replace Redis with an embedded SQLite string->string KV store (group commit, in-tx events, SQL search)
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This commit is contained in:
Worph
2026-10-19 20:51:00 +00:00
parent c53146e514
commit dc5cbdfb9b
80 changed files with 4601 additions and 6077 deletions
+33 -195
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@@ -1,221 +1,59 @@
package api
import (
"log"
"net/http"
"sort"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/metazla/meta-core/internal/storage"
)
// searchIndexRefreshInterval is how often the in-memory search index is rebuilt
// from Redis in the background. Records ingest continuously, so a newly stored
// record becomes searchable within one interval; the rebuild is a single
// batched bulk read (storage.GetSearchIndexTuples), off the request path.
const searchIndexRefreshInterval = 60 * time.Second
// searchIndexReconcileEvery is how many refresh ticks pass between full
// rebuilds. Every other tick is incremental. 30 ticks × 60 s = a full
// reconcile every 30 minutes — see runRefreshLoop for why one is kept at all.
const searchIndexReconcileEvery = 30
// searchIndex is an in-memory snapshot of every record's search haystack
// (hashID + lowercased searchable fields), kept current from Redis. It exists
// so POST /api/metadata/search matches in memory (string ops over a slice)
// instead of doing a SCAN+MGET Redis round-trip per record — the latter took
// 40s+ over ~72k records and made a live parallel search path unusable.
// serveIndexedSearch answers a search from the database's derived indexes
// (storage.Search): SQL narrows to a superset of candidates through the field
// expression index and the FTS5 trigram table, then every candidate is checked
// here with the exact matchers below — a token-AND match against the record's
// haystack (or a whole-query hashID substring, preserving the legacy
// behaviour) AND every structured filter.
//
// # Two update paths, and why
//
// `refresh` rebuilds everything: a whole-keyspace SCAN, batched MGETs, and a
// complete fresh copy. That is O(corpus) regardless of how much changed, and it
// used to run every 60 s forever. Measured on a 19 622-record staging corpus
// (2026-08-30): the loop accounted for ~45 % of ALL Redis CPU, and the Go side
// held 783 MB for data Redis stores in 135 MB — largely the double copy.
//
// `refreshIncremental` re-reads only the records that changed, tracked by
// storage's dirty set (search_dirty.go). Cost is O(change). It is the steady
// state; the full rebuild runs once at startup (there is nothing to be
// incremental against) and then only as an explicit repair.
//
// The distinction matters because meta-core is the platform's permanent,
// additive store — every search hit on every gateway is retained — so a rebuild
// priced against the whole corpus is a cost that only ever grows.
type searchIndex struct {
mu sync.RWMutex
// byID is the authoritative content; tuples is a stable-order view of it
// rebuilt on each update. Map iteration order in Go is randomised, so
// serving a limited query straight off the map would return a different
// subset each call — the slice is what keeps results stable.
byID map[string]storage.SearchTuple
tuples []storage.SearchTuple
ready atomic.Bool
}
// snapshot returns the current tuples slice and whether the index has built at
// least once. Every update swaps in a fresh slice under the write lock (never
// mutates in place), so the returned slice is safe to read lock-free.
func (idx *searchIndex) snapshot() ([]storage.SearchTuple, bool) {
idx.mu.RLock()
defer idx.mu.RUnlock()
return idx.tuples, idx.ready.Load()
}
// rebuildViewLocked regenerates the stable-order slice from byID. Caller holds
// the write lock.
func (idx *searchIndex) rebuildViewLocked() {
view := make([]storage.SearchTuple, 0, len(idx.byID))
for _, t := range idx.byID {
view = append(view, t)
}
// Stable across rebuilds so a limited query returns a consistent page
// rather than a fresh random subset every interval.
sort.Slice(view, func(i, j int) bool { return view[i].HashID < view[j].HashID })
idx.tuples = view
}
// refresh rebuilds the whole index from Redis (a batched bulk read). Used for
// the initial build and as an explicit repair — not the steady state.
func (idx *searchIndex) refresh(stor *storage.Client) {
if stor == nil || !stor.IsConnected() {
return
}
tuples, err := stor.GetSearchIndexTuples()
if err != nil {
log.Printf("[API] search index refresh failed: %v", err)
return
}
byID := make(map[string]storage.SearchTuple, len(tuples))
for _, t := range tuples {
byID[t.HashID] = t
}
idx.mu.Lock()
idx.byID = byID
idx.rebuildViewLocked()
idx.mu.Unlock()
idx.ready.Store(true)
}
// refreshIncremental drains the dirty set and patches only those records.
// Returns whether more dirty entries remain, so a burst is caught up over
// consecutive passes rather than one per interval.
