vttablet throttler feature flag: -enable-lag-throttler#6815
vttablet throttler feature flag: -enable-lag-throttler#6815deepthi merged 5 commits intovitessio:masterfrom
Conversation
Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
shlomi-noach
requested review from
derekperkins,
dkhenry,
harshit-gangal,
rohit-nayak-ps and
systay
as code owners
| -init_tablet_type $tablet_type \ | ||
| -health_check_interval 5s \ | ||
| -heartbeat_enable \ | ||
| -heartbeat_interval 250ms \ |
There was a problem hiding this comment.
These were committed earlier by mistake.
| -enable_semi_sync \ | ||
| -enable_replication_reporter \ | ||
| -heartbeat_enable \ | ||
| -heartbeat_interval 250ms \ |
There was a problem hiding this comment.
These were committed earlier by mistake.
| } | ||
| if rt.forceHeartbeat { | ||
| rt.hw.Open() | ||
| } |
There was a problem hiding this comment.
when throttler runs, we need heartbeat writer to run. We do not need the reader because throttler reads directly from _vt.heartbeat table.
There was a problem hiding this comment.
Just a note that we could be calling Open and Close twice, but that is fine since they are idempotent.
There was a problem hiding this comment.
👍 that was my understanding as well.
| throttler.shard = shard | ||
| go throttler.Operate(context.Background()) | ||
| if throttler.env.Config().EnableLagThrottler { | ||
| go throttler.Operate(context.Background()) |
There was a problem hiding this comment.
Operate() is where the throttler does all the hard work. If throttler is not enabled, we skip it altogether.
Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
|
Noteworthy, when the throttler is disabled, the endpoint |
| // Check is the main serving function of the throttler, and returns a check result for this cluster's lag | ||
| func (throttler *Throttler) Check(ctx context.Context, appName string, remoteAddr string, flags *CheckFlags) (checkResult *CheckResult) { | ||
| if !throttler.env.Config().EnableLagThrottler { | ||
| return okMetricCheckResult |
There was a problem hiding this comment.
When the throttler is disabled, Check() always responds with HTTP 200 OK
|
This branch is incorporated inside #6547 |
|
I'm ready to have this PR reviewed and merged. |
| func newHeartbeatWriter(env tabletenv.Env, alias topodatapb.TabletAlias) *heartbeatWriter { | ||
| config := env.Config() | ||
|
|
||
| // config.EnableLagThrottler is a feature flag for the throttler; if throttler runs, then heartbeat must also run |
There was a problem hiding this comment.
It is not clear why the changes in this file are required, but I'll trust the tests :)
| func (w *heartbeatWriter) enableWrites(enable bool) { | ||
| if w.ticks == nil { | ||
| return | ||
| } |
There was a problem hiding this comment.
@deepthi this change is actually reverting my previous change in the throttler PR. This if statement was originally here.
| // config.EnableLagThrottler is a feature flag for the throttler; if throttler runs, then heartbeat must also run | ||
| if config.ReplicationTracker.Mode != tabletenv.Heartbeat && !config.EnableLagThrottler { | ||
| return &heartbeatWriter{} | ||
| } |
There was a problem hiding this comment.
@deepthi this change is actually reverting my previous change in the throttler PR. This if statement was originally here.
There was a problem hiding this comment.
(except of course now added && !config.EnableLagThrottler)
3 participants
followup to #6668
This PR introduces
-enable-lag-throttlerfeature flag (bool). By default-enable-lag-throttlerisfalse.When
-enable-lag-throttler=true, the vttablet throttler functionality is activated:cc @aquarapid