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TestMessage: account for jitter #6283

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Merged
sougou merged 2 commits into from
Jun 12, 2020
Merged

TestMessage: account for jitter #6283

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a2d068d
TestMessage: account for jitter
rohit-nayak-ps Jun 8, 2020
219ebfb
TestMessage: factor in epoch for jitter calc
rohit-nayak-ps Jun 9, 2020
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22 changes: 14 additions & 8 deletions go/test/endtoend/messaging/message_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -97,6 +97,10 @@ func TestMessage(t *testing.T) {

exec(t, conn, "insert into vitess_message(id, message) values(1, 'hello world')")

// account for jitter in timings, maxJitter uses the current hardcoded value for jitter in message_manager.go
jitter := int64(0)
maxJitter := int64(1.4 * 1e9)

// Consume first message.
start := time.Now().UnixNano()
got, err := streamConn.FetchNext()
Expand All @@ -110,15 +114,16 @@ func TestMessage(t *testing.T) {

qr := exec(t, conn, "select time_next, epoch from vitess_message where id = 1")
next, epoch := getTimeEpoch(qr)
jitter += epoch * maxJitter
// epoch could be 0 or 1, depending on how fast the row is updated
switch epoch {
case 0:
if !(start-1e9 < next && next < start) {
t.Errorf("next: %d. must be within 1s of start: %d", next/1e9, start/1e9)
if !(start-1e9 < next && next < (start+jitter)) {
t.Errorf("next: %d. must be within 1s of start: %d", next/1e9, (start+jitter)/1e9)
}
case 1:
if !(start < next && next < start+3e9) {
t.Errorf("next: %d. must be about 1s after start: %d", next/1e9, start/1e9)
if !(start < next && next < (start+jitter)+3e9) {
t.Errorf("next: %d. must be about 1s after start: %d", next/1e9, (start+jitter)/1e9)
}
default:
t.Errorf("epoch: %d, must be 0 or 1", epoch)
Expand All @@ -129,15 +134,16 @@ func TestMessage(t *testing.T) {
require.NoError(t, err)
qr = exec(t, conn, "select time_next, epoch from vitess_message where id = 1")
next, epoch = getTimeEpoch(qr)
jitter += epoch * maxJitter
// epoch could be 1 or 2, depending on how fast the row is updated
switch epoch {
case 1:
if !(start < next && next < start+3e9) {
t.Errorf("next: %d. must be about 1s after start: %d", next/1e9, start/1e9)
if !(start < next && next < (start+jitter)+3e9) {
t.Errorf("next: %d. must be about 1s after start: %d", next/1e9, (start+jitter)/1e9)
}
case 2:
if !(start+2e9 < next && next < start+6e9) {
t.Errorf("next: %d. must be about 3s after start: %d", next/1e9, start/1e9)
if !(start+2e9 < next && next < (start+jitter)+6e9) {
t.Errorf("next: %d. must be about 3s after start: %d", next/1e9, (start+jitter)/1e9)
Comment on lines +145 to +146
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@derekperkins derekperkins Jun 9, 2020

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Jitter would have happened twice here, so maxJitter would be epoch * 1.333

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@rohit-nayak-ps rohit-nayak-ps Jun 9, 2020

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Thanks, made the change to use epoch*maxJitter. There will no jitter in Epoch 0: is that correct?

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@derekperkins derekperkins Jun 9, 2020

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// have backoff be +/- 33%, whenever this is injected, append (:min_backoff, :jitter)
jitteredBackoff := "FLOOR((%a<<ifnull(epoch, 0)) * %a)"

Correct, no jitter. By default, the jitter is also windowed around the min/max backoff. If there are no settings, minBackoff is the same as ackWaitTimeout and no limit on maxBackoff.

}
default:
t.Errorf("epoch: %d, must be 1 or 2", epoch)
Expand Down