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alvherrealvherre
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Clone extended stats in CREATE TABLE (LIKE INCLUDING ALL)
The LIKE INCLUDING ALL clause to CREATE TABLE intuitively indicates cloning of extended statistics on the source table, but it failed to do so. Patch it up so that it does. Also include an INCLUDING STATISTICS option to the LIKE clause, so that the behavior can be requested individually, or excluded individually. While at it, reorder the INCLUDING options, both in code and in docs, in alphabetical order which makes more sense than feature-implementation order that was previously used. Backpatch this to Postgres 10, where extended statistics were introduced, because this is seen as an oversight in a fresh feature which is better to get consistent from the get-go instead of changing only in pg11. In pg11, comments on statistics objects are cloned too. In pg10 they are not, because I (Álvaro) was too coward to change the parse node as required to support it. Also, in pg10 I chose not to renumber the parser symbols for the various INCLUDING options in LIKE, for the same reason. Any corresponding user-visible changes (docs) are backpatched, though. Reported-by: Stephen Froehlich Author: David Rowley Reviewed-by: Álvaro Herrera, Tomas Vondra Discussion: https://postgr.es/m/CY1PR0601MB1927315B45667A1B679D0FD5E5EF0@CY1PR0601MB1927.namprd06.prod.outlook.com
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11 files changed

+323
-37
lines changed

11 files changed

+323
-37
lines changed

‎doc/src/sgml/ref/create_table.sgml

+6-2
Original file line numberDiff line numberDiff line change
@@ -82,7 +82,7 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXI
8282

8383
<phrase>and <replaceable class="parameter">like_option</replaceable> is:</phrase>
8484

85-
{ INCLUDING | EXCLUDING } { DEFAULTS | CONSTRAINTS | IDENTITY | INDEXES | STORAGE | COMMENTS | ALL }
85+
{ INCLUDING | EXCLUDING } { COMMENTS | CONSTRAINTS | DEFAULTS | IDENTITY | INDEXES | STATISTICS | STORAGE | ALL }
8686

8787
<phrase>and <replaceable class="parameter">partition_bound_spec</replaceable> is:</phrase>
8888

@@ -591,6 +591,10 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
591591
No distinction is made between column constraints and table
592592
constraints.
593593
</para>
594+
<para>
595+
Extended statistics are copied to the new table if
596+
<literal>INCLUDING STATISTICS</literal> is specified.
597+
</para>
594598
<para>
595599
Indexes, <literal>PRIMARY KEY</literal>, <literal>UNIQUE</literal>,
596600
and <literal>EXCLUDE</literal> constraints on the original table will be
@@ -616,7 +620,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
616620
</para>
617621
<para>
618622
<literal>INCLUDING ALL</literal> is an abbreviated form of
619-
<literal>INCLUDING DEFAULTS INCLUDING IDENTITY INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING STORAGE INCLUDING COMMENTS</literal>.
623+
<literal>INCLUDING COMMENTS INCLUDING CONSTRAINTS INCLUDING DEFAULTS INCLUDING IDENTITY INCLUDING INDEXES INCLUDING STATISTICS INCLUDING STORAGE</literal>.
620624
</para>
621625
<para>
622626
Note that unlike <literal>INHERITS</literal>, columns and

‎src/backend/commands/indexcmds.c

+4-1
Original file line numberDiff line numberDiff line change
@@ -1805,7 +1805,8 @@ GetDefaultOpClass(Oid type_id, Oid am_id)
18051805
/*
18061806
* makeObjectName()
18071807
*
1808-
* Create a name for an implicitly created index, sequence, constraint, etc.
1808+
* Create a name for an implicitly created index, sequence, constraint,
1809+
* extended statistics, etc.
18091810
*
18101811
* The parameters are typically: the original table name, the original field
18111812
* name, and a "type" string (such as "seq" or "pkey"). The field name
@@ -1981,6 +1982,8 @@ ChooseIndexName(const char *tabname, Oid namespaceId,
19811982
*
19821983
* We know that less than NAMEDATALEN characters will actually be used,
19831984
* so we can truncate the result once we've generated that many.
1985+
*
1986+
* XXX See also ChooseExtendedStatisticNameAddition.
19841987
*/
19851988
static char *
19861989
ChooseIndexNameAddition(List *colnames)

