From 54cf820e9115d8908de072c2e6a696e4bf1d3882 Mon Sep 17 00:00:00 2001
From: John Shahid <jvshahid@gmail.com>
Date: Thu, 6 Feb 2014 14:08:35 -0500
Subject: [PATCH] limit the number of keys in the delete batch.

---
 src/datastore/leveldb_datastore.go | 11 +++++++++
 src/integration/benchmark_test.go  | 37 ++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/src/datastore/leveldb_datastore.go b/src/datastore/leveldb_datastore.go
index 2eed8a7c7f..370f9993e2 100644
--- a/src/datastore/leveldb_datastore.go
+++ b/src/datastore/leveldb_datastore.go
@@ -621,12 +621,23 @@ func (self *LevelDbDatastore) deleteRangeOfSeriesCommon(database, series string,
 				}
 			}
 		}
+		count := 0
 		for it = it; it.Valid(); it.Next() {
 			k := it.Key()
 			if len(k) < 16 || !bytes.Equal(k[:8], field.Id) || bytes.Compare(k[8:16], endTimeBytes) == 1 {
 				break
 			}
 			wb.Delete(k)
+			count++
+			// delete every one million keys which is approximately 24 megabytes
+			if count == ONE_MEGABYTE {
+				err = self.db.Write(self.writeOptions, wb)
+				if err != nil {
+					return err
+				}
+				wb.Clear()
+				count = 0
+			}
 			endKey = k
 		}
 		err = self.db.Write(self.writeOptions, wb)
diff --git a/src/integration/benchmark_test.go b/src/integration/benchmark_test.go
index f23e10729d..486fdae346 100644
--- a/src/integration/benchmark_test.go
+++ b/src/integration/benchmark_test.go
@@ -935,6 +935,43 @@ func (self *IntegrationSuite) TestDeleteQuery(c *C) {
 	}
 }
 
+func (self *IntegrationSuite) TestLargeDeletes(c *C) {
+	numberOfPoints := 2 * 1024 * 1024
+	points := []interface{}{}
+	for i := 0; i < numberOfPoints; i++ {
+		points = append(points, []interface{}{i})
+	}
+	pointsString, _ := json.Marshal(points)
+	err := self.server.WriteData(fmt.Sprintf(`
+[
+  {
+    "name": "test_large_deletes",
+    "columns": ["val1"],
+    "points":%s
+  }
+]`, string(pointsString)))
+	c.Assert(err, IsNil)
+	bs, err := self.server.RunQuery("select count(val1) from test_large_deletes", "m")
+	c.Assert(err, IsNil)
+	data := []*h.SerializedSeries{}
+	err = json.Unmarshal(bs, &data)
+	c.Assert(data, HasLen, 1)
+	c.Assert(data[0].Points, HasLen, 1)
+	c.Assert(data[0].Points[0][1], Equals, float64(numberOfPoints))
+
+	query := "delete from test_large_deletes"
+	_, err = self.server.RunQuery(query, "m")
+	c.Assert(err, IsNil)
+
+	// this shouldn't return any data
+	bs, err = self.server.RunQuery("select count(val1) from test_large_deletes", "m")
+	c.Assert(err, IsNil)
+	data = []*h.SerializedSeries{}
+	err = json.Unmarshal(bs, &data)
+	c.Assert(err, IsNil)
+	c.Assert(data, HasLen, 0)
+}
+
 func (self *IntegrationSuite) TestReading(c *C) {
 	if !*benchmark {
 		c.Skip("Benchmarking is disabled")