[ https://issues.apache.org/jira/browse/PHOENIX-4690?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
chenglei updated PHOENIX-4690: ------------------------------ Attachment: (was: PHOENIX-4690.patch) > GroupBy expressions should follow the order of PK Columns if GroupBy is > orderPreserving > --------------------------------------------------------------------------------------- > > Key: PHOENIX-4690 > URL: https://issues.apache.org/jira/browse/PHOENIX-4690 > Project: Phoenix > Issue Type: Bug > Affects Versions: 4.13.2 > Reporter: chenglei > Priority: Critical > > Given a table : > {code} > create table test ( > pk1 integer not null , > pk2 integer not null, > v integer, > CONSTRAINT TEST_PK PRIMARY KEY (pk1,pk2)) > {code} > and some data: > {code} > +------+------+-----+ > | PK1 | PK2 | V | > +------+------+-----+ > | 1 | 8 | 10 | > | 1 | 9 | 11 | > | 2 | 3 | 13 | > | 2 | 7 | 15 | > | 3 | 2 | 17 | > +------+------+-----+ > {code} > for following sql : > {code} > select pk2,pk1,count(v) from test group by pk2,pk1 order by pk2,pk1 > {code} > the expected result is : > {code} > +------+------+-----------+ > | PK2 | PK1 | COUNT(V) | > +------+------+-----------+ > | 2 | 3 | 1 | > | 3 | 2 | 1 | > | 7 | 2 | 1 | > | 8 | 1 | 1 | > | 9 | 1 | 1 | > +------+------+-----------+ > {code} > but the actual result is : > {code} > +------+------+-----------+ > | PK2 | PK1 | COUNT(V) | > +------+------+-----------+ > | 8 | 1 | 1 | > | 9 | 1 | 1 | > | 3 | 2 | 1 | > | 7 | 2 | 1 | > | 2 | 3 | 1 | > +------+------+-----------+ > {code} > The problem is caused by the GroupBy.compile, obviously, in line 154, for > {{group by pk2,pk1}}, > {{OrderPreservingTracker.isOrderPreserving}} is true by reorder the > {{pk2,pk1}} following the order of PK columns {{pk1,pk2}}, but in line 158, > for the new GroupBy, the GroupBy.expressions is still {{pk2,pk1}},not the > actual {{pk1,pk2}}: > {code} > 141 public GroupBy compile(StatementContext context, TupleProjector > tupleProjector) throws SQLException { > 142 boolean isOrderPreserving = this.isOrderPreserving; > 143 int orderPreservingColumnCount = 0; > 144 if (isOrderPreserving) { > 145 OrderPreservingTracker tracker = new > OrderPreservingTracker(context, GroupBy.EMPTY_GROUP_BY, Ordering.UNORDERED, > expressions.size(), tupleProjector); > 146 for (int i = 0; i < expressions.size(); i++) { > 147 Expression expression = expressions.get(i); > 148 tracker.track(expression); > 149 } > 150 > 151 // This is true if the GROUP BY is composed of only PK > columns. We further check here that > 152 // there are no "gaps" in the PK columns positions used > (i.e. we start with the first PK > 153 // column and use each subsequent one in PK order). > 154 isOrderPreserving = tracker.isOrderPreserving(); > 155 orderPreservingColumnCount = > tracker.getOrderPreservingColumnCount(); > 156 } > 157 if (isOrderPreserving || isUngroupedAggregate) { > 158 return new > GroupBy.GroupByBuilder(this).setIsOrderPreserving(isOrderPreserving) > .setOrderPreservingColumnCount(orderPreservingColumnCount).build(); > 159 } > {code} > Then when we compile {{order by pk2,pk1}} in OrderByCompiler.compile, because > {{the GroupBy.isOrderPreserving}} is true, and {{order by pk2,pk1}} is > consistent with the GroupBy.expressions {{group by pk2,pk1}}, so the result > of {{OrderByCompiler.compile}} is {{OrderBy.FWD_ROW_KEY_ORDER_BY}}. > But in fact,because the actual GroupBy.expression is {{group by pk1,pk2}},so > we need to execute {{order by pk2,pk1}} after > the {{group by pk1,pk2}}. -- This message was sent by Atlassian JIRA (v7.6.3#76005)