From 86f1e4788833342056c62b103f144b89ada72fbe Mon Sep 17 00:00:00 2001
From: Pete Kruckenberg <pete@kruckenberg.com>
Date: Sat, 18 Jul 2015 07:36:15 -0600
Subject: [PATCH] compute continuous queries back to 'recompute-no-older-than',
 bucketing with GROUP BY clause

---
 etc/config.sample.toml                     |  1 -
 services/continuous_querier/config.go      |  9 ---------
 services/continuous_querier/config_test.go |  5 +----
 services/continuous_querier/service.go     | 23 +---------------------
 4 files changed, 2 insertions(+), 36 deletions(-)

diff --git a/etc/config.sample.toml b/etc/config.sample.toml
index 7aa78980f1c..990f44ed6b0 100644
--- a/etc/config.sample.toml
+++ b/etc/config.sample.toml
@@ -172,7 +172,6 @@ reporting-disabled = false
 
 [continuous_queries]
   enabled = true
-  recompute-previous-n = 2
   recompute-no-older-than = "10m"
   compute-runs-per-interval = 10
   compute-no-more-than = "2m"
diff --git a/services/continuous_querier/config.go b/services/continuous_querier/config.go
index d6f08aea77a..3806d527f24 100644
--- a/services/continuous_querier/config.go
+++ b/services/continuous_querier/config.go
@@ -7,8 +7,6 @@ import (
 )
 
 const (
-	DefaultRecomputePreviousN = 2
-
 	DefaultRecomputeNoOlderThan = 10 * time.Minute
 
 	DefaultComputeRunsPerInterval = 10
@@ -21,12 +19,6 @@ type Config struct {
 	// If this flag is set to false, both the brokers and data nodes should ignore any CQ processing.
 	Enabled bool `toml:"enabled"`
 
-	// when continuous queries are run we'll automatically recompute previous intervals
-	// in case lagged data came in. Set to zero if you never have lagged data. We do
-	// it this way because invalidating previously computed intervals would be insanely hard
-	// and expensive.
-	RecomputePreviousN int `toml:"recompute-previous-n"`
-
 	// The RecomputePreviousN setting provides guidance for how far back to recompute, the RecomputeNoOlderThan
 	// setting sets a ceiling on how far back in time it will go. For example, if you have 2 PreviousN
 	// and have this set to 10m, then we'd only compute the previous two intervals for any
@@ -53,7 +45,6 @@ type Config struct {
 func NewConfig() Config {
 	return Config{
 		Enabled:                true,
-		RecomputePreviousN:     DefaultRecomputePreviousN,
 		RecomputeNoOlderThan:   toml.Duration(DefaultRecomputeNoOlderThan),
 		ComputeRunsPerInterval: DefaultComputeRunsPerInterval,
 		ComputeNoMoreThan:      toml.Duration(DefaultComputeNoMoreThan),
diff --git a/services/continuous_querier/config_test.go b/services/continuous_querier/config_test.go
index 2a0edc4f2d7..c1f7317fed7 100644
--- a/services/continuous_querier/config_test.go
+++ b/services/continuous_querier/config_test.go
@@ -12,7 +12,6 @@ func TestConfig_Parse(t *testing.T) {
 	// Parse configuration.
 	var c continuous_querier.Config
 	if _, err := toml.Decode(`
-recompute-previous-n = 1
 recompute-no-older-than = "10s"
 compute-runs-per-interval = 2
 compute-no-more-than = "20s"
@@ -22,9 +21,7 @@ enabled = true
 	}
 
 	// Validate configuration.
-	if c.RecomputePreviousN != 1 {
-		t.Fatalf("unexpected recompute previous n: %d", c.RecomputePreviousN)
-	} else if time.Duration(c.RecomputeNoOlderThan) != 10*time.Second {
+	if time.Duration(c.RecomputeNoOlderThan) != 10*time.Second {
 		t.Fatalf("unexpected recompute no older than: %v", c.RecomputeNoOlderThan)
 	} else if c.ComputeRunsPerInterval != 2 {
 		t.Fatalf("unexpected compute runs per interval: %d", c.ComputeRunsPerInterval)
diff --git a/services/continuous_querier/service.go b/services/continuous_querier/service.go
index df5d640552e..62c55944c05 100644
--- a/services/continuous_querier/service.go
+++ b/services/continuous_querier/service.go
@@ -230,7 +230,7 @@ func (s *Service) ExecuteContinuousQuery(dbi *meta.DatabaseInfo, cqi *meta.Conti
 		startTime = startTime.Add(-interval)
 	}
 
-	if err := cq.q.SetTimeRange(startTime, startTime.Add(interval)); err != nil {
+	if err := cq.q.SetTimeRange(now.Add(-time.Duration(s.Config.RecomputeNoOlderThan)), startTime.Add(interval)); err != nil {
 		s.Logger.Printf("error setting time range: %s\n", err)
 	}
 
@@ -240,27 +240,6 @@ func (s *Service) ExecuteContinuousQuery(dbi *meta.DatabaseInfo, cqi *meta.Conti
 		return err
 	}
 
-	recomputeNoOlderThan := time.Duration(s.Config.RecomputeNoOlderThan)
-
-	for i := 0; i < s.Config.RecomputePreviousN; i++ {
-		// if we're already more time past the previous window than we're going to look back, stop
-		if now.Sub(startTime) > recomputeNoOlderThan {
-			return nil
-		}
-		newStartTime := startTime.Add(-interval)
-
-		if err := cq.q.SetTimeRange(newStartTime, startTime); err != nil {
-			s.Logger.Printf("error setting time range: %s\n", err)
-			return err
-		}
-
-		if err := s.runContinuousQueryAndWriteResult(cq); err != nil {
-			s.Logger.Printf("error during recompute previous: %s. running: %s\n", err, cq.q.String())
-			return err
-		}
-
-		startTime = newStartTime
-	}
 	return nil
 }