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From x..@apache.org
Subject hive git commit: HIVE-16311: Improve the performance for FastHiveDecimalImpl.fastDivide (Colin Ma, reviewed by Xuefu Zhang)
Date Fri, 21 Apr 2017 05:22:57 GMT
Repository: hive
Updated Branches:
  refs/heads/master 182218b76 -> 739c6ce53


HIVE-16311: Improve the performance for FastHiveDecimalImpl.fastDivide (Colin Ma, reviewed
by Xuefu Zhang)


Project: http://git-wip-us.apache.org/repos/asf/hive/repo
Commit: http://git-wip-us.apache.org/repos/asf/hive/commit/739c6ce5
Tree: http://git-wip-us.apache.org/repos/asf/hive/tree/739c6ce5
Diff: http://git-wip-us.apache.org/repos/asf/hive/diff/739c6ce5

Branch: refs/heads/master
Commit: 739c6ce53c228395f07238288db09445b3abf805
Parents: 182218b
Author: Ferdinand Xu <cheng.a.xu@intel.com>
Authored: Fri Apr 21 09:59:30 2017 +0800
Committer: Ferdinand Xu <cheng.a.xu@intel.com>
Committed: Fri Apr 21 09:59:30 2017 +0800

----------------------------------------------------------------------
 .../hive/common/type/FastHiveDecimalImpl.java   | 70 ++++++++++++--------
 1 file changed, 44 insertions(+), 26 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hive/blob/739c6ce5/storage-api/src/java/org/apache/hadoop/hive/common/type/FastHiveDecimalImpl.java
----------------------------------------------------------------------
diff --git a/storage-api/src/java/org/apache/hadoop/hive/common/type/FastHiveDecimalImpl.java
b/storage-api/src/java/org/apache/hadoop/hive/common/type/FastHiveDecimalImpl.java
index f733c1e..88abf3c 100644
--- a/storage-api/src/java/org/apache/hadoop/hive/common/type/FastHiveDecimalImpl.java
+++ b/storage-api/src/java/org/apache/hadoop/hive/common/type/FastHiveDecimalImpl.java
@@ -841,37 +841,34 @@ public class FastHiveDecimalImpl extends FastHiveDecimal {
         // For some strange reason BigDecimal 0 can have a scale.  We do not support that.
         bigDecimal = BigDecimal.ZERO;
       }
-    } else {
-      BigDecimal bigDecimalStripped = bigDecimal.stripTrailingZeros();
-      int stripTrailingZerosScale = bigDecimalStripped.scale();
-      // System.out.println("FAST_SET_FROM_BIG_DECIMAL bigDecimal " + bigDecimal);
-      // System.out.println("FAST_SET_FROM_BIG_DECIMAL bigDecimalStripped " + bigDecimalStripped);
-      // System.out.println("FAST_SET_FROM_BIG_DECIMAL stripTrailingZerosScale " + stripTrailingZerosScale);
-      if (stripTrailingZerosScale < 0) {
-
-        // The trailing zeroes extend into the integer part -- we only want to eliminate
the
-        // fractional zero digits.
+    }
 
-        bigDecimal = bigDecimal.setScale(0);
-      } else {
+    if (!allowRounding) {
+      if (bigDecimal.signum() != 0) {
+        BigDecimal bigDecimalStripped = bigDecimal.stripTrailingZeros();
+        int stripTrailingZerosScale = bigDecimalStripped.scale();
+        // System.out.println("FAST_SET_FROM_BIG_DECIMAL bigDecimal " + bigDecimal);
+        // System.out.println("FAST_SET_FROM_BIG_DECIMAL bigDecimalStripped " + bigDecimalStripped);
+        // System.out.println("FAST_SET_FROM_BIG_DECIMAL stripTrailingZerosScale " + stripTrailingZerosScale);
+        if (stripTrailingZerosScale < 0) {
+
+          // The trailing zeroes extend into the integer part -- we only want to eliminate
the
+          // fractional zero digits.
+
+          bigDecimal = bigDecimal.setScale(0);
+        } else {
 
-        // Ok, use result with some or all fractional digits stripped.
+          // Ok, use result with some or all fractional digits stripped.
 
-        bigDecimal = bigDecimalStripped;
+          bigDecimal = bigDecimalStripped;
+        }
       }
-    }
-    // System.out.println("FAST_SET_FROM_BIG_DECIMAL adjusted for zeroes/scale " + bigDecimal
+ " scale " + bigDecimal.scale());
-
-    BigInteger unscaledValue = bigDecimal.unscaledValue();
-    // System.out.println("FAST_SET_FROM_BIG_DECIMAL unscaledValue " + unscaledValue + "
length " + unscaledValue.toString().length());
-
-    final int scale = bigDecimal.scale();
-    if (!allowRounding) {
+      int scale = bigDecimal.scale();
       if (scale < 0 || scale > HiveDecimal.MAX_SCALE) {
         return false;
       }
       // The digits must fit without rounding.
-      if (!fastSetFromBigInteger(unscaledValue, fastResult)) {
+      if (!fastSetFromBigInteger(bigDecimal.unscaledValue(), fastResult)) {
         return false;
       }
       if (fastResult.fastSignum != 0) {
@@ -881,7 +878,8 @@ public class FastHiveDecimalImpl extends FastHiveDecimal {
       return true;
     }
     // This method will scale down and round to fit, if necessary.
-    if (!fastSetFromBigInteger(unscaledValue, scale, fastResult)) {
+    if (!fastSetFromBigInteger(bigDecimal.unscaledValue(), bigDecimal.scale(),
+        bigDecimal.precision(), fastResult)) {
       return false;
     }
     return true;
@@ -1128,6 +1126,24 @@ public class FastHiveDecimalImpl extends FastHiveDecimal {
    */
   public static boolean fastSetFromBigInteger(
       BigInteger bigInteger, int scale, FastHiveDecimal fastResult) {
+    // Poor performance, because the precision will be calculated by bigInteger.toString()
+    return fastSetFromBigInteger(bigInteger, scale, -1, fastResult);
+  }
+
+  /**
+   * Creates a fast decimal from a BigInteger with a specified scale.
+   *
+   * NOTE: The fastSetFromBigInteger method requires the caller to pass a fastResult
+   * parameter has been reset for better performance.
+   *
+   * @param bigInteger the value to set as an integer
+   * @param scale the scale to use
+   * @param precision the precision to use
+   * @param fastResult an object to reuse
+   * @return True if the BigInteger and scale were successfully converted to a decimal.
+   */
+  public static boolean fastSetFromBigInteger(
+      BigInteger bigInteger, int scale, int precision, FastHiveDecimal fastResult) {
 
     if (scale < 0) {
 
@@ -1150,8 +1166,10 @@ public class FastHiveDecimalImpl extends FastHiveDecimal {
       bigInteger = bigInteger.negate();
     }
 
-    // A slow way to get the number of decimal digits.
-    int precision = bigInteger.toString().length();
+    if (precision < 0) {
+      // A slow way to get the number of decimal digits.
+      precision = bigInteger.toString().length();
+    }
 
     // System.out.println("FAST_SET_FROM_BIG_INTEGER adjusted bigInteger " + bigInteger +
" precision " + precision);
 


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