BigQuery - 等待 UDF function 和 JavaScript 代码

Question

In Bigquery does not exist a native function like DBMS_LOCK.SLEEP (or DBMS_SESSION.SLEEP) from Oracle ("Puts a procedure to sleep for a specific time"). I tried to use an UDF with JavaScript code but it does not work as I expect: it does not stop other than forced. Can you help me understand what's going on? Thanks!

CREATE TEMP FUNCTION JS_Sleep(x FLOAT64)
 RETURNS FLOAT64
LANGUAGE js AS r"""
  function sleep(milliseconds) {
    const date = Date.now();
    let currentDate = null;
    do {
      currentDate = Date.now();
    } while (currentDate - date < milliseconds);
  }
  return sleep(x);

  """;
select JS_Sleep(10000);

Answer 1

In BigQuery, CURRENT_TIMESTAMP() similar with Date.now() always returns same value in a single statement or in a single transaction as if time stops regardless how many it appears in a query.

In my experience, this also applies to Date.now(). In your case, JS_Sleep() runs forever cause time stops within your query.