[SPARK-45157][SQL] Avoid repeated if checks in [On|Off|HeapColumnVector

### What changes were proposed in this pull request?

This is a small followup of #42850. `getBytes` checks if the `dictionary` is null or not, then call `getByte` which also checks if the `dictionary` is null or not. This PR avoids the repeated if checks by copying one line code from `getByte` to `getBytes`. The same applies to other `getXXX` methods.

### Why are the changes needed?

Make the perf-critical path more efficient.

### Does this PR introduce _any_ user-facing change?

no

### How was this patch tested?

existing tests

### Was this patch authored or co-authored using generative AI tooling?

No

Closes #42903 from cloud-fan/vector.

Authored-by: Wenchen Fan <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: cloud-fan

sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/OffHeapColumnVector.java

@@ -218,7 +218,7 @@ public byte[] getBytes(int rowId, int count) {
       Platform.copyMemory(null, data + rowId, array, Platform.BYTE_ARRAY_OFFSET, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getByte(rowId + i);
+        array[i] = (byte) dictionary.decodeToInt(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -279,7 +279,7 @@ public short[] getShorts(int rowId, int count) {
       Platform.copyMemory(null, data + rowId * 2L, array, Platform.SHORT_ARRAY_OFFSET, count * 2L);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getShort(rowId + i);
+        array[i] = (short) dictionary.decodeToInt(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -345,7 +345,7 @@ public int[] getInts(int rowId, int count) {
       Platform.copyMemory(null, data + rowId * 4L, array, Platform.INT_ARRAY_OFFSET, count * 4L);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getInt(rowId + i);
+        array[i] = dictionary.decodeToInt(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -423,7 +423,7 @@ public long[] getLongs(int rowId, int count) {
       Platform.copyMemory(null, data + rowId * 8L, array, Platform.LONG_ARRAY_OFFSET, count * 8L);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getLong(rowId + i);
+        array[i] = dictionary.decodeToLong(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -487,7 +487,7 @@ public float[] getFloats(int rowId, int count) {
       Platform.copyMemory(null, data + rowId * 4L, array, Platform.FLOAT_ARRAY_OFFSET, count * 4L);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getFloat(rowId + i);
+        array[i] = dictionary.decodeToFloat(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -553,7 +553,7 @@ public double[] getDoubles(int rowId, int count) {
         count * 8L);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getDouble(rowId + i);
+        array[i] = dictionary.decodeToDouble(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;

sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/OnHeapColumnVector.java

@@ -216,7 +216,7 @@ public byte[] getBytes(int rowId, int count) {
       System.arraycopy(byteData, rowId, array, 0, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getByte(rowId + i);
+        array[i] = (byte) dictionary.decodeToInt(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -276,7 +276,7 @@ public short[] getShorts(int rowId, int count) {
       System.arraycopy(shortData, rowId, array, 0, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getShort(rowId + i);
+        array[i] = (short) dictionary.decodeToInt(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -337,7 +337,7 @@ public int[] getInts(int rowId, int count) {
       System.arraycopy(intData, rowId, array, 0, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getInt(rowId + i);
+        array[i] = dictionary.decodeToInt(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -409,7 +409,7 @@ public long[] getLongs(int rowId, int count) {
       System.arraycopy(longData, rowId, array, 0, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getLong(rowId + i);
+        array[i] = dictionary.decodeToLong(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -466,7 +466,7 @@ public float[] getFloats(int rowId, int count) {
       System.arraycopy(floatData, rowId, array, 0, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getFloat(rowId + i);
+        array[i] = dictionary.decodeToFloat(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;
@@ -525,7 +525,7 @@ public double[] getDoubles(int rowId, int count) {
       System.arraycopy(doubleData, rowId, array, 0, count);
     } else {
       for (int i = 0; i < count; i++) {
-        array[i] = getDouble(rowId + i);
+        array[i] = dictionary.decodeToDouble(dictionaryIds.getDictId(rowId + i));
       }
     }
     return array;