feat: expose SST index metadata via information schema

src/catalog/src/system_schema/information_schema.rs

@@ -48,7 +48,7 @@ use datatypes::schema::SchemaRef;
 use lazy_static::lazy_static;
 use paste::paste;
 use process_list::InformationSchemaProcessList;
-use store_api::sst_entry::{ManifestSstEntry, StorageSstEntry};
+use store_api::sst_entry::{ManifestSstEntry, PuffinIndexMetaEntry, StorageSstEntry};
 use store_api::storage::{ScanRequest, TableId};
 use table::TableRef;
 use table::metadata::TableType;
@@ -68,7 +68,7 @@ use crate::system_schema::information_schema::region_peers::InformationSchemaReg
 use crate::system_schema::information_schema::runtime_metrics::InformationSchemaMetrics;
 use crate::system_schema::information_schema::schemata::InformationSchemaSchemata;
 use crate::system_schema::information_schema::ssts::{
-    InformationSchemaSstsManifest, InformationSchemaSstsStorage,
+    InformationSchemaSstsIndexMeta, InformationSchemaSstsManifest, InformationSchemaSstsStorage,
 };
 use crate::system_schema::information_schema::table_constraints::InformationSchemaTableConstraints;
 use crate::system_schema::information_schema::tables::InformationSchemaTables;
@@ -263,6 +263,9 @@ impl SystemSchemaProviderInner for InformationSchemaProvider {
             SSTS_STORAGE => Some(Arc::new(InformationSchemaSstsStorage::new(
                 self.catalog_manager.clone(),
             )) as _),
+            SSTS_INDEX_META => Some(Arc::new(InformationSchemaSstsIndexMeta::new(
+                self.catalog_manager.clone(),
+            )) as _),
             _ => None,
         }
     }
@@ -342,6 +345,10 @@ impl InformationSchemaProvider {
                 SSTS_STORAGE.to_string(),
                 self.build_table(SSTS_STORAGE).unwrap(),
             );
+            tables.insert(
+                SSTS_INDEX_META.to_string(),
+                self.build_table(SSTS_INDEX_META).unwrap(),
+            );
         }
 
         tables.insert(TABLES.to_string(), self.build_table(TABLES).unwrap());
@@ -456,6 +463,8 @@ pub enum DatanodeInspectKind {
     SstManifest,
     /// List SST entries discovered in storage layer
     SstStorage,
+    /// List index metadata collected from manifest
+    SstIndexMeta,
 }
 
 impl DatanodeInspectRequest {
@@ -464,6 +473,7 @@ impl DatanodeInspectRequest {
         match self.kind {
             DatanodeInspectKind::SstManifest => ManifestSstEntry::build_plan(self.scan),
             DatanodeInspectKind::SstStorage => StorageSstEntry::build_plan(self.scan),
+            DatanodeInspectKind::SstIndexMeta => PuffinIndexMetaEntry::build_plan(self.scan),
         }
     }
 }

src/catalog/src/system_schema/information_schema/ssts.rs

@@ -15,20 +15,22 @@
 use std::sync::{Arc, Weak};
 
 use common_catalog::consts::{
-    INFORMATION_SCHEMA_SSTS_MANIFEST_TABLE_ID, INFORMATION_SCHEMA_SSTS_STORAGE_TABLE_ID,
+    INFORMATION_SCHEMA_SSTS_INDEX_META_TABLE_ID, INFORMATION_SCHEMA_SSTS_MANIFEST_TABLE_ID,
+    INFORMATION_SCHEMA_SSTS_STORAGE_TABLE_ID,
 };
 use common_error::ext::BoxedError;
 use common_recordbatch::SendableRecordBatchStream;
 use common_recordbatch::adapter::AsyncRecordBatchStreamAdapter;
 use datatypes::schema::SchemaRef;
 use snafu::ResultExt;
-use store_api::sst_entry::{ManifestSstEntry, StorageSstEntry};
+use store_api::sst_entry::{ManifestSstEntry, PuffinIndexMetaEntry, StorageSstEntry};
 use store_api::storage::{ScanRequest, TableId};
 
 use crate::CatalogManager;
 use crate::error::{ProjectSchemaSnafu, Result};
 use crate::information_schema::{
-    DatanodeInspectKind, DatanodeInspectRequest, InformationTable, SSTS_MANIFEST, SSTS_STORAGE,
+    DatanodeInspectKind, DatanodeInspectRequest, InformationTable, SSTS_INDEX_META, SSTS_MANIFEST,
+    SSTS_STORAGE,
 };
 use crate::system_schema::utils;
 
@@ -140,3 +142,58 @@ impl InformationTable for InformationSchemaSstsStorage {
         )))
     }
 }
+
+/// Information schema table for index metadata.
+pub struct InformationSchemaSstsIndexMeta {
+    schema: SchemaRef,
+    catalog_manager: Weak<dyn CatalogManager>,
+}
+
+impl InformationSchemaSstsIndexMeta {
+    pub(super) fn new(catalog_manager: Weak<dyn CatalogManager>) -> Self {
+        Self {
+            schema: PuffinIndexMetaEntry::schema(),
+            catalog_manager,
+        }
+    }
+}
+
+impl InformationTable for InformationSchemaSstsIndexMeta {
+    fn table_id(&self) -> TableId {
+        INFORMATION_SCHEMA_SSTS_INDEX_META_TABLE_ID
+    }
+
+    fn table_name(&self) -> &'static str {
+        SSTS_INDEX_META
+    }
+
+    fn schema(&self) -> SchemaRef {
+        self.schema.clone()
+    }
+
+    fn to_stream(&self, request: ScanRequest) -> Result<SendableRecordBatchStream> {
+        let schema = if let Some(p) = &request.projection {
+            Arc::new(self.schema.try_project(p).context(ProjectSchemaSnafu)?)
+        } else {
+            self.schema.clone()
+        };
+
+        let info_ext = utils::information_extension(&self.catalog_manager)?;
+        let req = DatanodeInspectRequest {
+            kind: DatanodeInspectKind::SstIndexMeta,
+            scan: request,
+        };
+
+        let future = async move {
+            info_ext
+                .inspect_datanode(req)
+                .await
+                .map_err(BoxedError::new)
+                .context(common_recordbatch::error::ExternalSnafu)
+        };
+        Ok(Box::pin(AsyncRecordBatchStreamAdapter::new(
+            schema,
+            Box::pin(future),
+        )))
+    }
+}

