#957 Implement earliest and latest functions

docs/ppl-lang/PPL-Example-Commands.md

@@ -499,9 +499,23 @@ _- **Limitation: another command usage of (relation) subquery is in `appendcols`
 -  `source = table | eval cdate = CAST('2012-08-07' as date), ctime = cast('2012-08-07T08:07:06' as timestamp) | fields cdate, ctime`
 -  `source = table | eval chained_cast = cast(cast("true" as boolean) as integer) | fields chained_cast`
 
+### **Relative Time Functions**
+
 #### **relative_timestamp**
-[See additional function details](functions/ppl-datetime#RELATIVE_TIMESTAMP)
+[See additional function details](functions/ppl-datetime#relative_timestamp)
 - `source = table | eval one_hour_ago = relative_timestamp("-1h") | where timestamp < one_hour_ago`
 - `source = table | eval start_of_today = relative_timestamp("@d") | where timestamp > start_of_today`
 - `source = table | eval last_saturday = relative_timestamp("-1d@w6") | where timestamp >= last_saturday`
+
+#### **earliest**
+[See additional function details](functions/ppl-datetime#earliest)
+- `source = table | where earliest("-1wk", timestamp)`
+- `source = table | where earliest("@qtr", timestamp)`
+- `source = table | where earliest("-2y@q", timestamp)`
+
+#### **latest**
+[See additional function details](functions/ppl-datetime#latest)
+- `source = table | where latest("-60m", timestamp)`
+- `source = table | where latest("@year", timestamp)`
+- `source = table | where latest("-day@w1", timestamp)`
 ---

docs/ppl-lang/functions/ppl-datetime.md

@@ -397,6 +397,44 @@ Example:
     +-------------------------------+
 
 
+### `EARLIEST`
+
+**Description:**
+
+**Usage:** earliest(string, timestamp) returns whether the timestamp defined by the given relative string is earlier
+than or at the same time as the specified timestamp.
+
+Argument type: STRING, TIMESTAMP
+
+Return type: BOOLEAN
+
+Example:
+
+    os> source=people | eval earliest = earliest("-1s", now()) | fields earliest | head 1
+    fetched rows / total rows = 1/1
+    +----------+
+    | earliest |
+    |----------|
+    | True     |
+    +----------+
+
+    os> source=people | eval earliest = earliest("now", now()) | fields earliest | head 1
+    fetched rows / total rows = 1/1
+    +----------+
+    | earliest |
+    |----------|
+    | True     |
+    +----------+
+
+    os> source=people | eval earliest = earliest("+1s", now()) | fields earliest | head 1
+    fetched rows / total rows = 1/1
+    +----------+
+    | earliest |
+    |----------|
+    | False    |
+    +----------+
+
+
 ### `FROM_UNIXTIME`
 
 **Description:**
@@ -507,6 +545,44 @@ Example:
     +--------------------------+
 
 
+### `LATEST`
+
+**Description:**
+
+**Usage:** latest(string, timestamp) returns whether the timestamp defined by the given relative string is later
+than or at the same time as the specified timestamp. See [relative_timestamp](#relative_timestamp) for more details.
+
+Argument type: STRING, TIMESTAMP
+
+Return type: BOOLEAN
+
+Example:
+
+    os> source=people | eval latest = latest("-1s", now()) | fields latest | head 1
+    fetched rows / total rows = 1/1
+    +--------+
+    | latest |
+    |--------|
+    | False  |
+    +--------+
+
+    os> source=people | eval latest = latest("now", now()) | fields latest | head 1
+    fetched rows / total rows = 1/1
+    +--------+
+    | latest |
+    |--------|
+    | True   |
+    +--------+
+
+    os> source=people | eval latest = latest("+1s", now()) | fields latest | head 1
+    fetched rows / total rows = 1/1
+    +--------+
+    | latest |
+    |--------|
+    | True   |
+    +--------+
+
+
 ### `LOCALTIMESTAMP`
 
 **Description:**
@@ -738,7 +814,7 @@ Example:
 **Description:**
 
 
-**Usage:** relative_timestamp(str) returns a relative timestamp corresponding to the given relative string and the
+**Usage:** relative_timestamp(string) returns a relative timestamp corresponding to the given relative string and the
 current timestamp at the time of query execution.
 
