From a3abed80ff4f2981d5614eaec6e176675b9f1557 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Mon, 1 Jul 2019 17:14:49 +0300
Subject: [PATCH] app/vmselect: do not return empty time series in
`/api/v1/query` result
---
app/vmselect/prometheus/prometheus.go | 4 ++--
app/vmselect/promql/exec.go | 12 ++++++++++--
app/vmselect/promql/exec_test.go | 11 +++++++++--
3 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/app/vmselect/prometheus/prometheus.go b/app/vmselect/prometheus/prometheus.go
index 44d2ace759..806fd22617 100644
--- a/app/vmselect/prometheus/prometheus.go
+++ b/app/vmselect/prometheus/prometheus.go
@@ -501,7 +501,7 @@ func QueryHandler(at *auth.Token, w http.ResponseWriter, r *http.Request) error
DenyPartialResponse: getDenyPartialResponse(r),
}
- result, err := promql.Exec(&ec, query)
+ result, err := promql.Exec(&ec, query, true)
if err != nil {
return fmt.Errorf("cannot execute %q: %s", query, err)
}
@@ -562,7 +562,7 @@ func QueryRangeHandler(at *auth.Token, w http.ResponseWriter, r *http.Request) e
DenyPartialResponse: getDenyPartialResponse(r),
}
- result, err := promql.Exec(&ec, query)
+ result, err := promql.Exec(&ec, query, false)
if err != nil {
return fmt.Errorf("cannot execute %q: %s", query, err)
}
diff --git a/app/vmselect/promql/exec.go b/app/vmselect/promql/exec.go
index 87e474759f..bec9fc9f62 100644
--- a/app/vmselect/promql/exec.go
+++ b/app/vmselect/promql/exec.go
@@ -27,8 +27,8 @@ func ExpandWithExprs(q string) (string, error) {
return string(buf), nil
}
-// Exec executes q for the given ec until the deadline.
-func Exec(ec *EvalConfig, q string) ([]netstorage.Result, error) {
+// Exec executes q for the given ec.
+func Exec(ec *EvalConfig, q string, isFirstPointOnly bool) ([]netstorage.Result, error) {
if *logSlowQueryDuration > 0 {
startTime := time.Now()
defer func() {
@@ -66,6 +66,14 @@ func Exec(ec *EvalConfig, q string) ([]netstorage.Result, error) {
}
ec.End -= ec.Step
+ if isFirstPointOnly {
+ // Remove all the points except the first one from every time series.
+ for _, ts := range rv {
+ ts.Values = ts.Values[:1]
+ ts.Timestamps = ts.Timestamps[:1]
+ }
+ }
+
maySort := maySortResults(e, rv)
result, err := timeseriesToResult(rv, maySort)
if err != nil {
diff --git a/app/vmselect/promql/exec_test.go b/app/vmselect/promql/exec_test.go
index 9612778fe8..8f702c122e 100644
--- a/app/vmselect/promql/exec_test.go
+++ b/app/vmselect/promql/exec_test.go
@@ -72,7 +72,7 @@ func TestExecSuccess(t *testing.T) {
Deadline: netstorage.NewDeadline(time.Minute),
}
for i := 0; i < 5; i++ {
- result, err := Exec(ec, q)
+ result, err := Exec(ec, q, false)
if err != nil {
t.Fatalf(`unexpected error when executing %q: %s`, q, err)
}
@@ -3679,7 +3679,14 @@ func TestExecError(t *testing.T) {
Deadline: netstorage.NewDeadline(time.Minute),
}
for i := 0; i < 4; i++ {
- rv, err := Exec(ec, q)
+ rv, err := Exec(ec, q, false)
+ if err == nil {
+ t.Fatalf(`expecting non-nil error on %q`, q)
+ }
+ if rv != nil {
+ t.Fatalf(`expecting nil rv`)
+ }
+ rv, err = Exec(ec, q, true)
if err == nil {
t.Fatalf(`expecting non-nil error on %q`, q)
}