table: Add RewriteRows

Author: mmatczuk

Diff for: table/rewrite.go

@@ -0,0 +1,31 @@
+// Copyright (C) 2017 ScyllaDB
+// Use of this source code is governed by a ALv2-style
+// license that can be found in the LICENSE file.
+
+package table
+
+import (
+	"github.com/scylladb/gocqlx/v2"
+)
+
+// RewriteRows performs a sequential rewrite of all rows in a table.
+func RewriteRows(session gocqlx.Session, t *Table, options ...func(q *gocqlx.Queryx)) error {
+	insert := t.InsertQuery(session)
+	defer insert.Release()
+
+	// Apply query options
+	for _, o := range options {
+		o(insert)
+	}
+
+	// Iterate over all rows and reinsert them
+	iter := session.Query(t.SelectAll()).Iter()
+	m := make(map[string]interface{})
+	for iter.MapScan(m) {
+		if err := insert.BindMap(m).Exec(); err != nil {
+			return err
+		}
+		m = make(map[string]interface{})
+	}
+	return iter.Close()
+}

Diff for: table/rewrite_test.go

@@ -0,0 +1,59 @@
+// Copyright (C) 2017 ScyllaDB
+// Use of this source code is governed by a ALv2-style
+// license that can be found in the LICENSE file.
+
+// +build all integration
+
+package table_test
+
+import (
+	"testing"
+	"time"
+
+	. "github.com/scylladb/gocqlx/v2/gocqlxtest"
+	"github.com/scylladb/gocqlx/v2/qb"
+	"github.com/scylladb/gocqlx/v2/table"
+)
+
+func TestRewriteRows(t *testing.T) {
+	session := CreateSession(t)
+	defer session.Close()
+
+	if err := session.ExecStmt(`CREATE TABLE gocqlx_test.rewrite_table (testtext text PRIMARY KEY)`); err != nil {
+		t.Fatal("create table:", err)
+	}
+
+	tbl := table.New(table.Metadata{
+		Name:    "gocqlx_test.rewrite_table",
+		Columns: []string{"testtext"},
+		PartKey: []string{"testtext"},
+	})
+
+	// Insert data with 500ms TTL
+	q := tbl.InsertBuilder().TTL(500 * time.Millisecond).Query(session)
+	if err := q.Bind("a").Exec(); err != nil {
+		t.Fatal("insert:", err)
+	}
+	if err := q.Bind("b").Exec(); err != nil {
+		t.Fatal("insert:", err)
+	}
+	if err := q.Bind("c").Exec(); err != nil {
+		t.Fatal("insert:", err)
+	}
+
+	// Rewrite data without TTL
+	if err := table.RewriteRows(session, tbl); err != nil {
+		t.Fatal("rewrite:", err)
+	}
+
+	// Wait and check if data persisted
+	time.Sleep(time.Second)
+
+	var n int
+	if err := qb.Select(tbl.Name()).CountAll().Query(session).Scan(&n); err != nil {
+		t.Fatal("scan:", err)
+	}
+	if n != 3 {
+		t.Fatal("expected 3 entries")
+	}
+}