Limits

Every script run has a budget. Running out fails the run with an error a script can’t catch.

Limit	Default	Applies to	Configurable
Instructions	1,000,000 per run	Queries, procedures, record and label scripts	Yes, 1,000 to 1,000,000,000
Wall clock	10 seconds per run	Queries, procedures, record and label scripts	Yes, 1 to 300 seconds
Memory	64 MiB per run	Every script type, jobs included	No
Stack (JavaScript and TypeScript)	384 KiB	Every script type	No

Jobs have no instruction limit and no wall clock, because running long is what a job is for. A job should check ctx.job.should_stop() and return when it is asked to stop.

Instructions

The instruction limit stops runaway loops. What counts as one instruction depends on the language:

Lua counts Lua VM instructions.
JavaScript and TypeScript count the engine’s interrupt checks, which happen at every loop back-edge and function call.

So the same setting allows a different amount of work in each language.

Once the budget is spent it stays spent. In Lua, pcall, xpcall and coroutine.resume re-raise it. In JavaScript and TypeScript the interrupt skips catch and finally. A run that spends its budget fails with timeout.

For TypeScript, the compile step that turns your script into JavaScript runs before the engine starts, so the instruction budget doesn’t count it. The wall clock and the host’s memory ceiling still do.

Wall clock

The wall clock counts only time the script itself is running. Time spent waiting on the host, such as an HTTP request or a database read, is not charged. A run that hits the wall clock fails with timeout. In a JavaScript or TypeScript script, library calls still in flight when the run is cut short are dropped with it.

Memory

Each run may allocate up to 64 MiB. The interpreter enforces this, so running out is a normal script error with errorType memory. Above that, the host holds the plugin to twice that amount as a backstop for anything the interpreter can’t see.

Stack

In JavaScript and TypeScript, runaway recursion throws RangeError: Maximum call stack size exceeded, which a script can catch.

What a client sees

For a query or procedure:

Cause	`errorType`	Status
Instruction limit or wall clock	`timeout`	408
Memory	`memory`	500

For a record or label script, the failure is retried and then dead-lettered. For a job, the job fails. See failures and retries.

Change the limits

Set the instruction limit and wall clock in the dashboard under System > General, in the Instruction limit and Request wall clock (seconds) fields. You can also set them with environment variables:

SCRIPT_INSTRUCTION_LIMIT=5000000
SCRIPT_WALL_CLOCK_SECONDS=30

Each value is read from the dashboard setting first, then the environment variable, then the default. A value outside the allowed range is refused when you save it in the dashboard. An environment value outside the range is logged as a warning and the default is used. A change reaches other instances that share the database within 10 seconds.

Other caps

A job.wait(seconds) call is clamped to between 0 and 3600 seconds.
A record query through happyview.db returns 20 records by default and at most 100 per page. Paginate with the cursor for more.
A script description can be up to 300 characters.
A test file run by happyview test may spend up to 60 seconds of its own time, outside the triggers it fires.