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Commit75cccd0

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committed
pathkeys fixes
1 parent0ff2733 commit75cccd0

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4 files changed

+55
-24
lines changed

4 files changed

+55
-24
lines changed

‎src/backend/nodes/print.c‎

Lines changed: 15 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/nodes/print.c,v 1.22 1999/02/13 23:16:00 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/nodes/print.c,v 1.23 1999/02/20 19:02:40 momjian Exp $
1111
*
1212
* HISTORY
1313
* AUTHORDATEMAJOR EVENT
@@ -213,20 +213,28 @@ print_expr(Node *expr, List *rtable)
213213

214214
/*
215215
* print_pathkeys -
216-
*temporary here. where is keyslist oflists
216+
*pathkeys list oflist ofVar's
217217
*/
218218
void
219219
print_pathkeys(List*pathkeys,List*rtable)
220220
{
221-
List*k;
221+
List*i,*k;
222222

223223
printf("(");
224-
foreach(k,pathkeys)
224+
foreach(i,pathkeys)
225225
{
226-
Node*var=lfirst((List*)lfirst(k));
226+
Listpathkey=lfirst(i));
227227

228-
print_expr(var,rtable);
229-
if (lnext(k))
228+
printf("(");
229+
foreach(k,pathkey)
230+
{
231+
Node*var=lfirst(k);
232+
print_expr(var,rtable);
233+
if (lnext(k))
234+
printf(", ");
235+
}
236+
printf(") ");
237+
if (lnext(i))
230238
printf(", ");
231239
}
232240
printf(")\n");

‎src/backend/optimizer/path/pathkeys.c‎

Lines changed: 36 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.4 1999/02/2018:01:01 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/pathkeys.c,v 1.5 1999/02/2019:02:41 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -54,7 +54,19 @@ static List *new_matching_subkeys(Var *subkey, List *considered_subkeys,
5454
*{ {tab1.col1, tab2.col1} }. This allows future joins to use either Var
5555
*as a pre-sorted key to prevent Mergejoins from having to re-sort the Path.
5656
*They are equal, so they are both primary sort keys. This is why pathkeys
57-
*is a List of Lists. -- bjm
57+
*is a List of Lists.
58+
*
59+
*For multi-key sorts, if the outer is sorted by a multi-key index, the
60+
*multi-key index remains after the join. If the inner has a multi-key
61+
*sort, only the primary key of the inner is added to the result.
62+
*Mergejoins only join on the primary key. Currently, non-primary keys
63+
*in the pathkeys List are of limited value.
64+
*
65+
*HashJoin has similar functionality. NestJoin does not perform sorting,
66+
*and allows non-equajoins, so it does not allow useful pathkeys.
67+
*
68+
*-- bjm
69+
*
5870
*/
5971

6072
/****************************************************************************
@@ -92,17 +104,21 @@ static List *new_matching_subkeys(Var *subkey, List *considered_subkeys,
92104
*/
93105
List*
94106
order_joinkeys_by_pathkeys(List*pathkeys,
95-
List*joinkeys,
96-
List*joinclauses,
97-
intouter_or_inner,
98-
List**matchedJoinClausesPtr)
107+
List*joinkeys,
108+
List*joinclauses,
109+
intouter_or_inner,
110+
List**matchedJoinClausesPtr)
99111
{
100112
List*matched_joinkeys=NIL;
101113
List*matched_joinclauses=NIL;
102114
List*pathkey=NIL;
103115
List*i=NIL;
104116
intmatched_joinkey_index=-1;
105117

118+
/*
119+
*Reorder the joinkeys by picking out one that matches each pathkey,
120+
*and create a new joinkey/joinclause list in pathkey order
121+
*/
106122
foreach(i,pathkeys)
107123
{
108124
pathkey=lfirst(i);
@@ -118,10 +134,18 @@ order_joinkeys_by_pathkeys(List *pathkeys,
118134
matched_joinclauses=lappend(matched_joinclauses,joinclause);
119135
}
120136
else
121-
{
137+
/*A pathkey could not be matched. */
138+
break;
139+
}
140+
141+
/*
142+
*Did we fail to match all the joinkeys?
143+
*Extra pathkeys are no problem.
144+
*/
145+
if (length(joinkeys)!=length(matched_joinkeys))
146+
{
122147
*matchedJoinClausesPtr=NIL;
123148
returnNIL;
124-
}
125149
}
126150

127151
*matchedJoinClausesPtr=matched_joinclauses;
@@ -133,6 +157,8 @@ order_joinkeys_by_pathkeys(List *pathkeys,
133157
* match_pathkey_joinkeys
134158
* Returns the 0-based index into 'joinkeys' of the first joinkey whose
135159
* outer or inner subkey matches any subkey of 'pathkey'.
160+
*
161+
*All these keys are equivalent, so any of them can match. See above.
136162
*/
137163
staticint
138164
match_pathkey_joinkeys(List*pathkey,
@@ -141,8 +167,7 @@ match_pathkey_joinkeys(List *pathkey,
141167
{
142168
Var*path_subkey;
143169
intpos;
144-
List*i=NIL;
145-
List*x=NIL;
170+
List*i,*x;
146171
JoinKey*jk;
147172

148173
foreach(i,pathkey)
@@ -152,8 +177,7 @@ match_pathkey_joinkeys(List *pathkey,
152177
foreach(x,joinkeys)
153178
{
154179
jk= (JoinKey*)lfirst(x);
155-
if (var_equal(path_subkey,
156-
extract_join_key(jk,outer_or_inner)))
180+
if (var_equal(path_subkey,extract_join_key(jk,outer_or_inner)))
157181
returnpos;
158182
pos++;
159183
}

‎src/backend/optimizer/util/pathnode.c‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/pathnode.c,v 1.38 1999/02/2018:01:02 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/pathnode.c,v 1.39 1999/02/2019:02:42 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -205,7 +205,7 @@ better_path(Path *new_path, List *unique_paths, bool *is_new)
205205
{
206206
/*
207207
* Replace pathkeys that match exactly, {{1,2}}, {{1,2}}
208-
* Replace pathkeys {{1,2}}with {{1,2,3}}} if the latter is not
208+
* Replace pathkeys {{1,2}}with {{1,2,3}}} if the latter is not
209209
* more expensive and replace unordered path with ordered
210210
* path if it is not more expensive. Favor sorted keys
211211
* over unsorted keys in the same way.

‎src/include/nodes/relation.h‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
*
77
* Copyright (c) 1994, Regents of the University of California
88
*
9-
* $Id: relation.h,v 1.27 1999/02/2016:28:20 momjian Exp $
9+
* $Id: relation.h,v 1.28 1999/02/2019:02:43 momjian Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -142,8 +142,7 @@ typedef struct Path
142142

143143
PathOrder*pathorder;
144144

145-
List*pathkeys;/*
146-
* This is a List of List of Var nodes.
145+
List*pathkeys;/* This is a List of List of Var nodes.
147146
* See the top of optimizer/path/pathkeys.c
148147
* for more information.
149148
*/

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