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[PATCH v2] Add CREATE SEQUENCE AS <data type> clause
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* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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^ permalink  raw  reply  [nested|flat] 57+ messages in thread

* [PATCH v2] Add CREATE SEQUENCE AS <data type> clause
@ 2016-09-08 16:00 Peter Eisentraut <[email protected]>
  0 siblings, 0 replies; 57+ messages in thread

From: Peter Eisentraut @ 2016-09-08 16:00 UTC (permalink / raw)

This stores a data type, required to be an integer type, with the
sequence.  The sequences min and max values default to the range
supported by the type, and they cannot be set to values exceeding that
range.  The internal implementation of the sequence is not affected.

Change the serial types to create sequences of the appropriate type.
This makes sure that the min and max values of the sequence for a serial
column match the range of values supported by the table column.  So the
sequence can no longer overflow the table column.

This also makes monitoring for sequence exhaustion/wraparound easier,
which currently requires various contortions to cross-reference the
sequences with the table columns they are used with.
---
 doc/src/sgml/information_schema.sgml          |  4 +-
 doc/src/sgml/ref/create_sequence.sgml         | 37 +++++++----
 src/backend/catalog/information_schema.sql    |  4 +-
 src/backend/commands/sequence.c               | 92 ++++++++++++++++++++++++--
 src/backend/parser/gram.y                     |  6 +-
 src/backend/parser/parse_utilcmd.c            |  2 +-
 src/bin/pg_dump/pg_dump.c                     | 94 +++++++++++++++++----------
 src/bin/pg_dump/t/002_pg_dump.pl              |  2 +
 src/include/catalog/pg_proc.h                 |  2 +-
 src/include/commands/sequence.h               |  6 +-
 src/include/pg_config_manual.h                |  6 --
 src/test/modules/test_pg_dump/t/001_base.pl   |  1 +
 src/test/regress/expected/sequence.out        | 45 +++++++++----
 src/test/regress/expected/sequence_1.out      | 45 +++++++++----
 src/test/regress/expected/updatable_views.out |  3 +-
 src/test/regress/sql/sequence.sql             | 20 +++++-
 16 files changed, 269 insertions(+), 100 deletions(-)

diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..a3a19ce 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -4653,9 +4653,7 @@ <title><literal>sequences</literal> Columns</title>
       <entry><literal>data_type</literal></entry>
       <entry><type>character_data</type></entry>
       <entry>
-       The data type of the sequence.  In
-       <productname>PostgreSQL</productname>, this is currently always
-       <literal>bigint</literal>.
+       The data type of the sequence.
       </entry>
      </row>
 
