feat: add list_files_cache table function for datafusion-cli

datafusion-cli/src/functions.rs

@@ -17,13 +17,18 @@
 
 //! Functions that are query-able and searchable via the `\h` command
 
+use datafusion_common::instant::Instant;
 use std::fmt;
 use std::fs::File;
 use std::str::FromStr;
 use std::sync::Arc;
 
-use arrow::array::{Int64Array, StringArray, TimestampMillisecondArray, UInt64Array};
-use arrow::datatypes::{DataType, Field, Schema, SchemaRef, TimeUnit};
+use arrow::array::{
+    DurationMillisecondArray, GenericListArray, Int64Array, StringArray, StructArray,
+    TimestampMillisecondArray, UInt64Array,
+};
+use arrow::buffer::{Buffer, OffsetBuffer, ScalarBuffer};
+use arrow::datatypes::{DataType, Field, Fields, Schema, SchemaRef, TimeUnit};
 use arrow::record_batch::RecordBatch;
 use arrow::util::pretty::pretty_format_batches;
 use datafusion::catalog::{Session, TableFunctionImpl};
@@ -697,3 +702,158 @@ impl TableFunctionImpl for StatisticsCacheFunc {
         Ok(Arc::new(statistics_cache))
     }
 }
+
+#[derive(Debug)]
+struct ListFilesCacheTable {
+    schema: SchemaRef,
+    batch: RecordBatch,
+}
+
+#[async_trait]
+impl TableProvider for ListFilesCacheTable {
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+
+    fn schema(&self) -> arrow::datatypes::SchemaRef {
+        self.schema.clone()
+    }
+
+    fn table_type(&self) -> datafusion::logical_expr::TableType {
+        datafusion::logical_expr::TableType::Base
+    }
+
+    async fn scan(
+        &self,
+        _state: &dyn Session,
+        projection: Option<&Vec<usize>>,
+        _filters: &[Expr],
+        _limit: Option<usize>,
+    ) -> Result<Arc<dyn ExecutionPlan>> {
+        Ok(MemorySourceConfig::try_new_exec(
+            &[vec![self.batch.clone()]],
+            TableProvider::schema(self),
+            projection.cloned(),
+        )?)
+    }
+}
+
+#[derive(Debug)]
+pub struct ListFilesCacheFunc {
+    cache_manager: Arc<CacheManager>,
+}
+
+impl ListFilesCacheFunc {
+    pub fn new(cache_manager: Arc<CacheManager>) -> Self {
+        Self { cache_manager }
+    }
+}
+
+impl TableFunctionImpl for ListFilesCacheFunc {
+    fn call(&self, exprs: &[Expr]) -> Result<Arc<dyn TableProvider>> {
+        if !exprs.is_empty() {
+            return plan_err!("list_files_cache should have no arguments");
+        }
+
+        let nested_fields = Fields::from(vec![
+            Field::new("file_path", DataType::Utf8, false),
+            Field::new(
+                "file_modified",
+                DataType::Timestamp(TimeUnit::Millisecond, None),
+                false,
+            ),
+            Field::new("file_size_bytes", DataType::UInt64, false),
+            Field::new("e_tag", DataType::Utf8, true),
+            Field::new("version", DataType::Utf8, true),
+        ]);
+
+        let metadata_field =
+            Field::new("metadata", DataType::Struct(nested_fields.clone()), true);
+
+        let schema = Arc::new(Schema::new(vec![
+            Field::new("path", DataType::Utf8, false),
+            Field::new("metadata_size_bytes", DataType::UInt64, false),
+            // expires field in ListFilesEntry has type Instant when set, from which we cannot get "the number of seconds", hence using Duration instead of Timestamp as data type.
+            Field::new(
+                "expires_in",
+                DataType::Duration(TimeUnit::Millisecond),
+                true,
+            ),
+            Field::new(
+                "metadata_list",
+                DataType::List(Arc::new(metadata_field.clone())),
+                true,
+            ),
+        ]));
+
+        let mut path_arr = vec![];
+        let mut metadata_size_bytes_arr = vec![];
+        let mut expires_arr = vec![];
+
+        let mut file_path_arr = vec![];
+        let mut file_modified_arr = vec![];
+        let mut file_size_bytes_arr = vec![];
+        let mut etag_arr = vec![];
+        let mut version_arr = vec![];
+        let mut offsets: Vec<i32> = vec![0];
+
+        if let Some(list_files_cache) = self.cache_manager.get_list_files_cache() {
+            let now = Instant::now();
+            let mut current_offset: i32 = 0;
+
+            for (path, entry) in list_files_cache.list_entries() {
+                path_arr.push(path.to_string());
+                metadata_size_bytes_arr.push(entry.size_bytes as u64);
+                // calculates time left before entry expires
+                expires_arr.push(
+                    entry
+                        .expires
+                        .map(|t| t.duration_since(now).as_millis() as i64),
+                );
+
+                for meta in entry.metas.iter() {
+                    file_path_arr.push(meta.location.to_string());
+                    file_modified_arr.push(meta.last_modified.timestamp_millis());
+                    file_size_bytes_arr.push(meta.size);
+                    etag_arr.push(meta.e_tag.clone());
+                    version_arr.push(meta.version.clone());
+                }
+                current_offset += entry.metas.len() as i32;
+                offsets.push(current_offset);
+            }
+        }
+
+        let struct_arr = StructArray::new(
+            nested_fields,
+            vec![
+                Arc::new(StringArray::from(file_path_arr)),
+                Arc::new(TimestampMillisecondArray::from(file_modified_arr)),
+                Arc::new(UInt64Array::from(file_size_bytes_arr)),
+                Arc::new(StringArray::from(etag_arr)),
+                Arc::new(StringArray::from(version_arr)),
+            ],
+            None,
+        );
+
+        let offsets_buffer: OffsetBuffer<i32> =
+            OffsetBuffer::new(ScalarBuffer::from(Buffer::from_vec(offsets)));
+
+        let batch = RecordBatch::try_new(
+            schema.clone(),
+            vec![
+                Arc::new(StringArray::from(path_arr)),
+                Arc::new(UInt64Array::from(metadata_size_bytes_arr)),
+                Arc::new(DurationMillisecondArray::from(expires_arr)),
+                Arc::new(GenericListArray::new(
+                    Arc::new(metadata_field),
+                    offsets_buffer,
+                    Arc::new(struct_arr),
+                    None,
+                )),
+            ],
+        )?;
+
+        let list_files_cache = ListFilesCacheTable { schema, batch };
+        Ok(Arc::new(list_files_cache))
+    }
+}

