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-rw-r--r--doc/src/sgml/ref/alter_sequence.sgml29
-rw-r--r--src/backend/commands/sequence.c80
2 files changed, 59 insertions, 50 deletions
diff --git a/doc/src/sgml/ref/alter_sequence.sgml b/doc/src/sgml/ref/alter_sequence.sgml
index 31e64dac35d..7cf69e9ea3f 100644
--- a/doc/src/sgml/ref/alter_sequence.sgml
+++ b/doc/src/sgml/ref/alter_sequence.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/alter_sequence.sgml,v 1.20 2008/05/16 23:36:04 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/alter_sequence.sgml,v 1.21 2008/05/17 01:20:39 tgl Exp $
PostgreSQL documentation
-->
@@ -26,7 +26,9 @@ PostgreSQL documentation
<synopsis>
ALTER SEQUENCE <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
[ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
- [ RESTART [ [ WITH ] <replaceable class="parameter">start</replaceable> ] ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
+ [ START [ WITH ] <replaceable class="parameter">start</replaceable> ]
+ [ RESTART [ [ WITH ] <replaceable class="parameter">restart</replaceable> ] ]
+ [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
[ OWNED BY { <replaceable class="parameter">table</replaceable>.<replaceable class="parameter">column</replaceable> | NONE } ]
ALTER SEQUENCE <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
ALTER SEQUENCE <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
@@ -112,15 +114,29 @@ ALTER SEQUENCE <replaceable class="parameter">name</replaceable> SET SCHEMA <rep
<term><replaceable class="parameter">start</replaceable></term>
<listitem>
<para>
+ The optional clause <literal>START WITH <replaceable
+ class="parameter">start</replaceable></literal> changes the
+ recorded start value of the sequence. This has no effect on the
+ <emphasis>current</> sequence value; it simply sets the value
+ that future <command>ALTER SEQUENCE RESTART</> commands will use.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">restart</replaceable></term>
+ <listitem>
+ <para>
The optional clause <literal>RESTART [ WITH <replaceable
- class="parameter">start</replaceable> ]</literal> changes the
+ class="parameter">restart</replaceable> ]</literal> changes the
current value of the sequence. This is equivalent to calling the
<function>setval</> function with <literal>is_called</literal> =
<literal>false</>: the specified value will be returned by the
<emphasis>next</> call of <function>nextval</>.
Writing <literal>RESTART</> with no <replaceable
- class="parameter">start</replaceable> value is equivalent to supplying
- the start value used when the sequence was created.
+ class="parameter">restart</> value is equivalent to supplying
+ the start value that was recorded by <command>CREATE SEQUENCE</>
+ or last set by <command>ALTER SEQUENCE START WITH</>.
</para>
</listitem>
</varlistentry>
@@ -261,7 +277,8 @@ ALTER SEQUENCE serial RESTART WITH 105;
<para>
<command>ALTER SEQUENCE</command> conforms to the <acronym>SQL</acronym>
- standard, except for the <literal>OWNED BY</>, <literal>RENAME</>, and
+ standard, except for the <literal>START WITH</>,
+ <literal>OWNED BY</>, <literal>RENAME</>, and
<literal>SET SCHEMA</literal> clauses, which are
<productname>PostgreSQL</productname> extensions.
