(spark) branch master updated: [SPARK-46070][SQL] Compile regex pattern in SparkDateTimeUtils.getZoneId outside the hot loop

[maxgekk]

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The following commit(s) were added to refs/heads/master by this push:
     new 240706600db [SPARK-46070][SQL] Compile regex pattern in 
SparkDateTimeUtils.getZoneId outside the hot loop
240706600db is described below

commit 240706600dbf257dfcf378acaadd608348d666aa
Author: Tanel Kiis <tanel.k...@gmail.com>
AuthorDate: Thu Nov 23 18:30:37 2023 +0300

    [SPARK-46070][SQL] Compile regex pattern in SparkDateTimeUtils.getZoneId 
outside the hot loop
    
    ### What changes were proposed in this pull request?
    
    Compile the regex patterns used in `SparkDateTimeUtils.getZoneId` outside 
of the method, that can be called for each dataset row..
    
    ### Why are the changes needed?
    
    `String.replaceFirst` internally does 
`Pattern.compile(regex).matcher(this).replaceFirst(replacement)`. 
`Pattern.compile` is very expensive method, that should not be called in a loop.
    
    When using method like `from_utc_timestamp` with non-literal timezone, the 
`SparkDateTimeUtils.getZoneId` is called for each loop. In one of my usecases 
adding `from_utc_timestamp` increased the runtime from 15min to 6h.
    
    ### Does this PR introduce _any_ user-facing change?
    
    Performance improvement.
    
    ### How was this patch tested?
    
    Existing UTs
    
    ### Was this patch authored or co-authored using generative AI tooling?
    
    No
    
    Closes #43976 from tanelk/SPARK-46070_precompile_regex.
    
    Authored-by: Tanel Kiis <tanel.k...@gmail.com>
    Signed-off-by: Max Gekk <max.g...@gmail.com>
---
 .../apache/spark/sql/catalyst/util/SparkDateTimeUtils.scala | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git 
a/sql/api/src/main/scala/org/apache/spark/sql/catalyst/util/SparkDateTimeUtils.scala
 
b/sql/api/src/main/scala/org/apache/spark/sql/catalyst/util/SparkDateTimeUtils.scala
index f8a9274a564..5e9fb0dd25f 100644
--- 
a/sql/api/src/main/scala/org/apache/spark/sql/catalyst/util/SparkDateTimeUtils.scala
+++ 
b/sql/api/src/main/scala/org/apache/spark/sql/catalyst/util/SparkDateTimeUtils.scala
@@ -20,6 +20,7 @@ import java.sql.{Date, Timestamp}
 import java.time.{Instant, LocalDate, LocalDateTime, LocalTime, ZonedDateTime, 
ZoneId, ZoneOffset}
 import java.util.TimeZone
 import java.util.concurrent.TimeUnit.{MICROSECONDS, NANOSECONDS}
+import java.util.regex.Pattern
 
 import scala.util.control.NonFatal
 
@@ -36,12 +37,14 @@ trait SparkDateTimeUtils {
 
   final val TimeZoneUTC = TimeZone.getTimeZone("UTC")
 
+  final val singleHourTz = Pattern.compile("(\\+|\\-)(\\d):")
+  final val singleMinuteTz = Pattern.compile("(\\+|\\-)(\\d\\d):(\\d)$")
+
   def getZoneId(timeZoneId: String): ZoneId = {
-    val formattedZoneId = timeZoneId
-      // To support the (+|-)h:mm format because it was supported before Spark 
3.0.
-      .replaceFirst("(\\+|\\-)(\\d):", "$10$2:")
-      // To support the (+|-)hh:m format because it was supported before Spark 
3.0.
-      .replaceFirst("(\\+|\\-)(\\d\\d):(\\d)$", "$1$2:0$3")
+    // To support the (+|-)h:mm format because it was supported before Spark 
3.0.
+    var formattedZoneId = 
singleHourTz.matcher(timeZoneId).replaceFirst("$10$2:")
+    // To support the (+|-)hh:m format because it was supported before Spark 
3.0.
+    formattedZoneId = 
singleMinuteTz.matcher(formattedZoneId).replaceFirst("$1$2:0$3")
 
     ZoneId.of(formattedZoneId, ZoneId.SHORT_IDS)
   }


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