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CREATE INDEX ... INCLUDING (column[, ...])

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Now indexes (but only B-tree for now) can contain "extra" column(s) which
doesn't participate in index structure, they are just stored in leaf
tuples. It allows to use index only scan by using single index instead
of two or more indexes.

Author: Anastasia Lubennikova with minor editorializing by me
Reviewers: David Rowley, Peter Geoghegan, Jeff Janes
This commit is contained in:
Teodor Sigaev
2016-04-08 19:31:49 +03:00
parent 339025c68f
commit 386e3d7609
68 changed files with 1321 additions and 256 deletions
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31
src/backend/access/common/indextuple.c
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@@ -19,6 +19,7 @@
#include "access/heapam.h"
#include "access/itup.h"
#include "access/tuptoaster.h"
#include "utils/rel.h"
/* ----------------------------------------------------------------
@@ -441,3 +442,33 @@ CopyIndexTuple(IndexTuple source)
memcpy(result, source, size);
return result;
}
/*
* Reform index tuple. Truncate nonkey (INCLUDING) attributes.
*/
IndexTuple
index_truncate_tuple(Relation idxrel, IndexTuple olditup)
{
TupleDesc itupdesc = RelationGetDescr(idxrel);
Datum values[INDEX_MAX_KEYS];
bool isnull[INDEX_MAX_KEYS];
IndexTuple newitup;
int indnatts = IndexRelationGetNumberOfAttributes(idxrel);
int indnkeyatts = IndexRelationGetNumberOfKeyAttributes(idxrel);
Assert(indnatts <= INDEX_MAX_KEYS);
Assert(indnkeyatts > 0);
Assert(indnkeyatts < indnatts);
index_deform_tuple(olditup, itupdesc, values, isnull);
/* form new tuple that will contain only key attributes */
itupdesc->natts = indnkeyatts;
newitup = index_form_tuple(itupdesc, values, isnull);
newitup->t_tid = olditup->t_tid;
itupdesc->natts = indnatts;
Assert(IndexTupleSize(newitup) <= IndexTupleSize(olditup));
return newitup;
}