Deprecte Rounding#round

This deprecates `Rounding#round` and `Rounding#nextRoundingValue` in
favor of calling
```
Rounding.Prepared prepared = rounding.prepare(min, max);
...
prepared.round(val)

``` because it is always going to be faster to prepare once. There
are going to be some cases where we won't know what to prepare *for*
and in those cases you can call `prepareForUnknown` and stil be faster
than calling the deprecated method over and over and over again.

Ultimately, this is important because it doesn't look like there is an
easy way to cache `Rounding.Prepared` or any of its precursors like
`LocalTimeOffset.Lookup`. Instead, we can just build it at most once per
request.

Relates to elastic#56124

server/src/main/java/org/elasticsearch/common/Rounding.java

@@ -240,9 +240,9 @@ public interface Prepared {
 
     /**
      * Rounds the given value.
-     * <p>
-     * Prefer {@link #prepare(long, long)} if rounding many values.
+     * @deprecated Prefer {@link #prepare} and then {@link Prepared#round(long)}
      */
+    @Deprecated
     public final long round(long utcMillis) {
         return prepare(utcMillis, utcMillis).round(utcMillis);
     }
@@ -252,9 +252,9 @@ public final long round(long utcMillis) {
      * {@link #round(long)}, returns the next rounding value. For
      * example, with interval based rounding, if the interval is
      * 3, {@code nextRoundValue(6) = 9}.
-     * <p>
-     * Prefer {@link #prepare(long, long)} if rounding many values.
+     * @deprecated Prefer {@link #prepare} and then {@link Prepared#nextRoundingValue(long)}
      */
+    @Deprecated
     public final long nextRoundingValue(long utcMillis) {
         return prepare(utcMillis, utcMillis).nextRoundingValue(utcMillis);
     }

server/src/test/java/org/elasticsearch/common/rounding/RoundingDuelTests.java

@@ -35,16 +35,16 @@ public class RoundingDuelTests extends ESTestCase  {
     public void testDuellingImplementations() {
         org.elasticsearch.common.Rounding.DateTimeUnit randomDateTimeUnit =
             randomFrom(org.elasticsearch.common.Rounding.DateTimeUnit.values());
-        org.elasticsearch.common.Rounding rounding;
+        org.elasticsearch.common.Rounding.Prepared rounding;
         Rounding roundingJoda;
 
         if (randomBoolean()) {
-            rounding = org.elasticsearch.common.Rounding.builder(randomDateTimeUnit).timeZone(ZoneOffset.UTC).build();
+            rounding = org.elasticsearch.common.Rounding.builder(randomDateTimeUnit).timeZone(ZoneOffset.UTC).build().prepareForUnknown();
             DateTimeUnit dateTimeUnit = DateTimeUnit.resolve(randomDateTimeUnit.getId());
             roundingJoda = Rounding.builder(dateTimeUnit).timeZone(DateTimeZone.UTC).build();
         } else {
             TimeValue interval = timeValue();
-            rounding = org.elasticsearch.common.Rounding.builder(interval).timeZone(ZoneOffset.UTC).build();
+            rounding = org.elasticsearch.common.Rounding.builder(interval).timeZone(ZoneOffset.UTC).build().prepareForUnknown();
             roundingJoda = Rounding.builder(interval).timeZone(DateTimeZone.UTC).build();
         }
 

server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java

@@ -157,6 +157,7 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
 
         int roundingIndex = reduced.getBucketInfo().roundingIdx;
         RoundingInfo roundingInfo = AutoDateHistogramAggregationBuilder.buildRoundings(null, null)[roundingIndex];
+        Rounding.Prepared prepared = roundingInfo.rounding.prepare(lowest, highest);
 