‎src/backend/commands/statscmds.c

+142-27
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,7 @@
2020
#include "catalog/namespace.h"
2121
#include "catalog/pg_namespace.h"
2222
#include "catalog/pg_statistic_ext.h"
23+
#include "commands/comment.h"
2324
#include "commands/defrem.h"
2425
#include "miscadmin.h"
2526
#include "statistics/statistics.h"
@@ -31,6 +32,11 @@
3132
#include "utils/typcache.h"
3233

3334

35+
static char *ChooseExtendedStatisticName(const char *name1, const char *name2,
36+
const char *label, Oid namespaceid);
37+
static char *ChooseExtendedStatisticNameAddition(List *exprs);
38+
39+
3440
/* qsort comparator for the attnums in CreateStatistics */
3541
static int
3642
compare_int16(const void *a, const void *b)
@@ -51,7 +57,6 @@ CreateStatistics(CreateStatsStmt *stmt)
5157
int16 attnums[STATS_MAX_DIMENSIONS];
5258
int numcols = 0;
5359
char *namestr;
54-
NameData stxname;
5560
Oid statoid;
5661
Oid namespaceId;
5762
Oid stxowner = GetUserId();
@@ -75,31 +80,6 @@ CreateStatistics(CreateStatsStmt *stmt)
7580

7681
Assert(IsA(stmt, CreateStatsStmt));
7782

78-
/* resolve the pieces of the name (namespace etc.) */
79-
namespaceId = QualifiedNameGetCreationNamespace(stmt->defnames, &namestr);
80-
namestrcpy(&stxname, namestr);
81-
82-
/*
83-
* Deal with the possibility that the statistics object already exists.
84-
*/
85-
if (SearchSysCacheExists2(STATEXTNAMENSP,
86-
NameGetDatum(&stxname),
87-
ObjectIdGetDatum(namespaceId)))
88-
{
89-
if (stmt->if_not_exists)
90-
{
91-
ereport(NOTICE,
92-
(errcode(ERRCODE_DUPLICATE_OBJECT),
93-
errmsg("statistics object \"%s\" already exists, skipping",
94-
namestr)));
95-
return InvalidObjectAddress;
96-
}
97-
98-
ereport(ERROR,
99-
(errcode(ERRCODE_DUPLICATE_OBJECT),
100-
errmsg("statistics object \"%s\" already exists", namestr)));
101-
}
102-
10383
/*
10484
* Examine the FROM clause. Currently, we only allow it to be a single
10585
* simple table, but later we'll probably allow multiple tables and JOIN
@@ -148,6 +128,45 @@ CreateStatistics(CreateStatsStmt *stmt)
148128
Assert(rel);
149129
relid = RelationGetRelid(rel);
150130

131+
/*
132+
* If the node has a name, split it up and determine creation namespace.
133+
* If not (a possibility not considered by the grammar, but one which can
134+
* occur via the "CREATE TABLE ... (LIKE)" command), then we put the
135+
* object in the same namespace as the relation, and cons up a name for it.
136+
*/
137+
if (stmt->defnames)
138+
namespaceId = QualifiedNameGetCreationNamespace(stmt->defnames, &namestr);
139+
else
140+
{
141+
namespaceId = RelationGetNamespace(rel);
142+
namestr = ChooseExtendedStatisticName(RelationGetRelationName(rel),
143+
ChooseExtendedStatisticNameAddition(stmt->exprs),
144+
"stat",
145+
namespaceId);
146+
}
147+
148+
/*
149+
* Deal with the possibility that the statistics object already exists.
150+
*/
151+
if (SearchSysCacheExists2(STATEXTNAMENSP,
152+
CStringGetDatum(namestr),
153+
ObjectIdGetDatum(namespaceId)))
154+
{
155+
if (stmt->if_not_exists)
156+
{
157+
ereport(NOTICE,
158+
(errcode(ERRCODE_DUPLICATE_OBJECT),
159+
errmsg("statistics object \"%s\" already exists, skipping",
160+
namestr)));
161+
relation_close(rel, NoLock);
162+
return InvalidObjectAddress;
163+
}
164+
165+
ereport(ERROR,
166+
(errcode(ERRCODE_DUPLICATE_OBJECT),
167+
errmsg("statistics object \"%s\" already exists", namestr)));
168+
}
169+
151170
/*
152171
* Currently, we only allow simple column references in the expression
153172
* list. That will change someday, and again the grammar already supports
@@ -288,7 +307,7 @@ CreateStatistics(CreateStatsStmt *stmt)
288307
memset(values, 0, sizeof(values));
289308
memset(nulls, false, sizeof(nulls));
290309
values[Anum_pg_statistic_ext_stxrelid - 1] = ObjectIdGetDatum(relid);
291-
values[Anum_pg_statistic_ext_stxname - 1] = NameGetDatum(&stxname);
310+
values[Anum_pg_statistic_ext_stxname - 1] = CStringGetDatum(namestr);
292311
values[Anum_pg_statistic_ext_stxnamespace - 1] = ObjectIdGetDatum(namespaceId);
293312
values[Anum_pg_statistic_ext_stxowner - 1] = ObjectIdGetDatum(stxowner);
294313
values[Anum_pg_statistic_ext_stxkeys - 1] = PointerGetDatum(stxkeys);
@@ -340,6 +359,11 @@ CreateStatistics(CreateStatsStmt *stmt)
340359
* STATISTICS, which is more work than it seems worth.
341360
*/
342361

