perf(explore): emit the index status on change, not every three seconds

`IndexStatusChanged` was pushed on a 3 s ticker for the life of the
process, byte-identical once the index was ready, and `config-page`
assigns it to a @state field — so a user who had once opened Settings
paid a full re-render of a 2 000-line template every 3 s, forever, for
no news. Measured sitting on Settings: 5 events and 5 re-renders per
15 s, against 0 and 0.

`emitStatus` drops a status equal to the last one it sent, which is
the rule stated once instead of at twenty call sites. The corollary is
load-bearing: every mutation of something the status derives must now
call `emitStatus` itself. Two were relying on the ticker — `si.ready`
when an existing index is adopted, and `si.cancel` when a build ends —
and without them the header badge said "Building search index" over an
index the settings page called ready. A polling loop is a hidden
dependency for every state transition that forgot to announce itself.
This commit is contained in:
2026-08-12 01:18:07 -04:00
parent 952c25c3d3
commit a37acfcf84
2 changed files with 264 additions and 18 deletions
+184
View File
@@ -0,0 +1,184 @@
package explore
import (
"context"
"log/slog"
"testing"
"yellowjacket/backend/database"
"yellowjacket/backend/events"
)
// The index status used to be pushed on a 3 s ticker for the life of
// the process, with a byte-identical payload once the index was ready.
// The frontend's handler assigns it to a @state field, so every tick
// re-rendered the whole settings page — a cached view that never
// unmounts — saying nothing (`perf.M6` / `H-14`).
//
// The ticker is gone and emitStatus suppresses an unchanged payload, so
// what these cover is the pair of properties that replaced it: a change
// still gets through, and a non-change does not.
// setupRecordedIndex builds a SearchIndex with an event sink installed,
// so what the frontend would receive is assertable in-process.
func setupRecordedIndex(t *testing.T) (*SearchIndex, *events.Recorder) {
t.Helper()
db := database.NewTestDB(t)
si := NewSearchIndex(db, nil, nil, slog.Default())
rec := events.NewRecorder()
si.SetContext(events.WithSink(context.Background(), rec))
return si, rec
}
func TestEmitStatus_SuppressesAnUnchangedPayload(t *testing.T) {
si, rec := setupRecordedIndex(t)
// SetContext emits once via refreshStatusCounts; everything after
// this describes the same state.
rec.Reset()
for range 5 {
si.emitStatus()
}
if got := rec.Count(events.IndexStatusChanged); got != 0 {
t.Fatalf(
"emitted %d IndexStatusChanged for an unchanged status, want 0",
got,
)
}
}
func TestEmitStatus_EmitsOnChange(t *testing.T) {
si, rec := setupRecordedIndex(t)
rec.Reset()
si.setTierStatus("artists", "running", 100, 10)
if got := rec.Count(events.IndexStatusChanged); got != 1 {
t.Fatalf("emitted %d IndexStatusChanged for a new tier, want 1", got)
}
// Progress within the tier is a change too — this is what a build
// reports, and dropping it would freeze the progress bar.
si.setTierStatus("artists", "running", 100, 20)
if got := rec.Count(events.IndexStatusChanged); got != 2 {
t.Fatalf("emitted %d after progress moved, want 2", got)
}
// The same call again is not.
si.setTierStatus("artists", "running", 100, 20)
if got := rec.Count(events.IndexStatusChanged); got != 2 {
t.Fatalf("emitted %d after a repeated status, want 2", got)
}
}
// The status carries a slice, so a snapshot that aliases it would
// compare equal to a later mutation of the same backing array and the
// change would never be emitted.
func TestEmitStatus_SnapshotDoesNotAliasTiers(t *testing.T) {
si, rec := setupRecordedIndex(t)
si.setTierStatus("artists", "running", 100, 10)
rec.Reset()
si.setTierStatus("artists", "complete", 100, 100)
if got := rec.Count(events.IndexStatusChanged); got != 1 {
t.Fatalf(
"emitted %d when a tier completed in place, want 1", got,
)
}
status, ok := rec.Last(events.IndexStatusChanged)
if !ok {
t.Fatal("no IndexStatusChanged recorded")
}
payload, ok := status.Payload().(IndexStatus)
if !ok {
t.Fatalf("payload is %T, want explore.IndexStatus", status.Payload())
}
if len(payload.Tiers) != 1 || payload.Tiers[0].State != "complete" {
t.Fatalf("payload tiers = %+v, want one complete tier", payload.Tiers)
}
}
// `Building` and `Ready` are derived inside emitStatus from fields the
// dedupe never sees directly, so a transition in either has to survive
// it. A build ending is the case that matters: syncIndexJob only
// resolves the job in the registry on a sync reporting Building false,
// and suppressing that left the header badge saying "Building search
// index" over an index the settings page called ready.
func TestEmitStatus_BuildingTransitionsAreNotSuppressed(t *testing.T) {
si, rec := setupRecordedIndex(t)
si.mu.Lock()
_, si.cancel = context.WithCancel(context.Background())
si.mu.Unlock()
si.emitStatus()
rec.Reset()
// Nothing else changed, so this one is noise.
si.emitStatus()
if got := rec.Count(events.IndexStatusChanged); got != 0 {
t.Fatalf("emitted %d while still building unchanged, want 0", got)
}
si.mu.Lock()
si.cancel = nil
si.mu.Unlock()
si.emitStatus()
ev, ok := rec.Last(events.IndexStatusChanged)
if !ok {
t.Fatalf("a build ending emitted nothing; got %v", rec.Names())
}
payload, ok := ev.Payload().(IndexStatus)
if !ok {
t.Fatalf("payload is %T, want explore.IndexStatus", ev.Payload())
}
if payload.Building {
t.Fatal("payload still reports building after the build ended")
}
}
// Becoming ready used to be the one status mutation with no emit behind
// it; the ticker carried it, so removing the ticker without an explicit
// emit would have left the settings page reading "not ready" forever
// over a fully built index.
