Language reference

NOW (current timestamp)

Syntax

NOW()

π id, NOW() → fetched_at (Records)

Description

NOW returns the current moment as a TIMESTAMP (in UTC). Use it to stamp results with the time they were produced, or to compute how long ago something happened relative to right now.

Technical Description

NOW() → TIMESTAMP. Returns the current instant (Instant.now(), UTC). Zero-argument. It reads system state, so it is neither PURE nor DETERMINISTIC — the optimizer never folds or dedupes it, and every evaluation reflects the call time.

Examples

Stamp each row with the fetch time:

π id, NOW() → fetched_at (Records)

PROJECT id, NOW() -> fetched_at (Records)

Records from the last hour:

σ created_at >= (NOW() - DURATION 'PT1H') (Events)

σ created_at ≥ (NOW() - DURATION 'PT1H') (Events)

SELECT created_at >= (NOW() - DURATION 'PT1H') (Events)

Age of each ticket:

π id, (NOW() - opened_at) → age (Tickets)

PROJECT id, (NOW() - opened_at) -> age (Tickets)

Pushdown

The call is never handed to a backend — a database asked to evaluate NOW() answers from its own clock, and the session's clock is what decides what "now" means here. The value is: the engine evaluates NOW() once for the run and sends the resulting TIMESTAMP literal, which a backend has no opinion about. So σ at < NOW() (conn.events) folds into a WHERE and filters at the source, with the session's instant in it.

Every current-time call in one run reads the same moment. That is what makes the substitution honest rather than convenient: the value sent to the database is the same value the rest of the query computes here, so a query half folded and half not still compares against one instant.

Reproducible runs (pinned clock)

By default NOW() reads the wall clock, so a query with a relative window returns different rows each time it runs — which makes a result impossible to reproduce later. Pass relix --now <ISO-8601 UTC instant> (or set RELIX_NOW) to pin NOW(), CURRENT_DATE() and CURRENT_TIME() to a fixed instant for the whole run:

relix --exec --now 2026-07-22T12:00:00Z report.relix

Every evaluation in that run then sees the same instant, so replaying the script over the same data yields byte-identical results however much later it runs. The functions stay non-PURE and non-DETERMINISTIC regardless — under the default clock they still advance, so the optimizer must never fold or dedupe them.

Limitations

Non-deterministic (reads the clock); not folded by the optimizer. Always UTC.

Alternatives

CURRENT_DATE for today's date only; CURRENT_TIME for the clock time only.