/**
 * Minimal tombstones (journal spec §1.7, NEW-2, R5-5; T12986, S3c).
 *
 * The sealer writes a FULL tombstone on D: the row meta with `deleted = 1`,
 * the delete HLC, the natural key and the before-image hash. GC never forgets
 * that a uid was deleted; once the stream is safely past a tombstone,
 * {@link compactTombstones} shrinks it to the minimal form
 * (`tbl`, `uid`, `hlc`, `deleted = 1`), so a receiver can still tell a
 * deleted uid from a never-seen one and a late op never resurrects the row.
 * It is found by its WITHOUT ROWID key and has no entry in the tombstone
 * index (which holds only full tombstones): about 155 B per row as measured,
 * within the spec's ~190 B.
 *
 * Append-only tables get no per-row tombstone at all (the sealer removes
 * their meta on D); the horizon fold into `_sync_tomb_fold` needs checkpoint
 * receive watermarks and is S4.
 *
 * What makes a tombstone compactable is stream state this slice does not own
 * (the latest verified checkpoint's `ReplicaHeads`, T12338; the inbox's
 * pending and void transactions, T12344), so the caller supplies it as a
 * {@link TombstoneGcPolicy}.
 *
 * @module store/sync/tombstones
 * @task T12986
 * @epic T12323
 */
import type { DatabaseSync } from 'node:sqlite';
/** Grace after a tombstone's physical time before it may be compacted (§1.7). */
export declare const TOMBSTONE_GRACE_MS: number;
/** When a full tombstone may shrink to its minimal form. */
export interface TombstoneGcPolicy {
    /**
     * The highest HLC every live replica has covered: in the latest verified
     * checkpoint's `ReplicaHeads`, each live replica's `lastReplicaSeq` covers a
     * segment whose `hlcMax` is at least this. Retired replicas are left out by
     * the caller (§1.5). Only tombstones at or below it are compacted.
     */
    readonly coveredHlc: string;
    /** Wall clock, ms. */
    readonly now: number;
    /** @defaultValue {@link TOMBSTONE_GRACE_MS} */
    readonly graceMs?: number;
    /**
     * Whether a `pending` or `void` inbox transaction references the uid
     * (T12344). Such a full tombstone is kept: the void may yet be revived.
     */
    readonly referenced: (tbl: string, uid: string) => boolean;
    /** Most tombstones examined per call. @defaultValue 5000 */
    readonly budget?: number;
}
/** What {@link compactTombstones} did. */
export interface TombstoneCompactReport {
    /** Full tombstones shrunk to the minimal form. */
    readonly compacted: number;
    /** Eligible by HLC and age, kept because an inbox transaction references the uid. */
    readonly referenced: number;
    /** Covered, but younger than the grace period. */
    readonly young: number;
}
/**
 * Shrink full tombstones the stream no longer needs to their minimal form,
 * in one `BEGIN IMMEDIATE`. Never deletes a tombstone: a minimal one is kept
 * for good (NEW-2).
 *
 * The minimal form keeps `tbl`, `uid`, `hlc` and `deleted = 1`; `origin` and
 * `version` take their empty values (`''`, `0`) because the columns are
 * NOT NULL, and `sent`, `held` and `fk_excluded` are left as they are.
 */
export declare function compactTombstones(db: DatabaseSync, policy: TombstoneGcPolicy): TombstoneCompactReport;
/** Tombstone counts for the doctor and the growth measurement (§1.7 R5-5). */
export declare function tombstoneCounts(db: DatabaseSync): {
    full: number;
    minimal: number;
};
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