datafusion-cli/src/main.rs

@@ -32,7 +32,7 @@ use datafusion::logical_expr::ExplainFormat;
 use datafusion::prelude::SessionContext;
 use datafusion_cli::catalog::DynamicObjectStoreCatalog;
 use datafusion_cli::functions::{
-    MetadataCacheFunc, ParquetMetadataFunc, StatisticsCacheFunc,
+    ListFilesCacheFunc, MetadataCacheFunc, ParquetMetadataFunc, StatisticsCacheFunc,
 };
 use datafusion_cli::object_storage::instrumented::{
     InstrumentedObjectStoreMode, InstrumentedObjectStoreRegistry,
@@ -253,6 +253,13 @@ async fn main_inner() -> Result<()> {
         )),
     );
 
+    ctx.register_udtf(
+        "list_files_cache",
+        Arc::new(ListFilesCacheFunc::new(
+            ctx.task_ctx().runtime_env().cache_manager.clone(),
+        )),
+    );
+
     let mut print_options = PrintOptions {
         format: args.format,
         quiet: args.quiet,
@@ -431,15 +438,20 @@ pub fn extract_disk_limit(size: &str) -> Result<usize, String> {
 
 #[cfg(test)]
 mod tests {
+    use std::time::Duration;
+
     use super::*;
     use datafusion::{
         common::test_util::batches_to_string,
         execution::cache::{
-            cache_manager::CacheManagerConfig, cache_unit::DefaultFileStatisticsCache,
+            DefaultListFilesCache, cache_manager::CacheManagerConfig,
+            cache_unit::DefaultFileStatisticsCache,
         },
-        prelude::ParquetReadOptions,
+        prelude::{ParquetReadOptions, col, lit, split_part},
     };
     use insta::assert_snapshot;
+    use object_store::memory::InMemory;
+    use url::Url;
 
     fn assert_conversion(input: &str, expected: Result<usize, String>) {
         let result = extract_memory_pool_size(input);
@@ -741,4 +753,130 @@ mod tests {
 
