sql("SET datafusion.runtime.unknown_config = 'value'")
+        .await;
+
+    assert!(result.is_err());
+    let error_message = result.unwrap_err().to_string();
+    assert!(error_message.contains("Unknown runtime configuration"));
+}

datafusion/execution/src/runtime_env.rs

@@ -27,7 +27,7 @@ use crate::{
 };
 
 use crate::cache::cache_manager::{CacheManager, CacheManagerConfig};
-use datafusion_common::Result;
+use datafusion_common::{config::ConfigEntry, Result};
 use object_store::ObjectStore;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -268,4 +268,56 @@ impl RuntimeEnvBuilder {
     pub fn build_arc(self) -> Result<Arc<RuntimeEnv>> {
         self.build().map(Arc::new)
     }
+
+    /// Create a new RuntimeEnvBuilder from an existing RuntimeEnv
+    pub fn from_runtime_env(runtime_env: &RuntimeEnv) -> Self {
+        let cache_config = CacheManagerConfig {
+            table_files_statistics_cache: runtime_env
+                .cache_manager
+                .get_file_statistic_cache(),
+            list_files_cache: runtime_env.cache_manager.get_list_files_cache(),
+        };
+
+        Self {
+            disk_manager: DiskManagerConfig::Existing(Arc::clone(
+                &runtime_env.disk_manager,
+            )),
+            memory_pool: Some(Arc::clone(&runtime_env.memory_pool)),
+            cache_manager: cache_config,
+            object_store_registry: Arc::clone(&runtime_env.object_store_registry),
+        }
+    }
+
+    /// Returns a list of all available runtime configurations with their current values and descriptions
+    pub fn entries(&self) -> Vec<ConfigEntry> {
+        // Memory pool configuration
+        vec![ConfigEntry {
+            key: "datafusion.runtime.memory_limit".to_string(),
+            value: None, // Default is system-dependent
+            description: "Maximum memory limit for query execution. Supports suffixes K (kilobytes), M (megabytes), and G (gigabytes). Example: '2G' for 2 gigabytes.",
+        }]
+    }
+
+    /// Generate documentation that can be included in the user guide
+    pub fn generate_config_markdown() -> String {
+        use std::fmt::Write as _;
+
+        let s = Self::default();
+
+        let mut docs = "| key | default | description |\n".to_string();
+        docs += "|-----|---------|-------------|\n";
+        let mut entries = s.entries();
+        entries.sort_unstable_by(|a, b| a.key.cmp(&b.key));
+
+        for entry in &entries {
+            let _ = writeln!(
+                &mut docs,
+                "| {} | {} | {} |",
+                entry.key,
+                entry.value.as_deref().unwrap_or("NULL"),
+                entry.description
+            );
+        }
+        docs
+    }
 }