add comments of all_tables in MetaProvider.

apache · Apr 24, 2023 · 48e5ed0 · 48e5ed0
1 parent 4ce7193
commit 48e5ed0
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Showing 2 changed files with 5 additions and 3 deletions.
diff --git a/query_frontend/src/influxql/planner.rs b/query_frontend/src/influxql/planner.rs
@@ -7,9 +7,7 @@ use std::{cell::OnceCell, sync::Arc};
 use arrow::datatypes::SchemaRef as ArrowSchemaRef;
 use common_util::error::BoxError;
 use datafusion::{
-    error::DataFusionError,
-    logical_expr::TableSource,
-    sql::{planner::ContextProvider, TableReference},
+    error::DataFusionError, logical_expr::TableSource, sql::planner::ContextProvider,
 };
 use influxql_logical_planner::plan::{
     ceresdb_schema_to_influxdb, InfluxQLToLogicalPlan, SchemaProvider,

diff --git a/query_frontend/src/provider.rs b/query_frontend/src/provider.rs
@@ -89,6 +89,10 @@ pub trait MetaProvider {
     fn aggregate_udf(&self, name: &str) -> Result<Option<AggregateUdf>>;
 
     /// Return all tables.
+    ///
+    /// Note that it may incur expensive cost.
+    /// Now it is used in `table_names` method in `SchemaProvider`(introduced by
+    /// influxql).
     fn all_tables(&self) -> Result<Vec<TableRef>>;
 }