feat: gRPC measurement_names support for read buffer (#697)

* test: Add tests for reading data from read buffer in different scenarios

* feat: gRPC measurement_names support for read buffer

server/src/db.rs

@@ -737,20 +737,56 @@ mod test_influxrpc {
     #[async_trait]
     impl DBSetup for TwoMeasurements {
         async fn make(&self) -> Vec<DBScenario> {
-            let db = make_db();
+            let partition_key = "1970-01-01T00";
             let data = "cpu,region=west user=23.2 100\n\
                         cpu,region=west user=21.0 150\n\
                         disk,region=east bytes=99i 200";
 
+            let db = make_db();
             let mut writer = TestLPWriter::default();
-
             writer.write_lp_string(&db, data).await.unwrap();
-            vec![
-                DBScenario {
-                    scenario_name: "Data in open chunk of mutable buffer".into(),
-                    db,
-                }, // todo add a scenario where the database has had data loaded and then deleted
-            ]
+            let scenario1 = DBScenario {
+                scenario_name: "Data in open chunk of mutable buffer".into(),
+                db,
+            };
+
+            let db = make_db();
+            let mut writer = TestLPWriter::default();
+            writer.write_lp_string(&db, data).await.unwrap();
+            db.rollover_partition(partition_key).await.unwrap();
+            let scenario2 = DBScenario {
+                scenario_name: "Data in closed chunk of mutable buffer".into(),
+                db,
+            };
+
+            let db = make_db();
+            let mut writer = TestLPWriter::default();
+            writer.write_lp_string(&db, data).await.unwrap();
+            db.rollover_partition(partition_key).await.unwrap();
+            db.load_chunk_to_read_buffer(partition_key, 0)
+                .await
+                .unwrap();
+            let scenario3 = DBScenario {
+                scenario_name: "Data in both read buffer and mutable buffer".into(),
+                db,
+            };
+
+            let db = make_db();
+            let mut writer = TestLPWriter::default();
+            writer.write_lp_string(&db, data).await.unwrap();
+            db.rollover_partition(partition_key).await.unwrap();
+            db.load_chunk_to_read_buffer(partition_key, 0)
+                .await
+                .unwrap();
+            db.drop_mutable_buffer_chunk(partition_key, 0)
+                .await
+                .unwrap();
+            let scenario4 = DBScenario {
+                scenario_name: "Data in only buffer and not mutable buffer".into(),
+                db,
+            };
+
+            vec![scenario1, scenario2, scenario3, scenario4]
         }
     }
 

server/src/db/chunk.rs

@@ -22,8 +22,11 @@ pub enum Error {
         source: mutable_buffer::chunk::Error,
     },
 
-    #[snafu(display("Read Buffer Chunk Error: {}", source))]
-    ReadBufferChunk { source: read_buffer::Error },
+    #[snafu(display("Read Buffer Error in chunk {}: {}", chunk_id, source))]
+    ReadBufferChunk {
+        source: read_buffer::Error,
+        chunk_id: u32,
+    },
 
     #[snafu(display("Internal Predicate Conversion Error: {}", source))]
     InternalPredicateConversion { source: super::pred::Error },
@@ -113,9 +116,10 @@ impl PartitionChunk for DBChunk {
                 partition_key,
                 chunk_id,
             } => {
+                let chunk_id = *chunk_id;
                 // Translate the predicates to ReadBuffer style
                 let predicate = PredicateBuilder::default().build();
-                let predicate =
+                let rb_predicate =
                     to_read_buffer_predicate(&predicate).context(InternalPredicateConversion)?;
 
                 // translate column selection
@@ -131,11 +135,11 @@ impl PartitionChunk for DBChunk {
                     .read_filter(
                         partition_key,
                         table_name,
-                        &[*chunk_id],
-                        predicate,
+                        &[chunk_id],
+                        rb_predicate,
                         column_selection,
                     )
-                    .context(ReadBufferChunk)?;
+                    .context(ReadBufferChunk { chunk_id })?;
 
                 // copy the RecordBatches into dst
                 dst.extend(read_result);
@@ -167,8 +171,21 @@ impl PartitionChunk for DBChunk {
 
                 make_scan_plan(batch).context(InternalPlanCreation)
             }
-            Self::ReadBuffer { .. } => {
-                unimplemented!("read buffer file not implemented")
+            Self::ReadBuffer {
+                db,
+                partition_key,
+                chunk_id,
+            } => {
+                let chunk_id = *chunk_id;
+
+                let rb_predicate =
+                    to_read_buffer_predicate(&predicate).context(InternalPredicateConversion)?;
+
+                let db = db.read().unwrap();
+                let batch = db
+                    .table_names(partition_key, &[chunk_id], rb_predicate)
+                    .context(ReadBufferChunk { chunk_id })?;
+                make_scan_plan(batch).context(InternalPlanCreation)
             }
             Self::ParquetFile => {
                 unimplemented!("parquet file not implemented")