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https://issues.apache.org/jira/browse/PHOENIX-1516?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14255215#comment-14255215
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James Taylor commented on PHOENIX-1516:
---------------------------------------
Thanks, [~lhofhansl]. Looks good. A couple of minor items:
- For the RandomFunction, but the initialization of random in a separate init()
method which is called after readFields() which is the entry point of
construction for server-side usage (i.e. if RAND() is used in a WHERE clause):
{code}
+@BuiltInFunction(name = RandomFunction.NAME, args =
{@Argument(allowedTypes={PLong.class},defaultValue="null",isConstant=true)})
+public class RandomFunction extends ScalarFunction {
+ public static final String NAME = "RAND";
+ private final Random random;
+ private final boolean hasSeed;
+ private Double current;
+
+ public RandomFunction(List<Expression> children) {
+ super(children);
+ init();
+ }
+
+ @Override
+ public void readFields(DataInput input) throws IOException {
+ super.readFields(input);
+ init();
+ }
+
+ private void init() {
+ Number seed = (Number)((LiteralExpression)children.get(0)).getValue();
+ random = seed == null ? new Random() : new Random(seed.longValue());
+ hasSeed = seed != null;
+ current = random.nextDouble();
+ }
{code}
- For the call to reset in PhoenixResultSet, call it after the next() call if
currentRow != null for consistency with when it's called on the server-side:
{code}
@Override
public boolean next() throws SQLException {
checkOpen();
+ if (currentRow != BEFORE_FIRST) {
+ rowProjector.reset();
+ }
try {
currentRow = scanner.next();
} catch (RuntimeException e) {
{code}
- Would be good to have a test that uses RAND in the WHERE clause, but I don't
know how you'd validate it. Maybe through a subquery as Julian suggested before?
> Add RANDOM built-in function
> ----------------------------
>
> Key: PHOENIX-1516
> URL: https://issues.apache.org/jira/browse/PHOENIX-1516
> Project: Phoenix
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Attachments: 1516-v2.txt, 1516.txt
>
>
> I often find it useful to generate some rows with random data.
> Here's a simple RANDOM() function that we could use for that.
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