 The relative timestamp string has syntax `[+|-]<offset_time_integer><offset_time_unit>@<snap_time_unit>`, and is
@@ -750,9 +826,12 @@ made up of two optional components.
   specified), and rounds the time <i>down</i> to the start of the specified time unit. For example, `@wk` is the start
   of the current week (Sunday is considered to be the first day of the week).
 
-The special relative timestamp string `now`, corresponding to the current timestamp, is also supported. The current
-timestamp is determined once at the start of query execution, and is used for all relative timestamp calculations for
-that query.
+The special relative timestamp string `now`, corresponding to the current timestamp, is also supported.
+
+The current timestamp is determined once at the start of query execution, and is used for all relative timestamp
+calculations for that query. The Spark session time zone (`spark.sql.session.timeZone`) is used for determining
+relative timestamps, and accounts for changes in the time zone offset (e.g. daylight savings time); as a result, adding
+one day (`+1d`) is not the same as adding twenty-four hours (`+24h`).
 
 The relative timestamp string is case-insensitive.
 

docs/ppl-lang/ppl-where-command.md

@@ -62,3 +62,4 @@ PPL query:
       | where case(factor = 2, 'even', factor = 4, 'even', factor = 6, 'even', factor = 8, 'even' else 'odd') = 'even'
       |  stats count() by factor`
 - `source = table | where timestamp >= relative_timestamp("-1d@w6")`
+- `source = table | where earliest("-1d@w0", timestamp) and latest("now")`

integ-test/src/integration/scala/org/opensearch/flint/spark/ppl/FlintSparkPPLBuiltInDateTimeFunctionITSuite.scala

@@ -406,10 +406,34 @@ class FlintSparkPPLBuiltInDateTimeFunctionITSuite
     assertSameRows(Seq(Row(true)), frame)
   }
 
+  test("test EARLIEST") {
+    var frame = sql(s"""
+                       | source=$testTable
+                       | | eval earliest_second_before = earliest("-1s", now())
+                       | | eval earliest_now = earliest("now", now())
+                       | | eval earliest_second_after = earliest("+1s", now())
+                       | | fields earliest_second_before, earliest_now, earliest_second_after
+                       | | head 1
+                       | """.stripMargin)
+    assertSameRows(Seq(Row(true, true, false)), frame)
+  }
+
+  test("test LATEST") {
+    var frame = sql(s"""
+                       | source=$testTable
+                       | | eval latest_second_before = latest("-1s", now())
+                       | | eval latest_now = latest("now", now())
+                       | | eval latest_second_after = latest("+1s", now())
+                       | | fields latest_second_before, latest_now, latest_second_after
+                       | | head 1
+                       | """.stripMargin)
+    assertSameRows(Seq(Row(false, true, true)), frame)
+  }
+
   // TODO #957: Support earliest
   ignore("test EARLIEST") {
     var frame = sql(s"""
-                       | source=$testTable
+                       | source = $testTable
                        | | eval earliest_hour_before = earliest(now(), "-1h")
                        | | eval earliest_now = earliest(now(), "now")
                        | | eval earliest_hour_after = earliest(now(), "+1h")
@@ -422,7 +446,7 @@ class FlintSparkPPLBuiltInDateTimeFunctionITSuite
   // TODO #957: Support latest
   ignore("test LATEST") {
     var frame = sql(s"""
-                       | source=$testTable
+                       | source = $testTable
                        | | eval latest_hour_before = latest(now(), "-1h")
                        | | eval latest_now = latest(now(), "now")
                        | | eval latest_hour_after = latest(now(), "+1h")

