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Indexes with INCLUDE columns and their support in B-tree

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This patch introduces INCLUDE clause to index definition.  This clause
specifies a list of columns which will be included as a non-key part in
the index.  The INCLUDE columns exist solely to allow more queries to
benefit from index-only scans.  Also, such columns don't need to have
appropriate operator classes.  Expressions are not supported as INCLUDE
columns since they cannot be used in index-only scans.

Index access methods supporting INCLUDE are indicated by amcaninclude flag
in IndexAmRoutine.  For now, only B-tree indexes support INCLUDE clause.

In B-tree indexes INCLUDE columns are truncated from pivot index tuples
(tuples located in non-leaf pages and high keys).  Therefore, B-tree indexes
now might have variable number of attributes.  This patch also provides
generic facility to support that: pivot tuples contain number of their
attributes in t_tid.ip_posid.  Free 13th bit of t_info is used for indicating
that.  This facility will simplify further support of index suffix truncation.
The changes of above are backward-compatible, pg_upgrade doesn't need special
handling of B-tree indexes for that.

Bump catalog version

Author: Anastasia Lubennikova with contribition by Alexander Korotkov and me
Reviewed by: Peter Geoghegan, Tomas Vondra, Antonin Houska, Jeff Janes,
			 David Rowley, Alexander Korotkov
Discussion: https://www.postgresql.org/message-id/flat/56168952.4010101@postgrespro.ru
This commit is contained in:
Teodor Sigaev
2018-04-07 23:00:39 +03:00
parent 01bb85169a
commit 8224de4f42
89 changed files with 2112 additions and 467 deletions
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2
src/backend/optimizer/path/indxpath.c
View File

@ -2162,7 +2162,7 @@ match_eclass_clauses_to_index(PlannerInfo *root, IndexOptInfo *index,
if (!index->rel->has_eclass_joins)
return;
for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
{
ec_member_matches_arg arg;
List *clauses;

13
src/backend/optimizer/path/pathkeys.c
View File

@ -447,8 +447,10 @@ get_cheapest_parallel_safe_total_inner(List *paths)
* If 'scandir' is BackwardScanDirection, build pathkeys representing a
* backwards scan of the index.
*
* The result is canonical, meaning that redundant pathkeys are removed;
* it may therefore have fewer entries than there are index columns.
* We iterate only key columns of covering indexes, since non-key columns
* don't influence index ordering. The result is canonical, meaning that
* redundant pathkeys are removed; it may therefore have fewer entries than
* there are key columns in the index.
*
* Another reason for stopping early is that we may be able to tell that
* an index column's sort order is uninteresting for this query. However,
@ -477,6 +479,13 @@ build_index_pathkeys(PlannerInfo *root,
bool nulls_first;
PathKey *cpathkey;
/*
* INCLUDE columns are stored in index unordered, so they don't
* support ordered index scan.
*/
if (i >= index->nkeycolumns)
break;
/* We assume we don't need to make a copy of the tlist item */
indexkey = indextle->expr;