Function materialize

apps/sim/lib/table/snapshot-cache.ts:92–129

* Streams the table CSV (keyset-paginated, like the export worker) into storage under `key`, * aborting if it crosses SNAPSHOT_MAX_BYTES. Returns the stored byte size. Bytes match the * canonical export format (id-keyed reads, display-name headers).

(table: TableDefinition, key: string)

 * canonical export format (id-keyed reads, display-name headers).
 */
async function materialize(table: TableDefinition, key: string): Promise<number> {
  const columns = table.schema.columns
  const handle = await createMultipartUpload({
    key,
    context: SNAPSHOT_STORAGE_CONTEXT,
    contentType: SNAPSHOT_CONTENT_TYPE,
  })

  try {
    let bytes = 0
    const header = `${toCsvRow(columns.map((c) => neutralizeCsvFormula(c.name)))}\n`
    bytes += Buffer.byteLength(header)
    await handle.write(header)

    let after: { orderKey: string; id: string } | null = null
    while (true) {
      const page = await selectExportRowPage(table, after, SNAPSHOT_BATCH_SIZE)
      if (page.length === 0) break

      const chunk = page
        .map((row) => `${toCsvRow(columns.map((c) => formatCsvValue(row.data[getColumnId(c)])))}\n`)
        .join('')
      bytes += Buffer.byteLength(chunk)
      if (bytes > SNAPSHOT_MAX_BYTES) throw new TableSnapshotTooLargeError(table.id)
      await handle.write(chunk)

      const last = page[page.length - 1]
      after = { orderKey: last.orderKey, id: last.id }
      if (page.length < SNAPSHOT_BATCH_SIZE) break
    }

    const { size } = await handle.complete()
    return size
  } catch (err) {
    await handle.abort().catch(() => {})
    throw err
  }
}

/** Best-effort removal of the immediately-prior version (the common single-mutation case). */
async function deletePreviousVersion(