Function resolveWalValveMb

src/db/wal-valve.ts:64–78

(envVal: string | undefined, dbSizeBytes?: number)

 * override; non-numeric / non-positive values fall back to the default.
 */
export function resolveWalValveMb(envVal: string | undefined, dbSizeBytes?: number): number {
  if (envVal !== undefined && envVal !== '') {
    const n = Number(envVal);
    if (Number.isFinite(n) && n > 0) return Math.floor(n);
  }
  // Scale with the project when the caller knows the DB size: every fold
  // re-writes hot B-tree pages into the main file (the #1231 pathology in
  // bounded form — 111s of a kernel-scale batch loop at the flat 256MB cap,
  // §7a.2), so a big project affords a proportionally bigger transient WAL
  // (~dbSize/4 soft ⇒ file cap ≈ dbSize) in exchange for ~4× fewer folds.
  if (dbSizeBytes !== undefined && dbSizeBytes > 0) {
    return Math.min(2048, Math.max(DEFAULT_WAL_VALVE_MB, Math.floor(dbSizeBytes / 4 / (1024 * 1024))));
  }
  return DEFAULT_WAL_VALVE_MB;
}

export class WalCheckpointValve {
  private timer: ReturnType<typeof setInterval> | null = null;