twdsilva commented on a change in pull request #515: PHOENIX-5318 Slots passed
to SkipScan filter is incorrect for desc pr…
URL: https://github.com/apache/phoenix/pull/515#discussion_r291697101
##########
File path: phoenix-core/src/main/java/org/apache/phoenix/query/KeyRange.java
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@@ -108,6 +109,34 @@ public KeyRange apply(byte[] input) {
}
};
Review comment:
@dbwong ```KeyRange.COMPARATOR.reversed()``` will not give the correct
behavior.
For eg for the query Where COL1='1' OR COL1='12' OR COL1='2'
the key range before sorting is
```
0 = {KeyRange@8864} "\xCE" -> "1"
1 = {KeyRange@8865} "\xCE\xCD" -> "12"
2 = {KeyRange@8866} "\xCD" -> "2"
```
Sorting using ```KeyRange.COMPARATOR``` gives the following which isn't
correct.
```
0 = {KeyRange@8879} "\xCD" -> "2"
1 = {KeyRange@8880} "\xCE" -> "1"
2 = {KeyRange@8881} "\xCE\xCD" -> "12"
```
Using ```KeyRange.COMPARATOR.reverse()``` just reverses the following order
which isn't correct.
We need "12" to sort before "1" as thats how its stored on disk. Using
```DescVarLengthFastByteComparisons``` gives the correct ordering:
```
0 = {KeyRange@8899} "\xCD" -> "2"
1 = {KeyRange@8900} "\xCE\xCD" -> "12
2 = {KeyRange@8901} "\xCE" -> "1"
```
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