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Overdue code review for ALTER SEQUENCE patch. Don't generate illegal Node
tree for CYCLE option; don't assume zeros are invalid values for sequence fields other than increment_by; don't reset cache_value when not told to; simplify code for testing whether to apply defaults.
1 parent b3d72d3 commit 1c5f223

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2 files changed

+68
-51
lines changed

2 files changed

+68
-51
lines changed

‎src/backend/commands/sequence.c

Lines changed: 65 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.103 2003/09/25 06:57:58 petere Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.104 2003/11/24 16:54:07 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -70,7 +70,7 @@ static SeqTable seqtab = NULL; /* Head of list of SeqTable items */
7070
static void init_sequence(RangeVar *relation,
7171
SeqTable *p_elm, Relation *p_rel);
7272
static Form_pg_sequence read_info(SeqTable elm, Relation rel, Buffer *buf);
73-
static void init_params(List *options, Form_pg_sequence new);
73+
static void init_params(List *options, Form_pg_sequence new, bool isInit);
7474
static void do_setval(RangeVar *sequence, int64 next, bool iscalled);
7575

7676
/*
@@ -94,16 +94,8 @@ DefineSequence(CreateSeqStmt *seq)
9494
int i;
9595
NameData name;
9696

97-
/* Values are NULL (or false) by default */
98-
new.last_value = 0;
99-
new.increment_by = 0;
100-
new.max_value = 0;
101-
new.min_value = 0;
102-
new.cache_value = 0;
103-
new.is_cycled = false;
104-
105-
/* Check and set values */
106-
init_params(seq->options, &new);
97+
/* Check and set all option values */
98+
init_params(seq->options, &new, true);
10799

108100
/*
109101
* Create relation (and fill *null & *value)
@@ -299,7 +291,7 @@ DefineSequence(CreateSeqStmt *seq)
299291
/*
300292
* AlterSequence
301293
*
302-
* Modify the defition of a sequence relation
294+
* Modify the definition of a sequence relation
303295
*/
304296
void
305297
AlterSequence(AlterSeqStmt *stmt)
@@ -314,7 +306,7 @@ AlterSequence(AlterSeqStmt *stmt)
314306
/* open and AccessShareLock sequence */
315307
init_sequence(stmt->sequence, &elm, &seqrel);
316308

317-
/* allow DROP to sequence owner only */
309+
/* allow ALTER to sequence owner only */
318310
if (!pg_class_ownercheck(elm->relid, GetUserId()))
319311
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
320312
stmt->sequence->relname);
@@ -323,16 +315,18 @@ AlterSequence(AlterSeqStmt *stmt)
323315
seq = read_info(elm, seqrel, &buf);
324316
page = BufferGetPage(buf);
325317

318+
/* copy old values of options */
326319
new.increment_by = seq->increment_by;
327320
new.max_value = seq->max_value;
328321
new.min_value = seq->min_value;
329322
new.cache_value = seq->cache_value;
330323
new.is_cycled = seq->is_cycled;
331324
new.last_value = seq->last_value;
332325

333-
/* Check and set values */
334-
init_params(stmt->options, &new);
326+
/* Check and set new values */
327+
init_params(stmt->options, &new, false);
335328

329+
/* Now okay to update the on-disk tuple */
336330
seq->increment_by = new.increment_by;
337331
seq->max_value = new.max_value;
338332
seq->min_value = new.min_value;
@@ -871,16 +865,22 @@ read_info(SeqTable elm, Relation rel, Buffer *buf)
871865
return seq;
872866
}
873867

874-
868+
/*
869+
* init_params: process the options list of CREATE or ALTER SEQUENCE,
870+
* and store the values into appropriate fields of *new.
871+
*
872+
* If isInit is true, fill any unspecified options with default values;
873+
* otherwise, do not change existing options that aren't explicitly overridden.
874+
*/
875875
static void
876-
init_params(List *options, Form_pg_sequence new)
876+
init_params(List *options, Form_pg_sequence new, bool isInit)
877877
{
878878
DefElem *last_value = NULL;
879879
DefElem *increment_by = NULL;
880880
DefElem *max_value = NULL;
881881
DefElem *min_value = NULL;
882882
DefElem *cache_value = NULL;
883-
bool is_cycled_set = false;
883+
DefElem *is_cycled = NULL;
884884
List *option;
885885

886886
foreach(option, options)
@@ -934,54 +934,65 @@ init_params(List *options, Form_pg_sequence new)
934934
}
935935
else if (strcmp(defel->defname, "cycle") == 0)
936936
{
937-
if (is_cycled_set)
937+
if (is_cycled)
938938
ereport(ERROR,
939939
(errcode(ERRCODE_SYNTAX_ERROR),
940940
errmsg("conflicting or redundant options")));
941-
is_cycled_set = true;
942-
new->is_cycled = (defel->arg != NULL);
941+
is_cycled = defel;
943942
}
944943
else
945944
elog(ERROR, "option \"%s\" not recognized",
946945
defel->defname);
947946
}
948947