         long normalizedDuration = (highest - lowest) / roundingInfo.getRoughEstimateDurationMillis();
         int innerIntervalIndex = 0;
@@ -185,7 +186,7 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
         } else {
             do {
                 innerIntervalToUse = roundingInfo.innerIntervals[innerIntervalIndex];
-                int bucketCountAtInterval = getBucketCount(lowest, highest, roundingInfo.rounding, innerIntervalToUse);
+                int bucketCountAtInterval = getBucketCount(lowest, highest, prepared, innerIntervalToUse);
                 if (bucketCountAtInterval == reduced.getBuckets().size()) {
                     break;
                 }
@@ -199,11 +200,11 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
         assertThat(reduced.getInterval().toString(), equalTo(innerIntervalToUse + roundingInfo.unitAbbreviation));
         Map<Instant, Long> expectedCounts = new TreeMap<>();
         if (totalBucketConut > 0) {
-            long keyForBucket = roundingInfo.rounding.round(lowest);
-            while (keyForBucket <= roundingInfo.rounding.round(highest)) {
+            long keyForBucket = prepared.round(lowest);
+            while (keyForBucket <= prepared.round(highest)) {
                 long nextKey = keyForBucket;
                 for (int i = 0; i < innerIntervalToUse; i++) {
-                    nextKey = roundingInfo.rounding.nextRoundingValue(nextKey);
+                    nextKey = prepared.nextRoundingValue(nextKey);
                 }
                 Instant key = Instant.ofEpochMilli(keyForBucket);
                 expectedCounts.put(key, 0L);
@@ -214,7 +215,7 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
 
                 for (InternalAutoDateHistogram histogram : inputs) {
                     for (Histogram.Bucket bucket : histogram.getBuckets()) {
-                        long roundedBucketKey = roundingInfo.rounding.round(((ZonedDateTime) bucket.getKey()).toInstant().toEpochMilli());
+                        long roundedBucketKey = prepared.round(((ZonedDateTime) bucket.getKey()).toInstant().toEpochMilli());
                         long docCount = bucket.getDocCount();
                         if (roundedBucketKey >= keyForBucket && roundedBucketKey < nextKey) {
                             expectedCounts.compute(key,
@@ -227,8 +228,8 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
 
             // If there is only a single bucket, and we haven't added it above, add a bucket with no documents.
             // this step is necessary because of the roundedBucketKey < keyForBucket + intervalInMillis above.
-            if (roundingInfo.rounding.round(lowest) == roundingInfo.rounding.round(highest) && expectedCounts.isEmpty()) {
-                expectedCounts.put(Instant.ofEpochMilli(roundingInfo.rounding.round(lowest)), 0L);
+            if (prepared.round(lowest) == prepared.round(highest) && expectedCounts.isEmpty()) {
+                expectedCounts.put(Instant.ofEpochMilli(prepared.round(lowest)), 0L);
             }
         }
 
@@ -249,12 +250,12 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
         assertThat(reduced.getInterval(), equalTo(expectedInterval));
     }
 
-    private int getBucketCount(long min, long max, Rounding rounding, int interval) {
+    private int getBucketCount(long min, long max, Rounding.Prepared prepared, int interval) {
         int bucketCount = 0;
-        long key = rounding.round(min);
+        long key = prepared.round(min);
         while (key < max) {
             for (int i = 0; i < interval; i++) {
-                key = rounding.nextRoundingValue(key);
+                key = prepared.nextRoundingValue(key);
             }
             bucketCount++;
         }

server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java

@@ -58,7 +58,8 @@ public void setUp() throws Exception {
         long interval = randomIntBetween(1, 3);
         intervalMillis = randomFrom(timeValueSeconds(interval), timeValueMinutes(interval), timeValueHours(interval)).getMillis();
         Rounding rounding = Rounding.builder(TimeValue.timeValueMillis(intervalMillis)).build();
-        baseMillis = rounding.round(System.currentTimeMillis());
+        long now = System.currentTimeMillis();
+        baseMillis = rounding.prepare(now, now).round(now);
         if (randomBoolean()) {
             minDocCount = randomIntBetween(1, 10);
             emptyBucketInfo = null;
@@ -108,8 +109,12 @@ protected void assertReduced(InternalDateHistogram reduced, List<InternalDateHis
             long minBound = -1;
             long maxBound = -1;
             if (emptyBucketInfo.bounds != null) {
-                minBound = emptyBucketInfo.rounding.round(emptyBucketInfo.bounds.getMin());
-                maxBound = emptyBucketInfo.rounding.round(emptyBucketInfo.bounds.getMax());
+                Rounding.Prepared prepared = emptyBucketInfo.rounding.prepare(
+                    emptyBucketInfo.bounds.getMin(),
+                    emptyBucketInfo.bounds.getMax()
+                );
+                minBound = prepared.round(emptyBucketInfo.bounds.getMin());
+                maxBound = prepared.round(emptyBucketInfo.bounds.getMax());
                 if (expectedCounts.isEmpty() && minBound <= maxBound) {
                     expectedCounts.put(minBound, 0L);
                 }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/rollup/job/DateHistogramGroupConfig.java

