Datafusion-cli: Redesign the datafusion-cli execution and print, make it totally streaming printing without memory overhead (#14877)

* Inital version for streaming batch preview

* Add more reasonable code

* polish code

* polish code

* Add unit test

* fmt

* remove println

Author: zhuqi-lucas

datafusion-cli/src/exec.rs

@@ -26,12 +26,6 @@ use crate::{
     object_storage::get_object_store,
     print_options::{MaxRows, PrintOptions},
 };
-use futures::StreamExt;
-use std::collections::HashMap;
-use std::fs::File;
-use std::io::prelude::*;
-use std::io::BufReader;
-
 use datafusion::common::instant::Instant;
 use datafusion::common::{plan_datafusion_err, plan_err};
 use datafusion::config::ConfigFileType;
@@ -41,13 +35,15 @@ use datafusion::logical_expr::{DdlStatement, LogicalPlan};
 use datafusion::physical_plan::execution_plan::EmissionType;
 use datafusion::physical_plan::{execute_stream, ExecutionPlanProperties};
 use datafusion::sql::parser::{DFParser, Statement};
-use datafusion::sql::sqlparser::dialect::dialect_from_str;
-
-use datafusion::execution::memory_pool::MemoryConsumer;
-use datafusion::physical_plan::spill::get_record_batch_memory_size;
 use datafusion::sql::sqlparser;
+use datafusion::sql::sqlparser::dialect::dialect_from_str;
 use rustyline::error::ReadlineError;
 use rustyline::Editor;
+use std::collections::HashMap;
+use std::fs::File;
+use std::io::prelude::*;
+use std::io::BufReader;
+use std::sync::Arc;
 use tokio::signal;
 
 /// run and execute SQL statements and commands, against a context with the given print options
@@ -230,18 +226,17 @@ pub(super) async fn exec_and_print(
     for statement in statements {
         let adjusted =
             AdjustedPrintOptions::new(print_options.clone()).with_statement(&statement);
-
         let plan = create_plan(ctx, statement).await?;
         let adjusted = adjusted.with_plan(&plan);
 
         let df = ctx.execute_logical_plan(plan).await?;
         let physical_plan = df.create_physical_plan().await?;
 
-        // Track memory usage for the query result if it's bounded
-        let mut reservation =
-            MemoryConsumer::new("DataFusion-Cli").register(task_ctx.memory_pool());
+        let is_unbounded = physical_plan.boundedness().is_unbounded();
+        let mut stream = execute_stream(Arc::clone(&physical_plan), task_ctx.clone())?;
 
-        if physical_plan.boundedness().is_unbounded() {
+        // Both bounded and unbounded streams are streaming prints
+        if is_unbounded {
             if physical_plan.pipeline_behavior() == EmissionType::Final {
                 return plan_err!(
                     "The given query can generate a valid result only once \
@@ -250,37 +245,43 @@ pub(super) async fn exec_and_print(
             }
             // As the input stream comes, we can generate results.
             // However, memory safety is not guaranteed.
-            let stream = execute_stream(physical_plan, task_ctx.clone())?;
-            print_options.print_stream(stream, now).await?;
+            print_options
+                .print_stream(MaxRows::Unlimited, stream, now)
+                .await?;
         } else {
             // Bounded stream; collected results size is limited by the maxrows option
             let schema = physical_plan.schema();
-            let mut stream = execute_stream(physical_plan, task_ctx.clone())?;
-            let mut results = vec![];
-            let mut row_count = 0_usize;
             let max_rows = match print_options.maxrows {
                 MaxRows::Unlimited => usize::MAX,
                 MaxRows::Limited(n) => n,
             };
-            while let Some(batch) = stream.next().await {
-                let batch = batch?;
-                let curr_num_rows = batch.num_rows();
-                // Stop collecting results if the number of rows exceeds the limit
-                // results batch should include the last batch that exceeds the limit
-                if row_count < max_rows + curr_num_rows {
-                    // Try to grow the reservation to accommodate the batch in memory
-                    reservation.try_grow(get_record_batch_memory_size(&batch))?;
-                    results.push(batch);
-                }
-                row_count += curr_num_rows;
+            let stdout = std::io::stdout();
+            let mut writer = stdout.lock();
+
+            // If we don't want to print the table, we should use the streaming print same as above
+            if print_options.format != PrintFormat::Table
+                && print_options.format != PrintFormat::Automatic
+            {
+                print_options
+                    .print_stream(print_options.maxrows, stream, now)
+                    .await?;
+                continue;
             }
+
+            // into_inner will finalize the print options to table if it's automatic
             adjusted
                 .into_inner()
-                .print_batches(schema, &results, now, row_count)?;
-            reservation.free();
+                .print_table_batch(
+                    print_options,
+                    schema,
+                    &mut stream,
+                    max_rows,
+                    &mut writer,
+                    now,
+                )
+                .await?;
         }
     }
-
     Ok(())
 }