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 62ae379..f31b595 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -21,7 +21,9 @@
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
+CREATE [ TEMPORARY | TEMP ] SEQUENCE [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable>
+    [ AS <replaceable class="parameter">data_type</replaceable> ]
+    [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
     [ OWNED BY { <replaceable class="parameter">table_name</replaceable>.<replaceable class="parameter">column_name</replaceable> | NONE } ]
@@ -111,6 +113,21 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><replaceable class="parameter">data_type</replaceable></term>
+    <listitem>
+     <para>
+      The optional
+      clause <literal>AS <replaceable class="parameter">data_type</replaceable></literal>
+      specifies the data type of the sequence.  Valid types are
+      are <literal>smallint</literal>, <literal>integer</literal>,
+      and <literal>bigint</literal>.  <literal>bigint</literal> is the
+      default.  The data type determines the default minimum and maximum
+      values of the sequence.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><replaceable class="parameter">increment</replaceable></term>
     <listitem>
      <para>
@@ -132,9 +149,9 @@ <title>Parameters</title>
       class="parameter">minvalue</replaceable></literal> determines
       the minimum value a sequence can generate. If this clause is not
       supplied or <option>NO MINVALUE</option> is specified, then
-      defaults will be used.  The defaults are 1 and
-      -2<superscript>63</>-1 for ascending and descending sequences,
-      respectively.
+      defaults will be used.  The default for an ascending sequence is 1.  The
+      default for a descending sequence is the minimum value of the data type
+      plus 1.
      </para>
     </listitem>
    </varlistentry>
@@ -148,9 +165,9 @@ <title>Parameters</title>
       class="parameter">maxvalue</replaceable></literal> determines
       the maximum value for the sequence. If this clause is not
       supplied or <option>NO MAXVALUE</option> is specified, then
-      default values will be used.  The defaults are
-      2<superscript>63</>-1 and -1 for ascending and descending
-      sequences, respectively.
+      default values will be used.  The default for an ascending sequence is
+      the maximum value of the data type.  The default for a descending
+      sequence is -1.
      </para>
     </listitem>
    </varlistentry>
@@ -349,12 +366,6 @@ <title>Compatibility</title>
    <itemizedlist>
     <listitem>
      <para>
-      The standard's <literal>AS <replaceable>data_type</></literal> expression is not
-      supported.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
       Obtaining the next value is done using the <function>nextval()</>
       function instead of the standard's <command>NEXT VALUE FOR</command>
       expression.
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..73a183e 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1531,8 +1531,8 @@ CREATE VIEW sequences AS
     SELECT CAST(current_database() AS sql_identifier) AS sequence_catalog,
            CAST(nc.nspname AS sql_identifier) AS sequence_schema,
            CAST(c.relname AS sql_identifier) AS sequence_name,
-           CAST('bigint' AS character_data) AS data_type,
-           CAST(64 AS cardinal_number) AS numeric_precision,
+           CAST(format_type(p.data_type, null) AS character_data) AS data_type,
+           CAST(CASE format_type(p.data_type, null) WHEN 'bigint' THEN 64 WHEN 'integer' THEN 32 WHEN 'smallint' THEN 16 END AS cardinal_number) AS numeric_precision,
            CAST(2 AS cardinal_number) AS numeric_precision_radix,
            CAST(0 AS cardinal_number) AS numeric_scale,
            CAST(p.start_value AS character_data) AS start_value,
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index fc3a8ee..1b1e261 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -31,6 +31,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
+#include "parser/parse_type.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/smgr.h"
@@ -212,6 +213,11 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 				coldef->colname = "log_cnt";
 				value[i - 1] = Int64GetDatum((int64) 0);
 				break;
+			case SEQ_COL_TYPE:
+				coldef->typeName = makeTypeNameFromOid(REGTYPEOID, -1);
+				coldef->colname = "sequence_type";
+				value[i - 1] = ObjectIdGetDatum(new.sequence_type);
+				break;
 			case SEQ_COL_CYCLE:
 				coldef->typeName = makeTypeNameFromOid(BOOLOID, -1);
 				coldef->colname = "is_cycled";
@@ -1166,6 +1172,7 @@ static void
 init_params(ParseState *pstate, List *options, bool isInit,
 			Form_pg_sequence new, List **owned_by)
 {
+	DefElem    *as_type = NULL;
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
 	DefElem    *increment_by = NULL;
@@ -1181,7 +1188,15 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	{
 		DefElem    *defel = (DefElem *) lfirst(option);
 
-		if (strcmp(defel->defname, "increment") == 0)
+		if (strcmp(defel->defname, "as") == 0)
+		{
+			if (as_type)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			as_type = defel;
+		}
+		else if (strcmp(defel->defname, "increment") == 0)
 		{
 			if (increment_by)
 				ereport(ERROR,
@@ -1265,6 +1280,23 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (isInit)
 		new->log_cnt = 0;
 