949948
/* INCREMENT BY */
950-
if (new->increment_by == 0 && increment_by == (DefElem *) NULL)
951-
new->increment_by = 1;
952-
else if (increment_by != (DefElem *) NULL)
949+
if (increment_by != (DefElem *) NULL)
953950
{
954951
new->increment_by = defGetInt64(increment_by);
955952
if (new->increment_by == 0)
956953
ereport(ERROR,
957954
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
958955
errmsg("INCREMENT must not be zero")));
959956
}
957+
else if (isInit)
958+
new->increment_by = 1;
959+
960+
/* CYCLE */
961+
if (is_cycled != (DefElem *) NULL)
962+
{
963+
new->is_cycled = intVal(is_cycled->arg);
964+
Assert(new->is_cycled == false || new->is_cycled == true);
965+
}
966+
else if (isInit)
967+
new->is_cycled = false;
960968

961-
/* MAXVALUE */
962-
if ((new->max_value == 0 && max_value == (DefElem *) NULL)
963-
|| (max_value != (DefElem *) NULL && !max_value->arg))
969+
/* MAXVALUE (null arg means NO MAXVALUE) */
970+
if (max_value != (DefElem *) NULL && max_value->arg)
971+
{
972+
new->max_value = defGetInt64(max_value);
973+
}
974+
else if (isInit || max_value != (DefElem *) NULL)
964975
{
965976
if (new->increment_by > 0)
966977
new->max_value = SEQ_MAXVALUE; /* ascending seq */
967978
else
968-
new->max_value = -1; /* descending seq */
979+
new->max_value = -1; /* descending seq */
969980
}
970-
else if (max_value != (DefElem *) NULL)
971-
new->max_value = defGetInt64(max_value);
972981

973-
/* MINVALUE */
974-
if ((new->min_value == 0 && min_value == (DefElem *) NULL)
975-
|| (min_value != (DefElem *) NULL && !min_value->arg))
982+
/* MINVALUE (null arg means NO MINVALUE) */
983+
if (min_value != (DefElem *) NULL && min_value->arg)
984+
{
985+
new->min_value = defGetInt64(min_value);
986+
}
987+
else if (isInit || min_value != (DefElem *) NULL)
976988
{
977989
if (new->increment_by > 0)
978-
new->min_value = 1; /* ascending seq */
990+
new->min_value = 1; /* ascending seq */
979991
else
980992
new->min_value = SEQ_MINVALUE; /* descending seq */
981993
}
982-
else if (min_value != (DefElem *) NULL)
983-
new->min_value = defGetInt64(min_value);
984994

995+
/* crosscheck min/max */
985996
if (new->min_value >= new->max_value)
986997
{
987998
char bufm[100],
@@ -996,16 +1007,17 @@ init_params(List *options, Form_pg_sequence new)
9961007
}
9971008

9981009
/* START WITH */
999-
if (new->last_value == 0 && last_value == (DefElem *) NULL)
1010+
if (last_value != (DefElem *) NULL)
1011+
new->last_value = defGetInt64(last_value);
1012+
else if (isInit)
10001013
{
10011014
if (new->increment_by > 0)
10021015
new->last_value = new->min_value; /* ascending seq */
10031016
else
10041017
new->last_value = new->max_value; /* descending seq */
10051018
}
1006-
else if (last_value != (DefElem *) NULL)
1007-
new->last_value = defGetInt64(last_value);
10081019

1020+
/* crosscheck */
10091021
if (new->last_value < new->min_value)
10101022
{
10111023
char bufs[100],
@@ -1032,17 +1044,22 @@ init_params(List *options, Form_pg_sequence new)
10321044
}
10331045

10341046
/* CACHE */
1035-
if (cache_value == (DefElem *) NULL)
1036-
new->cache_value = 1;
1037-
else if ((new->cache_value = defGetInt64(cache_value)) <= 0)
1047+
if (cache_value != (DefElem *) NULL)
10381048
{
1039-
char buf[100];
1049+
new->cache_value = defGetInt64(cache_value);
1050+
if (new->cache_value <= 0)
1051+
{
1052+
char buf[100];
10401053

1041-
snprintf(buf, sizeof(buf), INT64_FORMAT, new->cache_value);
1042-
ereport(ERROR,
1043-
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1044-
errmsg("CACHE (%s) must be greater than zero", buf)));
1054+
snprintf(buf, sizeof(buf), INT64_FORMAT, new->cache_value);
1055+
ereport(ERROR,
1056+
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1057+
errmsg("CACHE (%s) must be greater than zero",
1058+
buf)));
1059+
}
10451060
}
1061+
else if (isInit)
1062+
new->cache_value = 1;
10461063
}
10471064

10481065

‎src/backend/parser/gram.y

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.438 2003/11/21 22:32:49 tgl Exp $
14+
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.439 2003/11/24 16:54:07 tgl Exp $
1515
*
1616
* HISTORY
1717
* AUTHOR DATE MAJOR EVENT
@@ -1926,11 +1926,11 @@ OptSeqElem: CACHE NumericOnly
19261926
}
19271927
| CYCLE
19281928
{
1929-
$$ = makeDefElem("cycle", (Node *)true);
1929+
$$ = makeDefElem("cycle", (Node *)makeInteger(TRUE));
19301930
}
19311931
| NO CYCLE
19321932
{
1933-
$$ = makeDefElem("cycle", (Node *)false);
1933+
$$ = makeDefElem("cycle", (Node *)makeInteger(FALSE));
19341934
}
19351935
| INCREMENT opt_by NumericOnly
19361936
{

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