         Ok(())
     }
+
+    #[tokio::test]
+    async fn test_list_files_cache() -> Result<(), DataFusionError> {
+        let list_files_cache = Arc::new(DefaultListFilesCache::new(
+            1024,
+            Some(Duration::from_secs(1)),
+        ));
+
+        let rt = RuntimeEnvBuilder::new()
+            .with_cache_manager(
+                CacheManagerConfig::default()
+                    .with_list_files_cache(Some(list_files_cache)),
+            )
+            .build_arc()
+            .unwrap();
+
+        let ctx = SessionContext::new_with_config_rt(SessionConfig::default(), rt);
+
+        ctx.register_object_store(
+            &Url::parse("mem://test_table").unwrap(),
+            Arc::new(InMemory::new()),
+        );
+
+        ctx.register_udtf(
+            "list_files_cache",
+            Arc::new(ListFilesCacheFunc::new(
+                ctx.task_ctx().runtime_env().cache_manager.clone(),
+            )),
+        );
+
+        ctx.sql(
+            "CREATE EXTERNAL TABLE src_table
+            STORED AS PARQUET
+            LOCATION '../parquet-testing/data/alltypes_plain.parquet'",
+        )
+        .await?
+        .collect()
+        .await?;
+
+        ctx.sql("COPY (SELECT * FROM src_table) TO 'mem://test_table/0.parquet' STORED AS PARQUET").await?.collect().await?;
+
+        ctx.sql("COPY (SELECT * FROM src_table) TO 'mem://test_table/1.parquet' STORED AS PARQUET").await?.collect().await?;
+
+        ctx.sql(
+            "CREATE EXTERNAL TABLE test_table 
+            STORED AS PARQUET
+            LOCATION 'mem://test_table/'
+        ",
+        )
+        .await?
+        .collect()
+        .await?;
+
+        let sql = "SELECT metadata_size_bytes, expires_in, metadata_list FROM list_files_cache()";
+        let df = ctx
+            .sql(sql)
+            .await?
+            .unnest_columns(&["metadata_list"])?
+            .with_column_renamed("metadata_list", "metadata")?
+            .unnest_columns(&["metadata"])?;
+
+        assert_eq!(
+            2,
+            df.clone()
+                .filter(col("expires_in").is_not_null())?
+                .count()
+                .await?
+        );
+
+        let df = df
+            .with_column_renamed(r#""metadata.file_size_bytes""#, "file_size_bytes")?
+            .with_column_renamed(r#""metadata.e_tag""#, "etag")?
+            .with_column(
+                "filename",
+                split_part(col(r#""metadata.file_path""#), lit("/"), lit(-1)),
+            )?
+            .select_columns(&[
+                "metadata_size_bytes",
+                "filename",
+                "file_size_bytes",
+                "etag",
+            ])?
+            .sort(vec![col("filename").sort(true, false)])?;
+        let rbs = df.collect().await?;
+        assert_snapshot!(batches_to_string(&rbs),@r"
+        +---------------------+-----------+-----------------+------+
+        | metadata_size_bytes | filename  | file_size_bytes | etag |
+        +---------------------+-----------+-----------------+------+
+        | 212                 | 0.parquet | 3645            | 0    |
+        | 212                 | 1.parquet | 3645            | 1    |
+        +---------------------+-----------+-----------------+------+
+        ");
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn test_list_files_cache_not_set() -> Result<(), DataFusionError> {
+        let rt = RuntimeEnvBuilder::new()
+            .with_cache_manager(CacheManagerConfig::default().with_list_files_cache(None))
+            .build_arc()
+            .unwrap();
+
+        let ctx = SessionContext::new_with_config_rt(SessionConfig::default(), rt);
+
+        ctx.register_udtf(
+            "list_files_cache",
+            Arc::new(ListFilesCacheFunc::new(
+                ctx.task_ctx().runtime_env().cache_manager.clone(),
+            )),
+        );
+
+        let rbs = ctx
+            .sql("SELECT * FROM list_files_cache()")
+            .await?
+            .collect()
+            .await?;
+        assert_snapshot!(batches_to_string(&rbs),@r"
+        +------+---------------------+------------+---------------+
+        | path | metadata_size_bytes | expires_in | metadata_list |
+        +------+---------------------+------------+---------------+
+        +------+---------------------+------------+---------------+
+        ");
+
+        Ok(())
+    }
 }

datafusion/execution/src/cache/cache_manager.rs

@@ -16,6 +16,7 @@
 // under the License.
 
 use crate::cache::cache_unit::DefaultFilesMetadataCache;
+use crate::cache::list_files_cache::ListFilesEntry;
 use crate::cache::{CacheAccessor, DefaultListFilesCache};
 use datafusion_common::stats::Precision;
 use datafusion_common::{Result, Statistics};
@@ -93,6 +94,9 @@ pub trait ListFilesCache:
 
     /// Updates the cache with a new TTL (time-to-live).
     fn update_cache_ttl(&self, ttl: Option<Duration>);
+
+    /// Retrieves the information about the entries currently cached.
+    fn list_entries(&self) -> HashMap<Path, ListFilesEntry>;
 }
 
 /// Generic file-embedded metadata used with [`FileMetadataCache`].