+	/* AS type */
+	if (as_type != NULL)
+	{
+		if (!isInit)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("sequence data type cannot be changed")));
+
+		new->sequence_type = typenameTypeId(NULL, defGetTypeName(as_type));
+		if (new->sequence_type != INT2OID && new->sequence_type != INT4OID && new->sequence_type != INT8OID)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("sequence type must be smallint, integer, or bigint")));
+	}
+	else if (isInit)
+		new->sequence_type = INT8OID;
+
 	/* INCREMENT BY */
 	if (increment_by != NULL)
 	{
@@ -1292,12 +1324,34 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (max_value != NULL && max_value->arg)
 	{
 		new->max_value = defGetInt64(max_value);
+
+		if ((new->sequence_type == INT2OID && new->max_value > PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->max_value > PG_INT32_MAX))
+		{
+			char		bufx[100];
+
+			snprintf(bufx, sizeof(bufx), INT64_FORMAT, new->max_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MAXVALUE (%s) is too large for sequence data type %s",
+						bufx, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || max_value != NULL)
 	{
 		if (new->increment_by > 0)
-			new->max_value = SEQ_MAXVALUE;		/* ascending seq */
+		{
+			/* ascending seq */
+			if (new->sequence_type == INT2OID)
+				new->max_value = PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->max_value = PG_INT32_MAX;
+			else
+				new->max_value = PG_INT64_MAX;
+		}
 		else
 			new->max_value = -1;	/* descending seq */
 		new->log_cnt = 0;
@@ -1307,6 +1361,20 @@ init_params(ParseState *pstate, List *options, bool isInit,
 	if (min_value != NULL && min_value->arg)
 	{
 		new->min_value = defGetInt64(min_value);
+
+		if ((new->sequence_type == INT2OID && new->min_value < -PG_INT16_MAX)
+			|| (new->sequence_type == INT4OID && new->min_value < -PG_INT32_MAX))
+		{
+			char		bufm[100];
+
+			snprintf(bufm, sizeof(bufm), INT64_FORMAT, new->min_value);
+
+			ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("MINVALUE (%s) is too large for sequence data type %s",
+						bufm, format_type_be(new->sequence_type))));
+		}
+
 		new->log_cnt = 0;
 	}
 	else if (isInit || min_value != NULL)
@@ -1314,7 +1382,16 @@ init_params(ParseState *pstate, List *options, bool isInit,
 		if (new->increment_by > 0)
 			new->min_value = 1; /* ascending seq */
 		else
-			new->min_value = SEQ_MINVALUE;		/* descending seq */
+		{
+			/* descending seq */
+			/* We use the _MAX constants for symmetry. */
+			if (new->sequence_type == INT2OID)
+				new->min_value = -PG_INT16_MAX;
+			else if (new->sequence_type == INT4OID)
+				new->min_value = -PG_INT32_MAX;
+			else
+				new->min_value = -PG_INT64_MAX;
+		}
 		new->log_cnt = 0;
 	}
 
@@ -1534,8 +1611,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 {
 	Oid			relid = PG_GETARG_OID(0);
 	TupleDesc	tupdesc;
-	Datum		values[5];
-	bool		isnull[5];
+	Datum		values[6];
+	bool		isnull[6];
 	SeqTable	elm;
 	Relation	seqrel;
 	Buffer		buf;
@@ -1551,7 +1628,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 				 errmsg("permission denied for sequence %s",
 						RelationGetRelationName(seqrel))));
 
-	tupdesc = CreateTemplateTupleDesc(5, false);
+	tupdesc = CreateTemplateTupleDesc(6, false);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value",
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value",
@@ -1562,6 +1639,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option",
 					   BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data_type",
+					   OIDOID, -1, 0);
 
 	BlessTupleDesc(tupdesc);
 
@@ -1574,6 +1653,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS)
 	values[2] = Int64GetDatum(seq->max_value);
 	values[3] = Int64GetDatum(seq->increment_by);
 	values[4] = BoolGetDatum(seq->is_cycled);
+	values[5] = ObjectIdGetDatum(seq->sequence_type);
 
 	UnlockReleaseBuffer(buf);
 	relation_close(seqrel, NoLock);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 1526c73..db99751 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3634,7 +3634,11 @@ SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
 
-SeqOptElem: CACHE NumericOnly
+SeqOptElem: AS SimpleTypename
+				{
+					$$ = makeDefElem("as", (Node *)$2, @1);
+				}
+			| CACHE NumericOnly
 				{
 					$$ = makeDefElem("cache", (Node *)$2, @1);
 				}
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 7a2950e..bc68367 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -456,7 +456,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		seqstmt = makeNode(CreateSeqStmt);
 		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
+		seqstmt->options = list_make1(makeDefElem("as", (Node *) SystemTypeName(column->typeName->typeOid == INT2OID ? "int2" : (column->typeName->typeOid == INT4OID ? "int4" : "int8")), -1));
 