362+
/* Add any requested comment */
363+
if (stmt->stxcomment != NULL)
364+
CreateComments(statoid, StatisticExtRelationId, 0,
365+
stmt->stxcomment);
366+
343367
/* Return stats object's address */
344368
return myself;
345369
}
@@ -405,3 +429,94 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
405429
* Future types of extended stats will likely require us to work harder.
406430
*/
407431
}
432+
433+
/*
434+
* Select a nonconflicting name for a new statistics.
435+
*
436+
* name1, name2, and label are used the same way as for makeObjectName(),
437+
* except that the label can't be NULL; digits will be appended to the label
438+
* if needed to create a name that is unique within the specified namespace.
439+
*
440+
* Returns a palloc'd string.
441+
*
442+
* Note: it is theoretically possible to get a collision anyway, if someone
443+
* else chooses the same name concurrently. This is fairly unlikely to be
444+
* a problem in practice, especially if one is holding a share update
445+
* exclusive lock on the relation identified by name1. However, if choosing
446+
* multiple names within a single command, you'd better create the new object
447+
* and do CommandCounterIncrement before choosing the next one!
448+
*/
449+
static char *
450+
ChooseExtendedStatisticName(const char *name1, const char *name2,
451+
const char *label, Oid namespaceid)
452+
{
453+
int pass = 0;
454+
char *stxname = NULL;
455+
char modlabel[NAMEDATALEN];
456+
457+
/* try the unmodified label first */
458+
StrNCpy(modlabel, label, sizeof(modlabel));
459+
460+
for (;;)
461+
{
462+
Oid existingstats;
463+
464+
stxname = makeObjectName(name1, name2, modlabel);
465+
466+
existingstats = GetSysCacheOid2(STATEXTNAMENSP,
467+
PointerGetDatum(stxname),
468+
ObjectIdGetDatum(namespaceid));
469+
if (!OidIsValid(existingstats))
470+
break;
471+
472+
/* found a conflict, so try a new name component */
473+
pfree(stxname);
474+
snprintf(modlabel, sizeof(modlabel), "%s%d", label, ++pass);
475+
}
476+
477+
return stxname;
478+
}
479+
480+
/*
481+
* Generate "name2" for a new statistics given the list of column names for it
482+
* This will be passed to ChooseExtendedStatisticName along with the parent
483+
* table name and a suitable label.
484+
*
485+
* We know that less than NAMEDATALEN characters will actually be used,
486+
* so we can truncate the result once we've generated that many.
487+
*
488+
* XXX see also ChooseIndexNameAddition.
489+
*/
490+
static char *
491+
ChooseExtendedStatisticNameAddition(List *exprs)
492+
{
493+
char buf[NAMEDATALEN * 2];
494+
int buflen = 0;
495+
ListCell *lc;
496+
497+
buf[0] = '\0';
498+
foreach(lc, exprs)
499+
{
500+
ColumnRef *cref = (ColumnRef *) lfirst(lc);
501+
const char *name;
502+
503+
/* It should be one of these, but just skip if it happens not to be */
504+
if (!IsA(cref, ColumnRef))
505+
continue;
506+
507+
name = strVal((Value *) linitial(cref->fields));
508+
509+
if (buflen > 0)
510+
buf[buflen++] = '_'; /* insert _ between names */
511+
512+
/*
513+
* At this point we have buflen <= NAMEDATALEN. name should be less
514+
* than NAMEDATALEN already, but use strlcpy for paranoia.
515+
*/
516+
strlcpy(buf + buflen, name, NAMEDATALEN);
517+
buflen += strlen(buf + buflen);
518+
if (buflen >= NAMEDATALEN)
519+
break;
520+
}
521+
return pstrdup(buf);
522+
}