ppl-spark-integration/src/main/antlr4/OpenSearchPPLLexer.g4

@@ -247,10 +247,6 @@ FIRST:                              'FIRST';
 LAST:                               'LAST';
 LIST:                               'LIST';
 VALUES:                             'VALUES';
-EARLIEST:                           'EARLIEST';
-EARLIEST_TIME:                      'EARLIEST_TIME';
-LATEST:                             'LATEST';
-LATEST_TIME:                        'LATEST_TIME';
 PER_DAY:                            'PER_DAY';
 PER_HOUR:                           'PER_HOUR';
 PER_MINUTE:                         'PER_MINUTE';
@@ -338,7 +334,6 @@ MONTHNAME:                          'MONTHNAME';
 NOW:                                'NOW';
 PERIOD_ADD:                         'PERIOD_ADD';
 PERIOD_DIFF:                        'PERIOD_DIFF';
-RELATIVE_TIMESTAMP:                 'RELATIVE_TIMESTAMP';
 SEC_TO_TIME:                        'SEC_TO_TIME';
 STR_TO_DATE:                        'STR_TO_DATE';
 SUBDATE:                            'SUBDATE';
@@ -360,6 +355,11 @@ UTC_TIMESTAMP:                      'UTC_TIMESTAMP';
 WEEKDAY:                            'WEEKDAY';
 YEARWEEK:                           'YEARWEEK';
 
+// RELATIVE TIME FUNCTIONS
+RELATIVE_TIMESTAMP:                 'RELATIVE_TIMESTAMP';
+EARLIEST:                           'EARLIEST';
+LATEST:                             'LATEST';
+
 // TEXT FUNCTIONS
 SUBSTR:                             'SUBSTR';
 SUBSTRING:                          'SUBSTRING';

ppl-spark-integration/src/main/antlr4/OpenSearchPPLParser.g4

@@ -755,7 +755,6 @@ dateTimeFunctionName
    | NOW
    | PERIOD_ADD
    | PERIOD_DIFF
-   | RELATIVE_TIMESTAMP
    | QUARTER
    | SECOND
    | SECOND_OF_MINUTE
@@ -780,6 +779,13 @@ dateTimeFunctionName
    | WEEK_OF_YEAR
    | YEAR
    | YEARWEEK
+   | relativeTimeFunctionName
+   ;
+
+relativeTimeFunctionName
+   : RELATIVE_TIMESTAMP
+   | EARLIEST
+   | LATEST
    ;
 
 getFormatFunction
@@ -1171,10 +1177,6 @@ keywordsCanBeId
    | LAST
    | LIST
    | VALUES
-   | EARLIEST
-   | EARLIEST_TIME
-   | LATEST
-   | LATEST_TIME
    | PER_DAY
    | PER_HOUR
    | PER_MINUTE

ppl-spark-integration/src/main/java/org/opensearch/sql/expression/function/BuiltinFunctionName.java

@@ -133,8 +133,10 @@ public enum BuiltinFunctionName {
   LOCALTIMESTAMP(FunctionName.of("localtimestamp")),
   SYSDATE(FunctionName.of("sysdate")),
 
-  // Relative timestamp functions
+  // Relative time functions
   RELATIVE_TIMESTAMP(FunctionName.of("relative_timestamp")),
+  EARLIEST(FunctionName.of("earliest")),
+  LATEST(FunctionName.of("latest")),
 
   /** Text Functions. */
   TOSTRING(FunctionName.of("tostring")),

ppl-spark-integration/src/main/java/org/opensearch/sql/expression/function/SerializableUdf.java

@@ -227,13 +227,7 @@ public Instant apply(String relativeString, Object currentTimestamp, String zone
                             ? ((Timestamp) currentTimestamp).toInstant()
                             : (Instant) currentTimestamp;
 