 		/*
 		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ba9c276..2d5d012 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16329,12 +16329,12 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	PGresult   *res;
 	char	   *startv,
 			   *incby,
-			   *maxv = NULL,
-			   *minv = NULL,
-			   *cache;
-	char		bufm[100],
-				bufx[100];
+			   *maxv,
+			   *minv,
+			   *cache,
+			   *seqtype;
 	bool		cycled;
+	bool		is_ascending;
 	PQExpBuffer query = createPQExpBuffer();
 	PQExpBuffer delqry = createPQExpBuffer();
 	PQExpBuffer labelq = createPQExpBuffer();
@@ -16342,41 +16342,28 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, tbinfo->dobj.namespace->dobj.name);
 
-	snprintf(bufm, sizeof(bufm), INT64_FORMAT, SEQ_MINVALUE);
-	snprintf(bufx, sizeof(bufx), INT64_FORMAT, SEQ_MAXVALUE);
-
-	if (fout->remoteVersion >= 80400)
+	if (fout->remoteVersion >= 100000)
+	{
+		appendPQExpBuffer(query,
+						  "SELECT sequence_name, "
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, sequence_type FROM %s",
+						  fmtId(tbinfo->dobj.name));
+	}
+	else if (fout->remoteVersion >= 80400)
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 	else
 	{
 		appendPQExpBuffer(query,
 						  "SELECT sequence_name, "
-						  "0 AS start_value, increment_by, "
-				   "CASE WHEN increment_by > 0 AND max_value = %s THEN NULL "
-				   "     WHEN increment_by < 0 AND max_value = -1 THEN NULL "
-						  "     ELSE max_value "
-						  "END AS max_value, "
-					"CASE WHEN increment_by > 0 AND min_value = 1 THEN NULL "
-				   "     WHEN increment_by < 0 AND min_value = %s THEN NULL "
-						  "     ELSE min_value "
-						  "END AS min_value, "
-						  "cache_value, is_cycled FROM %s",
-						  bufx, bufm,
+						  "0 AS start_value, increment_by, max_value, min_value, "
+						  "cache_value, is_cycled, 'bigint'::name AS sequence_type FROM %s",
 						  fmtId(tbinfo->dobj.name));
 	}
 
@@ -16403,12 +16390,46 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 
 	startv = PQgetvalue(res, 0, 1);
 	incby = PQgetvalue(res, 0, 2);
-	if (!PQgetisnull(res, 0, 3))
-		maxv = PQgetvalue(res, 0, 3);
-	if (!PQgetisnull(res, 0, 4))
-		minv = PQgetvalue(res, 0, 4);
+	maxv = PQgetvalue(res, 0, 3);
+	minv = PQgetvalue(res, 0, 4);
 	cache = PQgetvalue(res, 0, 5);
 	cycled = (strcmp(PQgetvalue(res, 0, 6), "t") == 0);
+	seqtype = PQgetvalue(res, 0, 7);
+
+	is_ascending = incby[0] != '-';
+
+	if (is_ascending && atoi(minv) == 1)
+		minv = NULL;
+	if (!is_ascending && atoi(maxv) == -1)
+		maxv = NULL;
+
+	if (strcmp(seqtype, "smallint") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT16_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT16_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "integer") == 0)
+	{
+		if (!is_ascending && atoi(minv) == -PG_INT32_MAX)
+			minv = NULL;
+		if (is_ascending && atoi(maxv) == PG_INT32_MAX)
+			maxv = NULL;
+	}
+	else if (strcmp(seqtype, "bigint") == 0)
+	{
+		char		bufm[100],
+					bufx[100];
+
+		snprintf(bufm, sizeof(bufm), INT64_FORMAT, -PG_INT64_MAX);
+		snprintf(bufx, sizeof(bufx), INT64_FORMAT, PG_INT64_MAX);
+
+		if (!is_ascending && strcmp(minv, bufm) == 0)
+			minv = NULL;
+		if (is_ascending && strcmp(maxv, bufx) == 0)
+			maxv = NULL;
+	}
 
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
@@ -16432,6 +16453,9 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "CREATE SEQUENCE %s\n",
 					  fmtId(tbinfo->dobj.name));
 
+	if (strcmp(seqtype, "bigint") != 0)
+		appendPQExpBuffer(query, "    AS %s\n", seqtype);
+
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
 