‎src/backend/nodes/copyfuncs.c

+1
Original file line numberDiff line numberDiff line change
@@ -3424,6 +3424,7 @@ _copyCreateStatsStmt(const CreateStatsStmt *from)
34243424
COPY_NODE_FIELD(stat_types);
34253425
COPY_NODE_FIELD(exprs);
34263426
COPY_NODE_FIELD(relations);
3427+
COPY_STRING_FIELD(stxcomment);
34273428
COPY_SCALAR_FIELD(if_not_exists);
34283429

34293430
return newnode;

‎src/backend/nodes/equalfuncs.c

+1
Original file line numberDiff line numberDiff line change
@@ -1363,6 +1363,7 @@ _equalCreateStatsStmt(const CreateStatsStmt *a, const CreateStatsStmt *b)
13631363
COMPARE_NODE_FIELD(stat_types);
13641364
COMPARE_NODE_FIELD(exprs);
13651365
COMPARE_NODE_FIELD(relations);
1366+
COMPARE_STRING_FIELD(stxcomment);
13661367
COMPARE_SCALAR_FIELD(if_not_exists);
13671368

13681369
return true;

‎src/backend/nodes/outfuncs.c

+1
Original file line numberDiff line numberDiff line change
@@ -2687,6 +2687,7 @@ _outCreateStatsStmt(StringInfo str, const CreateStatsStmt *node)
26872687
WRITE_NODE_FIELD(stat_types);
26882688
WRITE_NODE_FIELD(exprs);
26892689
WRITE_NODE_FIELD(relations);
2690+
WRITE_STRING_FIELD(stxcomment);
26902691
WRITE_BOOL_FIELD(if_not_exists);
26912692
}
26922693

‎src/backend/parser/gram.y

+5-2
Original file line numberDiff line numberDiff line change
@@ -3636,12 +3636,13 @@ TableLikeOptionList:
36363636
;
36373637

36383638
TableLikeOption:
3639-
DEFAULTS { $$ = CREATE_TABLE_LIKE_DEFAULTS; }
3639+
COMMENTS { $$ = CREATE_TABLE_LIKE_COMMENTS; }
36403640
| CONSTRAINTS { $$ = CREATE_TABLE_LIKE_CONSTRAINTS; }
3641+
| DEFAULTS { $$ = CREATE_TABLE_LIKE_DEFAULTS; }
36413642
| IDENTITY_P { $$ = CREATE_TABLE_LIKE_IDENTITY; }
36423643
| INDEXES { $$ = CREATE_TABLE_LIKE_INDEXES; }
3644+
| STATISTICS { $$ = CREATE_TABLE_LIKE_STATISTICS; }
36433645
| STORAGE { $$ = CREATE_TABLE_LIKE_STORAGE; }
3644-
| COMMENTS { $$ = CREATE_TABLE_LIKE_COMMENTS; }
36453646
| ALL { $$ = CREATE_TABLE_LIKE_ALL; }
36463647
;
36473648

@@ -3980,6 +3981,7 @@ CreateStatsStmt:
39803981
n->stat_types = $4;
39813982
n->exprs = $6;
39823983
n->relations = $8;
3984+
n->stxcomment = NULL;
39833985
n->if_not_exists = false;
39843986
$$ = (Node *)n;
39853987
}
@@ -3991,6 +3993,7 @@ CreateStatsStmt:
39913993
n->stat_types = $7;
39923994
n->exprs = $9;
39933995
n->relations = $11;
3996+
n->stxcomment = NULL;
39943997
n->if_not_exists = true;
39953998
$$ = (Node *)n;
39963999
}

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