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https://issues.apache.org/jira/browse/PHOENIX-1580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14395476#comment-14395476
]
Maryann Xue commented on PHOENIX-1580:
--------------------------------------
This is what I put in ParseNodeFactory.select(), very simple straight-forward
steps:
{code}
+ public SelectStatement select(List<SelectStatement> statements,
List<OrderByNode> orderBy, LimitNode limit, int bindCount) {
+ if (statements.size() == 1)
+ return statements.get(0);
+
+ return select(null, HintNode.EMPTY_HINT_NODE, false,
Lists.newArrayList(aliasedNode(null, wildcard())),
+ null, null, null, null, limit, bindCount, false, false,
statements);
+ }
+
{code}
And this is what compiler does for ORDER-BY and LIMIT push down:
{code}
+ public QueryPlan compileUnionAll(SelectStatement select) throws
SQLException {
+ List<SelectStatement> unionAllSelects = select.getSelects();
+ List<QueryPlan> plans = new ArrayList<QueryPlan>();
+
+ int numSelects = unionAllSelects.size();
+ for (int i=0; i < numSelects; i++ ) {
+ SelectStatement subSelect = unionAllSelects.get(i);
+ // Push down order-by and limit into sub-selects.
+ if (!select.getOrderBy().isEmpty() || select.getLimit() != null) {
+ subSelect = NODE_FACTORY.select(subSelect,
select.getOrderBy(), select.getLimit());
+ }
+ QueryPlan subPlan = compileSubquery(subSelect);
+ TupleProjector projector = new
TupleProjector(subPlan.getProjector());
+ subPlan = new TupleProjectionPlan(subPlan, projector, null);
+ plans.add(subPlan);
+ }
+ UnionCompiler.checkProjectionNumAndTypes(plans);
+
+ TableRef tableRef = UnionCompiler.contructSchemaTable(statement,
plans.get(0));
+ ColumnResolver resolver = FromCompiler.getResolver(tableRef);
+ StatementContext context = new StatementContext(statement, resolver,
scan, sequenceManager);
+
+ QueryPlan plan = compileSingleFlatQuery(context, select,
statement.getParameters(), false, false, null, null, false);
+ plan = new UnionPlan(context, select, tableRef, plan.getProjector(),
plan.getLimit(), plan.getOrderBy(), GroupBy.EMPTY_GROUP_BY, plans, null);
+ return plan;
+ }
{code}
> Support UNION ALL
> -----------------
>
> Key: PHOENIX-1580
> URL: https://issues.apache.org/jira/browse/PHOENIX-1580
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Alicia Ying Shu
> Assignee: Alicia Ying Shu
> Attachments: PHOENIX-1580-grammar.patch, Phoenix-1580-v1.patch,
> Phoenix-1580-v2.patch, Phoenix-1580-v3.patch, Phoenix-1580-v4.patch,
> Phoenix-1580-v5.patch, Phoenix-1580-v6.patch, Phoenix-1580-v7.patch,
> Phoenix-1580-v8.patch, phoenix-1580-v1-wipe.patch, phoenix-1580.patch,
> unionall-wipe.patch
>
>
> Select * from T1
> UNION ALL
> Select * from T2
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