feat: add tracing support tag_keys

db/src/chunk.rs

@@ -457,9 +457,14 @@ impl QueryChunk for DbChunk {
 
     fn column_names(
         &self,
+        mut ctx: IOxExecutionContext,
         predicate: &Predicate,
         columns: Selection<'_>,
     ) -> Result<Option<StringSet>, Self::Error> {
+        ctx.set_metadata("storage", self.state.state_name());
+        ctx.set_metadata("projection", format!("{}", columns));
+        ctx.set_metadata("predicate", format!("{}", &predicate));
+
         match &self.state {
             State::MutableBuffer { chunk, .. } => {
                 if !predicate.is_empty() {
@@ -477,17 +482,20 @@ impl QueryChunk for DbChunk {
                         return Ok(None);
                     }
                 };
+                ctx.set_metadata("rb_predicate", format!("{}", &rb_predicate));
 
                 self.access_recorder.record_access();
                 // TODO(edd): wire up delete predicates to be pushed down to
                 // the read buffer.
-                Ok(Some(
-                    chunk
-                        .column_names(rb_predicate, vec![], columns, BTreeSet::new())
-                        .context(ReadBufferChunkSnafu {
-                            chunk_id: self.id(),
-                        })?,
-                ))
+
+                let names = chunk
+                    .column_names(rb_predicate, vec![], columns, BTreeSet::new())
+                    .context(ReadBufferChunkSnafu {
+                        chunk_id: self.id(),
+                    })?;
+                ctx.set_metadata("output_values", names.len() as i64);
+
+                Ok(Some(names))
             }
             State::ParquetFile { chunk, .. } => {
                 if !predicate.is_empty() {
@@ -619,7 +627,11 @@ mod tests {
 
         let t2 = time.inc(Duration::from_secs(1));
         let column_names = snapshot
-            .column_names(&Default::default(), Selection::All)
+            .column_names(
+                IOxExecutionContext::default(),
+                &Default::default(),
+                Selection::All,
+            )
             .unwrap()
             .is_some();
         let m4 = chunk.access_recorder().get_metrics();

influxdb_iox/src/influxdb_ioxd/planner.rs

@@ -75,7 +75,8 @@ impl Planner {
     where
         D: QueryDatabase + 'static,
     {
-        let planner = InfluxRpcPlanner::default();
+        let planner =
+            InfluxRpcPlanner::new().with_execution_context(self.ctx.child_ctx("influxrpc_planner"));
 
         self.ctx
             .run(async move {

ingester/src/query.rs

@@ -191,6 +191,7 @@ impl QueryChunk for QueryableBatch {
     /// this Chunk. Returns `None` otherwise
     fn column_names(
         &self,
+        _ctx: IOxExecutionContext,
         _predicate: &Predicate,
         _columns: Selection<'_>,
     ) -> Result<Option<StringSet>, Self::Error> {

query/src/frontend/influxrpc.rs

@@ -333,6 +333,7 @@ impl InfluxRpcPlanner {
     where
         D: QueryDatabase + 'static,
     {
+        let ctx = self.ctx.child_ctx("tag_keys planning");
         debug!(?rpc_predicate, "planning tag_keys");
 
         // Special case predicates that span the entire valid timestamp range
@@ -385,7 +386,11 @@ impl InfluxRpcPlanner {
                 if !do_full_plan {
                     // filter the columns further from the predicate
                     let maybe_names = chunk
-                        .column_names(predicate, selection)
+                        .column_names(
+                            ctx.child_ctx("column_names execution"),
+                            predicate,
+                            selection,
+                        )
                         .map_err(|e| Box::new(e) as _)
                         .context(FindingColumnNamesSnafu)?;
 

query/src/lib.rs

@@ -191,6 +191,7 @@ pub trait QueryChunk: QueryChunkMeta + Debug + Send + Sync {
     /// this Chunk. Returns `None` otherwise
     fn column_names(
         &self,
+        ctx: IOxExecutionContext,
         predicate: &Predicate,
         columns: Selection<'_>,
     ) -> Result<Option<StringSet>, Self::Error>;

query/src/test.rs

@@ -961,6 +961,7 @@ impl QueryChunk for TestChunk {
 
     fn column_names(
         &self,
+        _ctx: IOxExecutionContext,
         predicate: &Predicate,
         selection: Selection<'_>,
     ) -> Result<Option<StringSet>, Self::Error> {