</para>
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 748413ebed3..5d5a3a243c4 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.151 2008/05/16 23:36:04 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.152 2008/05/17 01:20:39 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -91,7 +91,7 @@ static Relation open_share_lock(SeqTable seq);
static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
static Form_pg_sequence read_info(SeqTable elm, Relation rel, Buffer *buf);
static void init_params(List *options, bool isInit,
- Form_pg_sequence new, Form_pg_sequence old, List **owned_by);
+ Form_pg_sequence new, List **owned_by);
static void do_setval(Oid relid, int64 next, bool iscalled);
static void process_owned_by(Relation seqrel, List *owned_by);
@@ -119,7 +119,7 @@ DefineSequence(CreateSeqStmt *seq)
NameData name;
/* Check and set all option values */
- init_params(seq->options, true, &new, NULL, &owned_by);
+ init_params(seq->options, true, &new, &owned_by);
/*
* Create relation (and fill value[] and null[] for the tuple)
@@ -357,8 +357,11 @@ AlterSequenceInternal(Oid relid, List *options)
seq = read_info(elm, seqrel, &buf);
page = BufferGetPage(buf);
- /* Fill workspace with appropriate new info */
- init_params(options, false, &new, seq, &owned_by);
+ /* Copy old values of options into workspace */
+ memcpy(&new, seq, sizeof(FormData_pg_sequence));
+
+ /* Check and set new values */
+ init_params(options, false, &new, &owned_by);
/* Clear local cache so that we don't think we have cached numbers */
/* Note that we do not change the currval() state */
@@ -989,9 +992,10 @@ read_info(SeqTable elm, Relation rel, Buffer *buf)
*/
static void
init_params(List *options, bool isInit,
- Form_pg_sequence new, Form_pg_sequence old, List **owned_by)
+ Form_pg_sequence new, List **owned_by)
{
- DefElem *last_value = NULL;
+ DefElem *start_value = NULL;
+ DefElem *restart_value = NULL;
DefElem *increment_by = NULL;
DefElem *max_value = NULL;
DefElem *min_value = NULL;
@@ -1001,12 +1005,6 @@ init_params(List *options, bool isInit,
*owned_by = NIL;
- /* Copy old values of options into workspace */
- if (old != NULL)
- memcpy(new, old, sizeof(FormData_pg_sequence));
- else
- memset(new, 0, sizeof(FormData_pg_sequence));
-
foreach(option, options)
{
DefElem *defel = (DefElem *) lfirst(option);
@@ -1021,27 +1019,19 @@ init_params(List *options, bool isInit,
}
else if (strcmp(defel->defname, "start") == 0)
{
- if (!isInit)
- ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("use RESTART not START in ALTER SEQUENCE")));
- if (last_value)
+ if (start_value)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
- last_value = defel;
+ start_value = defel;
}
else if (strcmp(defel->defname, "restart") == 0)
{
- if (isInit)
- ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("use START not RESTART in CREATE SEQUENCE")));
- if (last_value)
+ if (restart_value)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options")));
- last_value = defel;
+ restart_value = defel;
}
else if (strcmp(defel->defname, "maxvalue") == 0)
{
@@ -1145,30 +1135,15 @@ init_params(List *options, bool isInit,
bufm, bufx)));
}
- /* START/RESTART [WITH] */
- if (last_value != NULL)
- {
- if (last_value->arg != NULL)
- new->last_value = defGetInt64(last_value);
- else
- {
- Assert(old != NULL);
- new->last_value = old->start_value;
- }
- if (isInit)
- new->start_value = new->last_value;
- new->is_called = false;
- new->log_cnt = 1;
- }
+ /* START WITH */
+ if (start_value != NULL)
+ new->start_value = defGetInt64(start_value);
else if (isInit)
{
if (new->increment_by > 0)
new->start_value = new->min_value; /* ascending seq */
else
new->start_value = new->max_value; /* descending seq */
- new->last_value = new->start_value;
- new->is_called = false;
- new->log_cnt = 1;
}
/* crosscheck START */
@@ -1197,7 +1172,24 @@ init_params(List *options, bool isInit,
bufs, bufm)));
}
- /* must crosscheck RESTART separately */
+ /* RESTART [WITH] */
+ if (restart_value != NULL)
+ {
+ if (restart_value->arg != NULL)
+ new->last_value = defGetInt64(restart_value);
+ else
+ new->last_value = new->start_value;
+ new->is_called = false;
+ new->log_cnt = 1;
+ }
+ else if (isInit)
+ {
+ new->last_value = new->start_value;
+ new->is_called = false;
+ new->log_cnt = 1;
+ }
+
+ /* crosscheck RESTART (or current value, if changing MIN/MAX) */
if (new->last_value < new->min_value)
{
char bufs[100],
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-04 11:08:00 +0000