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 37cbdcd..2d72232 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1965,6 +1965,7 @@
 	'CREATE SEQUENCE test_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
@@ -1995,6 +1996,7 @@
 	'CREATE SEQUENCE test_third_table_col1_seq' => {
 		regexp => qr/^
 			\QCREATE SEQUENCE test_third_table_col1_seq\E
+			\n\s+\QAS integer\E
 			\n\s+\QSTART WITH 1\E
 			\n\s+\QINCREMENT BY 1\E
 			\n\s+\QNO MINVALUE\E
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..9c7fd42 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1766,7 +1766,7 @@ DATA(insert OID = 1576 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20
 DESCR("set sequence value");
 DATA(insert OID = 1765 (  setval			PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ ));
 DESCR("set sequence value and is_called status");
-DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
+DATA(insert OID = 3078 (  pg_sequence_parameters	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,26}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,data_type}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_));
 DESCR("sequence parameters, for use by information schema");
 
 DATA(insert OID = 1579 (  varbit_in			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ ));
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 392a626..54c24b7 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -32,6 +32,7 @@ typedef struct FormData_pg_sequence
 	int64		min_value;
 	int64		cache_value;
 	int64		log_cnt;
+	Oid			sequence_type;
 	bool		is_cycled;
 	bool		is_called;
 } FormData_pg_sequence;
@@ -50,8 +51,9 @@ typedef FormData_pg_sequence *Form_pg_sequence;
 #define SEQ_COL_MINVALUE		6
 #define SEQ_COL_CACHE			7
 #define SEQ_COL_LOG				8
-#define SEQ_COL_CYCLE			9
-#define SEQ_COL_CALLED			10
+#define SEQ_COL_TYPE			9
+#define SEQ_COL_CYCLE			10
+#define SEQ_COL_CALLED			11
 
 #define SEQ_COL_FIRSTCOL		SEQ_COL_NAME
 #define SEQ_COL_LASTCOL			SEQ_COL_CALLED
diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index a2b2b61..d2b99fb 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -46,12 +46,6 @@
 #define INDEX_MAX_KEYS		32
 
 /*
- * Set the upper and lower bounds of sequence values.
- */
-#define SEQ_MAXVALUE	PG_INT64_MAX
-#define SEQ_MINVALUE	(-SEQ_MAXVALUE)
-
-/*
  * When we don't have native spinlocks, we use semaphores to simulate them.
  * Decreasing this value reduces consumption of OS resources; increasing it
  * may improve performance, but supplying a real spinlock implementation is
diff --git a/src/test/modules/test_pg_dump/t/001_base.pl b/src/test/modules/test_pg_dump/t/001_base.pl
index 55f0eb4..a6e0efb 100644
--- a/src/test/modules/test_pg_dump/t/001_base.pl
+++ b/src/test/modules/test_pg_dump/t/001_base.pl
@@ -226,6 +226,7 @@
 	'CREATE SEQUENCE regress_pg_dump_table_col1_seq' => {
 		regexp => qr/^
                     \QCREATE SEQUENCE regress_pg_dump_table_col1_seq\E
+                    \n\s+\QAS integer\E
                     \n\s+\QSTART WITH 1\E
                     \n\s+\QINCREMENT BY 1\E
                     \n\s+\QNO MINVALUE\E
diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out
index 4ffbe92..1141d5c 100644
--- a/src/test/regress/expected/sequence.out
+++ b/src/test/regress/expected/sequence.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      31 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out
index 05da2bf..d5ecbf8 100644
--- a/src/test/regress/expected/sequence_1.out
+++ b/src/test/regress/expected/sequence_1.out
@@ -1,3 +1,19 @@
+--
+-- CREATE SEQUENCE
+--
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+ERROR:  sequence type must be smallint, integer, or bigint
+CREATE SEQUENCE sequence_testx AS foo;
+ERROR:  type "foo" does not exist
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+ERROR:  sequence data type cannot be changed
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+ERROR:  MAXVALUE (100000) is too large for sequence data type smallint
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+ERROR:  MINVALUE (-100000) is too large for sequence data type smallint
 ---
 --- test creation of SERIAL column
 ---
@@ -173,9 +189,9 @@ DROP SEQUENCE sequence_test;
 CREATE SEQUENCE foo_seq;
 ALTER TABLE foo_seq RENAME TO foo_seq_new;
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | f         | f
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          1 |           1 |            1 | 9223372036854775807 |         1 |           1 |       0 | bigint        | f         | f
 (1 row)
 