//
// A record in the dirty set but absent from storage was deleted and is evicted
// here — otherwise it would keep answering searches until the next full
// rebuild. A batch that fails after the (destructive) drain is re-marked by
// storage so it is retried rather than silently lost.
func (idx *searchIndex) refreshIncremental(stor *storage.Client) (more bool) {
if stor == nil || !stor.IsConnected() {
return false
}
ids, more, err := stor.DrainDirty()
if err != nil {
log.Printf("[API] search index drain failed: %v", err)
return false
}
if len(ids) == 0 {
return false
}
tuples, gone, err := stor.GetSearchIndexTuplesFor(ids)
if err != nil {
stor.MarkDirty(ids...)
log.Printf("[API] incremental search index refresh failed: %v", err)
return false
}
idx.mu.Lock()
if idx.byID == nil {
idx.byID = make(map[string]storage.SearchTuple, len(tuples))
}
for _, t := range tuples {
idx.byID[t.HashID] = t
}
for _, id := range gone {
delete(idx.byID, id)
}
idx.rebuildViewLocked()
idx.mu.Unlock()
log.Printf("[API] search index: %d updated, %d evicted (%d records)", len(tuples), len(gone), len(idx.tuples))
return more
}
// runRefreshLoop builds the index once in full, then keeps it current from the
// dirty set, with a periodic full reconcile as a safety net.
//
// The reconcile exists because a *missed* dirty mark is silent: no error, just
// a record whose indexed copy quietly diverges from storage until something
// forces a rebuild. Marking is spread across eight write paths plus anything
// added later, and the cost of getting it wrong is invisible — so the index
// should not depend on that coverage being perfect forever. Every
// searchIndexReconcileEvery-th tick pays the old O(corpus) pass and repairs
// whatever drifted.
//
// That still drops the full rebuild from every 60 s to every 30 min — a ~30×
// reduction in the steady-state cost that measured at ~45 % of all Redis CPU —
// while keeping the self-healing property that made the naive loop safe.
func (idx *searchIndex) runRefreshLoop(stor *storage.Client) {
idx.refresh(stor)
ticker := time.NewTicker(searchIndexRefreshInterval)
defer ticker.Stop()
ticks := 0
for range ticker.C {
ticks++
if ticks%searchIndexReconcileEvery == 0 {
idx.refresh(stor)
continue
}
// Drain until caught up, so a burst larger than one batch does not take
// one interval per batch to land.
for idx.refreshIncremental(stor) {
}
}
}
// serveIndexedSearch answers a search from the in-memory index: a token-AND
// match against each record's haystack (or a whole-query hashID substring,
// preserving the legacy behaviour) AND every structured filter, then returns
// the full metadata for the <=limit survivors. No Redis round-trip per scanned
// record — matching and results both come from memory.
// Until 2026-10 this ran against an in-memory copy of every record, rebuilt
// from Redis; that copy cost ~30 KB of RAM per record (5.1 GB on watch.nsl.sh)
// and is gone. The matchers did not change, so neither did the semantics.
//
// This is the ONLY search path. Free text, filters, both, or neither all land
// here; only the `hashId` exact-match branch in handleSearchMetadata bypasses it.
func (s *Server) serveIndexedSearch(w http.ResponseWriter, req MetadataSearchRequest) {
tuples, ready := s.search.snapshot()
if !ready {
// First call before the background build finished: warm inline with the
// efficient batched read (seconds), never the per-record SCAN fallback.
s.search.refresh(s.storage)
tuples, _ = s.search.snapshot()
}
tokens := strings.Fields(strings.ToLower(req.Query))
queryLower := strings.ToLower(req.Query)
filters := normalizedFilters(req)
results := make([]MetadataSearchResult, 0, req.Limit)
for _, t := range tuples {
if len(results) >= req.Limit {
break
}
narrow := make([]storage.SearchFilter, 0, len(filters))
for _, f := range filters {
narrow = append(narrow, storage.SearchFilter{Property: f.Property, Values: f.Values})
}
hits, err := s.storage.Search(req.Query, narrow, req.Limit, func(hashID string, fields map[string]string) bool {
if req.Query != "" &&
!matchAllTokens(t.Haystack, tokens) &&
!strings.Contains(strings.ToLower(t.HashID), queryLower) {
continue
!matchAllTokens(storage.Haystack(fields), tokens) &&
!strings.Contains(strings.ToLower(hashID), queryLower) {
return false
}
if !recordMatchesFilters(t.Fields, filters) {
continue
}
// Full metadata is cached in the index — return it straight from memory,
// no Redis round-trip per result.
results = append(results, MetadataSearchResult{HashID: t.HashID, Metadata: t.Fields})
return recordMatchesFilters(fields, filters)
})
if err != nil {
writeError(w, http.StatusInternalServerError, "search failed: "+err.Error())
return
}
total, err := s.storage.CountRoots()
if err != nil {
total = 0
}
results := make([]MetadataSearchResult, 0, len(hits))
for _, h := range hits {
results = append(results, MetadataSearchResult{HashID: h.HashID, Metadata: h.Fields})
}
writeJSON(w, http.StatusOK, MetadataSearchResponse{
Results: results,
Count: len(results),
Total: len(tuples),
Total: int(total),
})
}