func TestEmitStatus_ReadyIsAChange(t *testing.T) {
si, rec := setupRecordedIndex(t)
rec.Reset()
si.mu.Lock()
si.ready = true
si.mu.Unlock()
si.emitStatus()
ev, ok := rec.Last(events.IndexStatusChanged)
if !ok {
t.Fatalf("becoming ready emitted nothing; got %v", rec.Names())
}
payload, ok := ev.Payload().(IndexStatus)
if !ok {
t.Fatalf("payload is %T, want explore.IndexStatus", ev.Payload())
}
if !payload.Ready {
t.Fatal("payload reports not ready after si.ready was set")
}
}
+80 -18
View File
@@ -199,6 +199,13 @@ type SearchIndex struct {
// Build status tracking — read by GetIndexStatus for the UI.
buildStatus IndexStatus
// lastEmitted is the status most recently pushed to the frontend, so
// an unchanged one can be dropped rather than re-rendering the whole
// settings page for nothing. It has its own mutex: emitStatus is
// called from paths that already hold mu for reading.
emitMu sync.Mutex
lastEmitted *IndexStatus
// jobs is the background job registry; buildPaused records that the
// user paused the build, distinguishing a deliberate stop from a
// build that merely finished. Both are protected by mu.
@@ -267,24 +274,16 @@ func (si *SearchIndex) SetContext(ctx context.Context) {
si.mu.Unlock()
// Load current row counts + last-built timestamp from DB.
//
// There is deliberately no ticker here. This used to emit the status
// every 3 seconds for the life of the process, with a byte-identical
// payload once the index was ready — which re-rendered the whole of
// `config-page` on every tick, since it is a cached view that never
// unmounts. Every path that mutates the status already calls
// emitStatus, that call now suppresses an unchanged payload, and the
// frontend seeds itself with GetIndexStatus() on connect rather than
// waiting for the next tick.
si.refreshStatusCounts()
// Start a background ticker that emits status every 3 seconds.
// This replaces frontend polling — the Wails binding dispatcher
// can be blocked by other calls, but EventsEmit bypasses it.
go func() {
ticker := time.NewTicker(3 * time.Second)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
return
case <-ticker.C:
si.emitStatus()
}
}
}()
}
// EnsureArtistDiscography lazily fetches an artist's top release groups
@@ -522,6 +521,14 @@ func (si *SearchIndex) StartBuild(ctx context.Context) {
si.cancel = nil
si.mu.Unlock()
// `Building` is derived from si.cancel, so clearing it is a
// status change and has to say so. This is what resolves the
// job in the registry — syncIndexJob only finishes a job on a
// sync that reports Building false, and without this line the
// header badge reads "Building search index" over an index the
// settings page calls ready.
si.emitStatus()
close(si.done)
// The index rows (and their popularities) may have changed, so
@@ -677,7 +684,38 @@ func (si *SearchIndex) setTierDetail(name, state string, total, completed int, d
si.emitStatus()
}
// emitStatus pushes the current index status to the frontend via Wails event.
// sameStatusAs reports whether two statuses would render identically.
// IndexStatus holds a slice, so it is not comparable with ==.
func (s IndexStatus) sameStatusAs(o IndexStatus) bool {
if s.Building != o.Building ||
s.Ready != o.Ready ||
s.LastBuilt != o.LastBuilt ||
s.Artists != o.Artists ||
s.Recordings != o.Recordings ||
s.ReleaseGroups != o.ReleaseGroups ||
s.TotalRows != o.TotalRows ||
len(s.Tiers) != len(o.Tiers) {
return false
}
for i := range s.Tiers {
if s.Tiers[i] != o.Tiers[i] {
return false
}
}
return true
}
// emitStatus pushes the current index status to the frontend via Wails
// event — but only when it differs from the last one pushed.
//
// The status is emitted from every path that touches it, several of
// which report progress in a tight loop, and the frontend's handler
// assigns to a @state field: an identical payload is therefore a full
// re-render of a 2 000-line template saying nothing. Deduplicating
// here rather than at the call sites means no future emitter has to
// remember (`perf.M6` / `H-14`).
func (si *SearchIndex) emitStatus() {
if si.runtimeCtx == nil {
return
@@ -689,6 +727,23 @@ func (si *SearchIndex) emitStatus() {
status.Building = si.cancel != nil
si.mu.RUnlock()
si.emitMu.Lock()
unchanged := si.lastEmitted != nil &&
si.lastEmitted.sameStatusAs(status)
if !unchanged {
snapshot := status
snapshot.Tiers = append(
[]TierStatus(nil), status.Tiers...,
)
si.lastEmitted = &snapshot
}
si.emitMu.Unlock()
if unchanged {
return
}
events.Emit(si.runtimeCtx, events.IndexStatusChanged, status)
// Mirror into the shared job registry. Every status mutation goes
@@ -2644,6 +2699,13 @@ func (si *SearchIndex) MarkReadyIfPopulated() {
si.logger.Info("search index: using existing index", "entries", count)
// Becoming ready is a change the UI has to see, and this was the one
// path that mutated the status without saying so — the 3 s ticker
// carried it, invisibly, which is why removing the ticker without
// this line would have left the settings page reading "not ready"
// over a fully built index.
si.emitStatus()
if !championBuilt {
si.scheduleChampionRebuild()
}