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https://issues.apache.org/jira/browse/PHOENIX-476?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15598651#comment-15598651
]
Kevin Liew commented on PHOENIX-476:
------------------------------------
I got it working. With the recent changes, we access the context again during
the UPSERT so we can compile arbitrary isConstant expressions. I just needed to
revert the older changes where we were compiling the expression to a literal in
CreateTableCompiler and storing the expression string obtained from that.
For scalar date-time, the expression was untouched. For arrays, it was being
modified below:
{code:java}
public Expression visitLeave(ArrayConstructorNode node, List<Expression>
children) throws SQLException {
...
ArrayConstructorExpression arrayExpression = new
ArrayConstructorExpression(children, arrayElemDataType, rowKeyOrderOptimizable);
if (ExpressionUtil.isConstant(arrayExpression)) {
for (int i = 0; i < children.size(); i++) {
Expression child = children.get(i);
child.evaluate(null, ptr);
Object value = null;
if (child.getDataType() == null) {
value = arrayElemDataType.toObject(ptr,
theArrayElemDataType, child.getSortOrder());
} else {
value = arrayElemDataType.toObject(ptr,
child.getDataType(), child.getSortOrder());
}
elements[i] = LiteralExpression.newConstant(value,
theArrayElemDataType, child.getDeterminism()).getValue();
}
Object value =
PArrayDataType.instantiatePhoenixArray(arrayElemDataType, elements);
return LiteralExpression.newConstant(value,
PDataType.fromTypeId(arrayElemDataType.getSqlType() +
PDataType.ARRAY_TYPE_BASE), null, null, arrayExpression.getSortOrder(),
Determinism.ALWAYS, rowKeyOrderOptimizable);
}
{code}
Its just testing and cleanup left now.
> Support declaration of DEFAULT in CREATE statement
> --------------------------------------------------
>
> Key: PHOENIX-476
> URL: https://issues.apache.org/jira/browse/PHOENIX-476
> Project: Phoenix
> Issue Type: Task
> Affects Versions: 3.0-Release
> Reporter: James Taylor
> Assignee: Kevin Liew
> Labels: enhancement
> Fix For: 4.9.0
>
> Attachments: PHOENIX-476.2.patch, PHOENIX-476.3.patch,
> PHOENIX-476.4.patch, PHOENIX-476.5.patch, PHOENIX-476.6.patch,
> PHOENIX-476.7.patch, PHOENIX-476.8.patch, PHOENIX-476.patch
>
>
> Support the declaration of a default value in the CREATE TABLE/VIEW statement
> like this:
> CREATE TABLE Persons (
> Pid int NOT NULL PRIMARY KEY,
> LastName varchar(255) NOT NULL,
> FirstName varchar(255),
> Address varchar(255),
> City varchar(255) DEFAULT 'Sandnes'
> )
> To implement this, we'd need to:
> 1. add a new DEFAULT_VALUE key value column in SYSTEM.TABLE and pass through
> the value when the table is created (in MetaDataClient).
> 2. always set NULLABLE to ResultSetMetaData.columnNoNulls if a default value
> is present, since the column will never be null.
> 3. add a getDefaultValue() accessor in PColumn
> 4. for a row key column, during UPSERT use the default value if no value was
> specified for that column. This could be done in the PTableImpl.newKey method.
> 5. for a key value column with a default value, we can get away without
> incurring any storage cost. Although a little bit of extra effort than if we
> persisted the default value on an UPSERT for key value columns, this approach
> has the benefit of not incurring any storage cost for a default value.
> * serialize any default value into KeyValueColumnExpression
> * in the evaluate method of KeyValueColumnExpression, conditionally use
> the default value if the column value is not present. If doing partial
> evaluation, you should not yet return the default value, as we may not have
> encountered the the KeyValue for the column yet (since a filter evaluates
> each time it sees each KeyValue, and there may be more than one KeyValue
> referenced in the expression). Partial evaluation is determined by calling
> Tuple.isImmutable(), where false means it is NOT doing partial evaluation,
> while true means it is.
> * modify EvaluateOnCompletionVisitor by adding a visitor method for
> RowKeyColumnExpression and KeyValueColumnExpression to set
> evaluateOnCompletion to true if they have a default value specified. This
> will cause filter evaluation to execute one final time after all KeyValues
> for a row have been seen, since it's at this time we know we should use the
> default value.
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