From fdf6ac4ac763fd14c4f944eb716fc689acd41f4e Mon Sep 17 00:00:00 2001
From: Zach Musgrave <zach@liquidata.co>
Date: Thu, 5 Dec 2019 12:42:03 -0800
Subject: [PATCH] Couple performance fixes: 1) cache the SQL schema for a
 table, and 2) only update output every 500 lines. Together these give us a
 60% speedup on a large import.

Signed-off-by: Zach Musgrave <zach@liquidata.co>
---
 go/cmd/dolt/commands/sql.go          | 13 ++++++++++--
 go/libraries/doltcore/sqle/tables.go | 30 +++++++++++++++-------------
 2 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/go/cmd/dolt/commands/sql.go b/go/cmd/dolt/commands/sql.go
index a8ebec1060..5295fc9f4e 100755
--- a/go/cmd/dolt/commands/sql.go
+++ b/go/cmd/dolt/commands/sql.go
@@ -201,6 +201,8 @@ func runBatchMode(ctx context.Context, se *sqlEngine) error {
 		query = ""
 	}
 
+	updateBatchInsertOutput()
+	
 	if err := scanner.Err(); err != nil {
 		cli.Println(err.Error())
 	}
@@ -472,6 +474,7 @@ var batchEditStats stats
 var displayStrLen int
 
 const maxBatchSize = 50000
+const updateInterval = 500
 
 // Processes a single query in batch mode. The Root of the sqlEngine may or may not be changed.
 func processBatchQuery(ctx context.Context, query string, se *sqlEngine) error {
@@ -499,8 +502,9 @@ func processBatchQuery(ctx context.Context, query string, se *sqlEngine) error {
 			}
 		}
 
-		displayStr := fmt.Sprintf("Rows inserted: %d", batchEditStats.numRowsInserted)
-		displayStrLen = cli.DeleteAndPrint(displayStrLen, displayStr)
+		if batchEditStats.numRowsInserted%updateInterval == 0 {
+			updateBatchInsertOutput()
+		}
 
 		return nil
 	default:
@@ -520,6 +524,11 @@ func processBatchQuery(ctx context.Context, query string, se *sqlEngine) error {
 	}
 }
 
+func updateBatchInsertOutput() {
+	displayStr := fmt.Sprintf("Rows inserted: %d", batchEditStats.numRowsInserted)
+	displayStrLen = cli.DeleteAndPrint(displayStrLen, displayStr)
+}
+
 // Updates the batch insert stats with the results of an insert operation.
 func mergeInsertResultIntoStats(rowIter sql.RowIter, s *stats) error {
 	for {
diff --git a/go/libraries/doltcore/sqle/tables.go b/go/libraries/doltcore/sqle/tables.go
index f68bb676e2..b4f013baad 100644
--- a/go/libraries/doltcore/sqle/tables.go
+++ b/go/libraries/doltcore/sqle/tables.go
@@ -30,11 +30,12 @@ import (
 
 // DoltTable implements the sql.Table interface and gives access to dolt table rows and schema.
 type DoltTable struct {
-	name  string
-	table *doltdb.Table
-	sch   schema.Schema
-	db    *Database
-	ed    *tableEditor
+	name   string
+	table  *doltdb.Table
+	sch    schema.Schema
+	sqlSch sql.Schema
+	db     *Database
+	ed     *tableEditor
 }
 
 var _ sql.Table = (*DoltTable)(nil)
@@ -78,20 +79,21 @@ func (t *DoltTable) String() string {
 
 // Schema returns the schema for this table.
 func (t *DoltTable) Schema() sql.Schema {
-	// TODO: fix panics
-	sch, err := t.table.GetSchema(context.TODO())
-
-	if err != nil {
-		panic(err)
-	}
-
-	// TODO: fix panics
-	sqlSch, err := doltSchemaToSqlSchema(t.name, sch)
+	return t.sqlSchema()
+}
 
+func (t *DoltTable) sqlSchema() sql.Schema {
+	if t.sqlSch != nil {
+		return t.sqlSch
+	}
+
+	// TODO: fix panics
+	sqlSch, err := doltSchemaToSqlSchema(t.name, t.sch)
 	if err != nil {
 		panic(err)
 	}
 
+	t.sqlSch = sqlSch
 	return sqlSch
 }