src/catalog/src/system_schema/information_schema/table_names.rs

@@ -50,3 +50,4 @@ pub const REGION_STATISTICS: &str = "region_statistics";
 pub const PROCESS_LIST: &str = "process_list";
 pub const SSTS_MANIFEST: &str = "ssts_manifest";
 pub const SSTS_STORAGE: &str = "ssts_storage";
+pub const SSTS_INDEX_META: &str = "ssts_index_meta";

src/common/catalog/src/consts.rs

@@ -108,6 +108,8 @@ pub const INFORMATION_SCHEMA_PROCESS_LIST_TABLE_ID: u32 = 36;
 pub const INFORMATION_SCHEMA_SSTS_MANIFEST_TABLE_ID: u32 = 37;
 /// id for information_schema.ssts_storage
 pub const INFORMATION_SCHEMA_SSTS_STORAGE_TABLE_ID: u32 = 38;
+/// id for information_schema.ssts_index_meta
+pub const INFORMATION_SCHEMA_SSTS_INDEX_META_TABLE_ID: u32 = 39;
 
 // ----- End of information_schema tables -----
 

src/datanode/src/region_server/catalog.rs

@@ -27,18 +27,20 @@ use datafusion_expr::{LogicalPlan, TableSource};
 use futures::TryStreamExt;
 use session::context::QueryContextRef;
 use snafu::{OptionExt, ResultExt};
-use store_api::sst_entry::{ManifestSstEntry, StorageSstEntry};
+use store_api::sst_entry::{ManifestSstEntry, PuffinIndexMetaEntry, StorageSstEntry};
 use store_api::storage::RegionId;
 
 use crate::error::{DataFusionSnafu, ListStorageSstsSnafu, Result, UnexpectedSnafu};
 use crate::region_server::RegionServer;
 
 /// Reserved internal table kinds used.
 /// These are recognized by reserved table names and mapped to providers.
+#[allow(clippy::enum_variant_names)]
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Copy)]
 enum InternalTableKind {
     InspectSstManifest,
     InspectSstStorage,
+    InspectSstIndexMeta,
 }
 
 impl InternalTableKind {
@@ -50,6 +52,9 @@ impl InternalTableKind {
         if name.eq_ignore_ascii_case(StorageSstEntry::reserved_table_name_for_inspection()) {
             return Some(Self::InspectSstStorage);
         }
+        if name.eq_ignore_ascii_case(PuffinIndexMetaEntry::reserved_table_name_for_inspection()) {
+            return Some(Self::InspectSstIndexMeta);
+        }
         None
     }
 
@@ -58,6 +63,7 @@ impl InternalTableKind {
         match self {
             Self::InspectSstManifest => server.inspect_sst_manifest_provider().await,
             Self::InspectSstStorage => server.inspect_sst_storage_provider().await,
+            Self::InspectSstIndexMeta => server.inspect_sst_index_meta_provider().await,
         }
     }
 }
@@ -103,6 +109,25 @@ impl RegionServer {
         let table = MemTable::try_new(schema, vec![vec![batch]]).context(DataFusionSnafu)?;
         Ok(Arc::new(table))
     }
+
+    /// Expose index metadata across the engine as an in-memory table.
+    pub async fn inspect_sst_index_meta_provider(&self) -> Result<Arc<dyn TableProvider>> {
+        let mito = {
+            let guard = self.inner.mito_engine.read().unwrap();
+            guard.as_ref().cloned().context(UnexpectedSnafu {
+                violated: "mito engine not available",
+            })?
+        };
+
+        let entries = mito.all_index_metas().await;
+        let schema = PuffinIndexMetaEntry::schema().arrow_schema().clone();
+        let batch = PuffinIndexMetaEntry::to_record_batch(&entries)
+            .map_err(DataFusionError::from)
+            .context(DataFusionSnafu)?;
+
+        let table = MemTable::try_new(schema, vec![vec![batch]]).context(DataFusionSnafu)?;
+        Ok(Arc::new(table))
+    }
 }
 
 /// A catalog list that resolves `TableProvider` by table name:

src/store-api/src/sst_entry.rs

@@ -356,6 +356,15 @@ impl PuffinIndexMetaEntry {
     pub fn reserved_table_name_for_inspection() -> &'static str {
         "__inspect/__mito/__puffin_index_meta"
     }
+
+    /// Builds a logical plan for scanning puffin index metadata entries.
+    pub fn build_plan(scan_request: ScanRequest) -> Result<LogicalPlan, DataFusionError> {
+        build_plan_helper(
+            scan_request,
+            Self::reserved_table_name_for_inspection(),
+            Self::schema(),
+        )
+    }
 }
 
 fn build_plan_helper(