 SELECT nextval('foo_seq_new');
@@ -191,9 +207,9 @@ SELECT nextval('foo_seq_new');
 (1 row)
 
 SELECT * FROM foo_seq_new;
- sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | is_cycled | is_called 
----------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+-----------+-----------
- foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | f         | t
+ sequence_name | last_value | start_value | increment_by |      max_value      | min_value | cache_value | log_cnt | sequence_type | is_cycled | is_called 
+---------------+------------+-------------+--------------+---------------------+-----------+-------------+---------+---------------+-----------+-----------
+ foo_seq       |          2 |           1 |            1 | 9223372036854775807 |         1 |           1 |      32 | bigint        | f         | t
 (1 row)
 
 DROP SEQUENCE foo_seq_new;
@@ -301,19 +317,22 @@ SELECT nextval('sequence_test2');
 (1 row)
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
  sequence_catalog | sequence_schema |   sequence_name    | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value |    maximum_value    | increment | cycle_option 
 ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+--------------
  regression       | public          | sequence_test2     | bigint    |                64 |                       2 |             0 | 32          | 5             | 36                  | 4         | YES
- regression       | public          | serialtest2_f2_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f3_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
- regression       | public          | serialtest2_f4_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | sequence_test3     | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | sequence_test4     | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | sequence_test5     | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
+ regression       | public          | serialtest2_f2_seq | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+ regression       | public          | serialtest2_f3_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
+ regression       | public          | serialtest2_f4_seq | smallint  |                16 |                       2 |             0 | 1           | 1             | 32767               | 1         | NO
  regression       | public          | serialtest2_f5_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
  regression       | public          | serialtest2_f6_seq | bigint    |                64 |                       2 |             0 | 1           | 1             | 9223372036854775807 | 1         | NO
-(6 rows)
+ regression       | public          | serialtest_f2_foo  | integer   |                32 |                       2 |             0 | 1           | 1             | 2147483647          | 1         | NO
+(10 rows)
 
 -- Test comments
 COMMENT ON SEQUENCE asdf IS 'won''t work';
diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index f60991e..1b451e5 100644
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -107,6 +107,7 @@ SELECT table_name, column_name, is_updatable
  ro_view19  | min_value     | NO
  ro_view19  | cache_value   | NO
  ro_view19  | log_cnt       | NO
+ ro_view19  | sequence_type | NO
  ro_view19  | is_cycled     | NO
  ro_view19  | is_called     | NO
  ro_view2   | a             | NO
@@ -134,7 +135,7 @@ SELECT table_name, column_name, is_updatable
  rw_view16  | a             | YES
  rw_view16  | b             | YES
  rw_view16  | aa            | YES
-(46 rows)
+(47 rows)
 
 -- Read-only views
 DELETE FROM ro_view1;
diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql
index 98a2e7d..897d918 100644
--- a/src/test/regress/sql/sequence.sql
+++ b/src/test/regress/sql/sequence.sql
@@ -1,3 +1,18 @@
+--
+-- CREATE SEQUENCE
+--
+
+CREATE SEQUENCE sequence_test3 AS integer;
+CREATE SEQUENCE sequence_test4 AS smallint;
+CREATE SEQUENCE sequence_test5 AS bigint;
+CREATE SEQUENCE sequence_testx AS text;
+CREATE SEQUENCE sequence_testx AS foo;
+
+ALTER SEQUENCE sequence_test3 AS bigint;  -- fail
+
+CREATE SEQUENCE sequence_testx AS smallint MAXVALUE 100000;
+CREATE SEQUENCE sequence_testx AS smallint MINVALUE -100000;
+
 ---
 --- test creation of SERIAL column
 ---
@@ -139,9 +154,8 @@ CREATE SEQUENCE sequence_test2 START WITH 32;
 SELECT nextval('sequence_test2');
 
 -- Information schema
-SELECT * FROM information_schema.sequences WHERE sequence_name IN
-  ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq',
-   'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq')
+SELECT * FROM information_schema.sequences
+  WHERE sequence_name ~ ANY(ARRAY['sequence_test', 'serialtest'])
   ORDER BY sequence_name ASC;
 
 -- Test comments
-- 
2.10.0


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