-            /// The Spark session time zone (`spark.sql.session.timeZone`)
-            /// is used, which may be different from the system time zone.
             ZoneId zoneId = ZoneId.of(zoneIdString);
-
-            /// Relative time calculations are performed using [ZonedDateTime] because offsets (e.g. one hour ago)
-            /// need to account for changes in the time zone offset (e.g. daylight savings time), while snaps (e.g.
-            /// start of previous Wednesday) need to account for the local date time.
             ZonedDateTime currentDateTime = ZonedDateTime.ofInstant(currentInstant, zoneId);
             ZonedDateTime relativeDateTime = TimeUtils.getRelativeZonedDateTime(relativeString, currentDateTime);
 

ppl-spark-integration/src/main/java/org/opensearch/sql/ppl/utils/BuiltinFunctionTransformer.java

@@ -12,6 +12,8 @@
 import org.apache.spark.sql.catalyst.expressions.CurrentTimestamp$;
 import org.apache.spark.sql.catalyst.expressions.DateAddInterval$;
 import org.apache.spark.sql.catalyst.expressions.Expression;
+import org.apache.spark.sql.catalyst.expressions.GreaterThanOrEqual$;
+import org.apache.spark.sql.catalyst.expressions.LessThanOrEqual$;
 import org.apache.spark.sql.catalyst.expressions.Literal$;
 import org.apache.spark.sql.catalyst.expressions.ScalaUDF;
 import org.apache.spark.sql.catalyst.expressions.TimestampAdd$;
@@ -37,13 +39,15 @@
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.DATE_SUB;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.DAY_OF_MONTH;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.COALESCE;
+import static org.opensearch.sql.expression.function.BuiltinFunctionName.EARLIEST;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON_ARRAY;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON_ARRAY_LENGTH;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON_EXTRACT;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON_KEYS;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON_OBJECT;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.JSON_VALID;
+import static org.opensearch.sql.expression.function.BuiltinFunctionName.LATEST;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.SUBTRACT;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.MULTIPLY;
 import static org.opensearch.sql.expression.function.BuiltinFunctionName.DIVIDE;
@@ -174,9 +178,23 @@ public interface BuiltinFunctionTransformer {
             args -> {
                 return ToUTCTimestamp$.MODULE$.apply(CurrentTimestamp$.MODULE$.apply(), CurrentTimeZone$.MODULE$.apply());
             })
+
+        // Relative time functions
+        .put(
+                RELATIVE_TIMESTAMP,
+                BuiltinFunctionTransformer::buildRelativeTimestampExpression)
+        .put(
+                EARLIEST,
+                args ->
+                        LessThanOrEqual$.MODULE$.apply(
+                                buildRelativeTimestampExpression(List.of(args.get(0))),
+                                args.get(1)))
         .put(
-            RELATIVE_TIMESTAMP,
-            args -> SerializableUdf.visit("relative_timestamp", List.of(args.get(0), CurrentTimestamp$.MODULE$.apply(), CurrentTimeZone$.MODULE$.apply())))
+                LATEST,
+                args ->
+                        GreaterThanOrEqual$.MODULE$.apply(
+                                buildRelativeTimestampExpression(List.of(args.get(0))),
+                                args.get(1)))
         .build();
 
     static Expression builtinFunction(org.opensearch.sql.ast.expression.Function function, List<Expression> args) {
@@ -218,4 +236,10 @@ static Expression[] createIntervalArgs(IntervalUnit unit, Expression value) {
         }
         return args;
     }
+
+    private static Expression buildRelativeTimestampExpression(List<Expression> args) {
+        return SerializableUdf.visit(
+                RELATIVE_TIMESTAMP.getName().getFunctionName(),
+                List.of(args.get(0), CurrentTimestamp$.MODULE$.apply(), CurrentTimeZone$.MODULE$.apply()));
+    }
 }