feat(sync): a stable identity per contact, indexed
Two PCs exchanging changes through a folder must be able to name the SAME contact in both logs. "the QSO with M0ABC at 14:32" is a guess and the two machines can disagree about which row that is, so an edit or a deletion cannot be addressed at all without an identity that travels with the record. A real indexed column, not a key inside extras_json: the identity is resolved once per incoming change, and scanning JSON for it would turn every sync into a full read of a 120 000-QSO logbook. A column costs one migration; the JSON would cost a scan every time. That was the decision to confirm, and it is confirmed. It follows the award_refs pattern — read in selectCols, absent from columnList, written only through its own methods. So an ordinary edit cannot clobber it, which matters: another machine addresses the contact by that id, and losing it makes the same QSO arrive again as a new one. Pinned by a test that saves an edit with the field deliberately blanked. Existing contacts are stamped in batches inside one transaction rather than one commit each — on a remote MySQL the round trip dominates, and 120 000 commits is the difference between a minute and an afternoon. And a dedupe-key map lets two machines that already hold the same imported log recognise each other's contacts instead of copying 120 000 of them across. MySQL nearly lost its logbook to this. It cannot index a TEXT column without a prefix length: the migration would fail with error 1170 and fail again on every startup, with no way out from the interface. The translator only emits VARCHAR for names listed by hand in varcharColumns. sync_uid is now listed — and a test reads the migrations, works out which indexed columns are TEXT, and fails if the list does not cover them, so the next one cannot reach a shared logbook.
This commit is contained in:
+138
-2
@@ -215,6 +215,12 @@ type QSO struct {
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// that doesn't know about it can't clobber it.
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AwardRefs string `json:"award_refs,omitempty"`
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// SyncUID is this contact's stable identity for folder synchronisation —
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// what lets another machine name the same QSO when it edits or deletes it.
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// Like AwardRefs it is read here but NOT in columnList, so an ordinary edit
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// can never clobber it; it is written only by SetSyncUID / BackfillSyncUIDs.
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SyncUID string `json:"sync_uid,omitempty"`
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CreatedAt time.Time `json:"created_at"`
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UpdatedAt time.Time `json:"updated_at"`
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}
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@@ -271,7 +277,7 @@ const columnList = `callsign, qso_date, qso_date_off, band, band_rx, mode, submo
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// award_refs is read here but is NOT part of columnList (the insert/update
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// write path) — it is a derived cache written only via SetAwardRefs, so a
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// normal QSO write can never clobber it.
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const selectCols = `id, ` + columnList + `, award_refs, created_at, updated_at`
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const selectCols = `id, ` + columnList + `, award_refs, sync_uid, created_at, updated_at`
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// columnCount is derived from columnList at init so they can never drift.
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var columnCount = countColumns(columnList)
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@@ -3076,6 +3082,7 @@ func scanQSO(s scanner) (QSO, error) {
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myARRLSect, myVUCCGrids sql.NullString
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extrasJSON sql.NullString
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awardRefs sql.NullString
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syncUID sql.NullString
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createdStr, updatedStr string
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)
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if err := s.Scan(
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@@ -3103,7 +3110,7 @@ func scanQSO(s scanner) (QSO, error) {
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&skcc, &fists, &tenTen, &contactedOp, &eqCall, &pfx, &myName, &class,
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&darcDOK, &myDarcDOK, ®ion, &silentKey, &swl, &qsoComplete, &qsoRandom,
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&creditGranted, &creditSubmitted, &myARRLSect, &myVUCCGrids,
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&extrasJSON, &awardRefs, &createdStr, &updatedStr,
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&extrasJSON, &awardRefs, &syncUID, &createdStr, &updatedStr,
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); err != nil {
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return QSO{}, fmt.Errorf("scan qso: %w", err)
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}
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@@ -3303,6 +3310,7 @@ func scanQSO(s scanner) (QSO, error) {
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q.MyVUCCGrids = myVUCCGrids.String
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q.Extras = decodeExtras(extrasJSON.String)
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q.AwardRefs = awardRefs.String
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q.SyncUID = syncUID.String
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return q, nil
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}
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@@ -3413,3 +3421,131 @@ func (r *Repo) OrderedIDs(ctx context.Context) ([]int64, time.Time, error) {
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// Parsed once, for the newest row only — the ordering came from SQL.
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return out, parseTimeLoose(lastDate), nil
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}
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// --- Folder synchronisation identity -----------------------------------------
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// SetSyncUID stamps a contact's sync identity. Targeted UPDATE: it must never
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// go through the normal write path, or an ordinary edit would clobber it.