@@ -304,7 +304,7 @@ public String getTimeZone() {
     /**
      * Create the rounding for this date histogram
      */
-    public Rounding createRounding() {
+    public Rounding.Prepared createRounding() {
         return createRounding(interval.toString(), timeZone);
     }
 
@@ -363,7 +363,7 @@ public static DateHistogramGroupConfig fromXContent(final XContentParser parser)
         return PARSER.parse(parser, null);
     }
 
-    private static Rounding createRounding(final String expr, final String timeZone) {
+    private static Rounding.Prepared createRounding(final String expr, final String timeZone) {
         Rounding.DateTimeUnit timeUnit = DateHistogramAggregationBuilder.DATE_FIELD_UNITS.get(expr);
         final Rounding.Builder rounding;
         if (timeUnit != null) {
@@ -372,6 +372,6 @@ private static Rounding createRounding(final String expr, final String timeZone)
             rounding = new Rounding.Builder(TimeValue.parseTimeValue(expr, "createRounding"));
         }
         rounding.timeZone(ZoneId.of(timeZone, ZoneId.SHORT_IDS));
-        return rounding.build();
+        return rounding.build().prepareForUnknown();
     }
 }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/pivot/DateHistogramGroupSource.java

@@ -209,13 +209,27 @@ private void writeInterval(Interval interval, StreamOutput out) throws IOExcepti
 
     private final Interval interval;
     private final ZoneId timeZone;
-    private Rounding rounding;
+    private final Rounding.Prepared rounding;
 
     public DateHistogramGroupSource(String field, ScriptConfig scriptConfig, Interval interval, ZoneId timeZone) {
         super(field, scriptConfig);
         this.interval = interval;
         this.timeZone = timeZone;
+        rounding = buildRounding();
+    }
+
+    public DateHistogramGroupSource(StreamInput in) throws IOException {
+        super(in);
+        this.interval = readInterval(in);
+        this.timeZone = in.readOptionalZoneId();
+        // Format was optional in 7.2.x, removed in 7.3+
+        if (in.getVersion().before(Version.V_7_3_0)) {
+            in.readOptionalString();
+        }
+        rounding = buildRounding();
+    }
 
+    private Rounding.Prepared buildRounding() {
         Rounding.DateTimeUnit timeUnit = DateHistogramAggregationBuilder.DATE_FIELD_UNITS.get(interval.toString());
         final Rounding.Builder roundingBuilder;
         if (timeUnit != null) {
@@ -227,17 +241,7 @@ public DateHistogramGroupSource(String field, ScriptConfig scriptConfig, Interva
         if (timeZone != null) {
             roundingBuilder.timeZone(timeZone);
         }
-        this.rounding = roundingBuilder.build();
-    }
-
-    public DateHistogramGroupSource(StreamInput in) throws IOException {
-        super(in);
-        this.interval = readInterval(in);
-        this.timeZone = in.readOptionalZoneId();
-        // Format was optional in 7.2.x, removed in 7.3+
-        if (in.getVersion().before(Version.V_7_3_0)) {
-            in.readOptionalString();
-        }
+        return roundingBuilder.build().prepareForUnknown();
     }
 
     private static ConstructingObjectParser<DateHistogramGroupSource, Void> createParser(boolean lenient) {
@@ -296,7 +300,7 @@ public ZoneId getTimeZone() {
         return timeZone;
     }
 
-    public Rounding getRounding() {
+    Rounding.Prepared getRounding() {
         return rounding;
     }
 

x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/job/RollupIndexerIndexingTests.java

@@ -274,7 +274,7 @@ public void testSimpleDateHistoWithDelay() throws Exception {
                         asMap("the_histo", now)
                 )
         );
-        final Rounding rounding = dateHistoConfig.createRounding();
+        final Rounding.Prepared rounding = dateHistoConfig.createRounding();
         executeTestCase(dataset, job, now, (resp) -> {
             assertThat(resp.size(), equalTo(3));
             IndexRequest request = resp.get(0);
@@ -338,7 +338,7 @@ public void testSimpleDateHistoWithOverlappingDelay() throws Exception {
                 asMap("the_histo", now)
             )
         );
-        final Rounding rounding = dateHistoConfig.createRounding();
+        final Rounding.Prepared rounding = dateHistoConfig.createRounding();
         executeTestCase(dataset, job, now, (resp) -> {
             assertThat(resp.size(), equalTo(2));
             IndexRequest request = resp.get(0);