Function/Benchmark: fasterToLocalString

Enterprise Edition

Goal: Explore faster local time zone date formating.

This function fasterToLocalString demonstrates a faster alternative to the built-in JavaScript function toLocalString.
As of Couchbase 6.6.0 the fasterToLocalString implementation is 708X faster. This demonstrates that all date conversion should be benchmarked.
Requires a metadata bucket, a source bucket.
Will operate on any mutation where doc.type === "basic_bkt_ops".
Deploy from now
Only mutate one document as this is a benchmark of ICU performance.

fasterToLocalString
Input Data/Mutation
Output Data/Logged

// To run need a Binding in this Function's Settings as follows:
// 1. Deploy from now
// 2. Mutate one document in the source bucket
// 3. Inspect the log files
function fasterToLocalString(d) {
    // adjust the input date by the UTC offset
    var dadj = new Date(d.getTime() - d.getTimezoneOffset() * 60 * 1000);
    var hr = dadj.getUTCHours();
    var min = dadj.getUTCMinutes();
    var sec = dadj.getUTCSeconds();
    var strLocalDate = (dadj.getUTCMonth()+1) + "/" + dadj.getUTCDate() + "/" + dadj.getUTCFullYear() + ", " +
        ((hr < 13) ? hr : (hr - 12)) + ":" +
        ((min<10) ? "0"+min : min) + ":" +
        ((sec<10) ? "0"+sec : sec) +
        ((hr < 12) ? " AM" : " PM");
    // should be the same as d.toLocaleString('en-US')
    return strLocalDate;
}

function OnUpdate(doc, meta) {
    var cnt = 20000;
    var d = new Date();
    var tbeg, tend;

    if (true) {
        // This crash a debug session refer to eventing-debugging-and-diagnosability.html
        // however it always work in no-debug but is very slow.
        tbeg = Date.now();
        for (var i=1; i<=cnt; i++) {
            var res = d.toLocaleString('en-US');
            if (i % cnt == 0)
                log("d.toLocaleString('en-US') ",res);
        }
        tend = Date.now();
        log("d.toLocaleString('en-US') ", tend-tbeg + " ms.");
    }

    if (true) {
        tbeg = Date.now();
        for (var i=1; i<=cnt; i++) {
            var res = fasterToLocalString(d);
            if (i % cnt == 0)
                log("fasterToLocalString(d)   ",res);
        }
        tend = Date.now();
        log("fasterToLocalString(d)   ", tend-tbeg + " ms.");
    }
}

Create/Mutate any single document in the source bucket

This below messages are from the Application log in the file system (the UI would display the messages in reverse order)

2020-09-16T18:40:48.430-07:00 [INFO] "d.toLocaleString('en-US') " "9/16/2020, 6:40:32 PM"
2020-09-16T18:40:48.430-07:00 [INFO] "d.toLocaleString('en-US') " "16299 ms."
2020-09-16T18:40:48.453-07:00 [INFO] "fasterToLocalString(d)   " "9/16/2020, 6:40:32 PM"
2020-09-16T18:40:48.453-07:00 [INFO] "fasterToLocalString(d)   " "23 ms."

The above was run on a single Eventing node 12 cores at 2.2 GHz, shows that the v8 runner is not performant for the built-in function toLocaleString. We can use fasterToLocalString and do 708 more conversions in the same amount of time.