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func (r *Repo) SetSyncUID(ctx context.Context, id int64, uid string) error {
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_, err := r.db.ExecContext(ctx, `UPDATE qso SET sync_uid = ? WHERE id = ?`, uid, id)
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return err
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}
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// IDBySyncUID resolves an incoming change to a local row. Indexed, so this is
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// the one lookup a sync performs per record and it stays a key hit rather than
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// a scan — which is the whole reason sync_uid is a column and not a JSON key.
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func (r *Repo) IDBySyncUID(ctx context.Context, uid string) (int64, bool, error) {
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if uid == "" {
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return 0, false, nil
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}
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var id int64
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err := r.db.QueryRowContext(ctx, `SELECT id FROM qso WHERE sync_uid = ? LIMIT 1`, uid).Scan(&id)
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if err == sql.ErrNoRows {
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return 0, false, nil
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}
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if err != nil {
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return 0, false, err
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}
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return id, true, nil
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}
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// CountWithoutSyncUID reports how many contacts still have no identity — what
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// the settings panel shows before the first synchronisation.
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func (r *Repo) CountWithoutSyncUID(ctx context.Context) (int64, error) {
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var n int64
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err := r.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM qso WHERE sync_uid = '' OR sync_uid IS NULL`).Scan(&n)
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return n, err
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}
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// NeedSyncUID returns the ids of contacts still without an identity, at most
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// limit of them.
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//
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// Batched rather than "all of them": a 120 000-QSO logbook is given its
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// identities a few thousand at a time, so the first synchronisation cannot hold
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// the database — or the interface — for however long a single enormous
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// transaction would take on a remote MySQL.
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func (r *Repo) NeedSyncUID(ctx context.Context, limit int) ([]int64, error) {
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if limit <= 0 {
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limit = 2000
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}
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rows, err := r.db.QueryContext(ctx,
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`SELECT id FROM qso WHERE sync_uid = '' OR sync_uid IS NULL ORDER BY id LIMIT ?`, limit)
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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var out []int64
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for rows.Next() {
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var id int64
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if err := rows.Scan(&id); err != nil {
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return nil, err
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}
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out = append(out, id)
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}
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return out, rows.Err()
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}
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// AssignSyncUIDs stamps a batch of identities in ONE transaction.
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//
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// One statement per row inside a single transaction, not one transaction per
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// row: on a remote MySQL the round trip dominates, and 120 000 separate commits
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// is the difference between a minute and an afternoon.
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func (r *Repo) AssignSyncUIDs(ctx context.Context, uids map[int64]string) error {
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if len(uids) == 0 {
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return nil
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}
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tx, err := r.db.BeginTx(ctx, nil)
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if err != nil {
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return err
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}
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defer tx.Rollback()
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stmt, err := tx.PrepareContext(ctx, `UPDATE qso SET sync_uid = ? WHERE id = ? AND (sync_uid = '' OR sync_uid IS NULL)`)
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if err != nil {
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return err
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}
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defer stmt.Close()
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for id, uid := range uids {
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if _, err := stmt.ExecContext(ctx, uid, id); err != nil {
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return err
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}
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}
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return tx.Commit()
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}
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// SyncUIDByDedupeKey maps every contact's dedupe key to its sync identity.
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//
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// This is what stops two machines that already hold the SAME imported log from
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// copying it to each other: an incoming contact whose identity is unknown but
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// whose key matches one here is the same contact, and it adopts the incoming
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// identity instead of being inserted a second time.
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//
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// One scan of four short columns, done once per synchronisation pass — the same
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// shape as the importer's own dedupe load, which is the cheapest read in the
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// repo.
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func (r *Repo) SyncUIDByDedupeKey(ctx context.Context) (map[string]struct {
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ID int64
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UID string
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}, error) {
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rows, err := r.db.QueryContext(ctx, `
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SELECT id, sync_uid, callsign, substr(qso_date, 1, 16), band, mode FROM qso`)
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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out := make(map[string]struct {
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ID int64
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UID string
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}, 1024)
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for rows.Next() {
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var id int64
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var uid, call, when, band, mode sql.NullString
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if err := rows.Scan(&id, &uid, &call, &when, &band, &mode); err != nil {
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return nil, err
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}
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out[DedupeKey(call.String, when.String, band.String, mode.String)] = struct {
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ID int64
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UID string
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}{ID: id, UID: uid.String}
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}
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return out, rows.Err()
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}
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