Migrate the former contrib/txid module into core. This will make it easier

for Slony and Skytools to depend on it.  Per discussion.

doc/src/sgml/datatype.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.209 2007/08/31 04:52:29 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.210 2007/10/13 23:06:26 tgl Exp $ -->
 
  <chapter id="datatype">
   <title id="datatype-title">Data Types</title>
@@ -246,6 +246,12 @@
        <entry>full text search document</entry>
       </row>
 
+      <row>
+       <entry><type>txid_snapshot</type></entry>
+       <entry></entry>
+       <entry>user-level transaction ID snapshot</entry>
+      </row>
+
       <row>
        <entry><type>uuid</type></entry>
        <entry></entry>

doc/src/sgml/func.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.400 2007/10/11 02:43:55 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.401 2007/10/13 23:06:26 tgl Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -12048,6 +12048,84 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
     databases within each cluster and their descriptions are stored globally
     as well.
    </para>
+
+   <indexterm>
+    <primary>txid_current</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>txid_current_snapshot</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>txid_snapshot_xmin</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>txid_snapshot_xmax</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>txid_snapshot_xip</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>txid_visible_in_snapshot</primary>
+   </indexterm>
+
+   <para>
+    The functions shown in <xref linkend="functions-txid-snapshot">
+    export server internal transaction info to user level.
+   </para>
+
+   <table id="functions-txid-snapshot">
+    <title>Transaction IDs and snapshots</title>
+    <tgroup cols="3">
+     <thead>
+      <row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry></row>
+     </thead>
+
+     <tbody>
+      <row>
+       <entry><literal><function>txid_current</function>()</literal></entry>
+       <entry><type>bigint</type></entry>
+       <entry>get current transaction ID</entry>
+      </row>
+      <row>
+       <entry><literal><function>txid_current_snapshot</function>()</literal></entry>
+       <entry><type>txid_snapshot</type></entry>
+       <entry>get current snapshot</entry>
+      </row>
+      <row>
+       <entry><literal><function>txid_snapshot_xmin</function>(<parameter>txid_snapshot</parameter>)</literal></entry>
+       <entry><type>bigint</type></entry>
+       <entry>get xmin of snapshot</entry>
+      </row>
+      <row>
+       <entry><literal><function>txid_snapshot_xmax</function>(<parameter>txid_snapshot</parameter>)</literal></entry>
+       <entry><type>bigint</type></entry>
+       <entry>get xmax of snapshot</entry>
+      </row>
+      <row>
+       <entry><literal><function>txid_snapshot_xip</function>(<parameter>txid_snapshot</parameter>)</literal></entry>
+       <entry><type>setof bigint</type></entry>
+       <entry>get in-progress transaction IDs in snapshot</entry>
+      </row>
+      <row>
+       <entry><literal><function>txid_visible_in_snapshot</function>(<parameter>bigint</parameter>, <parameter>txid_snapshot</parameter>)</literal></entry>
+       <entry><type>boolean</type></entry>
+       <entry>is transaction ID visible in snapshot?</entry>
+      </row>
+     </tbody>
+    </tgroup>
+   </table>
+
+   <para>
+    The internal transaction ID type (<type>xid</>) is 32 bits wide and so
+    it wraps around every 4 billion transactions.  However, these functions
+    export a 64-bit format that is extended with an <quote>epoch</> counter
+    so that it will not wrap around for the life of an installation.
+   </para>
   </sect1>
 
  <sect1 id="functions-admin">

src/backend/utils/adt/Makefile

 #
 # Makefile for utils/adt
 #
-# $PostgreSQL: pgsql/src/backend/utils/adt/Makefile,v 1.67 2007/09/07 15:09:56 teodor Exp $
+# $PostgreSQL: pgsql/src/backend/utils/adt/Makefile,v 1.68 2007/10/13 23:06:26 tgl Exp $
 #
 
 subdir = src/backend/utils/adt
@@ -28,8 +28,8 @@ OBJS = acl.o arrayfuncs.o array_userfuncs.o arrayutils.o bool.o \
 	ascii.o quote.o pgstatfuncs.o encode.o dbsize.o genfile.o \
 	tsginidx.o tsgistidx.o tsquery.o tsquery_cleanup.o tsquery_gist.o \
 	tsquery_op.o tsquery_rewrite.o tsquery_util.o tsrank.o \
-	tsvector.o tsvector_op.o tsvector_parser.o\
-	uuid.o xml.o
+	tsvector.o tsvector_op.o tsvector_parser.o \
+	txid.o uuid.o xml.o
 
 like.o: like.c like_match.c
 

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.431 2007/10/13 20:18:41 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.432 2007/10/13 23:06:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200710131
+#define CATALOG_VERSION_NO	200710141
 
 #endif

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.473 2007/09/25 20:03:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.474 2007/10/13 23:06:26 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -4399,6 +4399,28 @@ DESCR("I/O");
 DATA(insert OID = 3774 (  regdictionarysend	PGNSP PGUID 12 1 0 f f t f i 1 17 "3769" _null_ _null_ _null_ regdictionarysend - _null_ _null_ ));
 DESCR("I/O");
 
+/* txid */
+DATA(insert OID = 2939 (  txid_snapshot_in			PGNSP PGUID 12 1  0 f f t f i 1 2970 "2275"	_null_ _null_ _null_ txid_snapshot_in - _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 2940 (  txid_snapshot_out			PGNSP PGUID 12 1  0 f f t f i 1 2275 "2970" _null_ _null_ _null_ txid_snapshot_out - _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 2941 (  txid_snapshot_recv		PGNSP PGUID 12 1  0 f f t f i 1 2970 "2281"	_null_ _null_ _null_ txid_snapshot_recv - _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 2942 (  txid_snapshot_send		PGNSP PGUID 12 1  0 f f t f i 1 17 "2970"	_null_ _null_ _null_ txid_snapshot_send - _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 2943 (  txid_current				PGNSP PGUID 12 1  0 f f t f s 0 20 ""		_null_ _null_ _null_ txid_current - _null_ _null_ ));
+DESCR("get current transaction ID");
+DATA(insert OID = 2944 (  txid_current_snapshot		PGNSP PGUID 12 1  0 f f t f s 0 2970 ""		_null_ _null_ _null_ txid_current_snapshot - _null_ _null_ ));
+DESCR("get current snapshot");
+DATA(insert OID = 2945 (  txid_snapshot_xmin		PGNSP PGUID 12 1  0 f f t f i 1 20 "2970"	_null_ _null_ _null_ txid_snapshot_xmin - _null_ _null_ ));
+DESCR("get xmin of snapshot");
+DATA(insert OID = 2946 (  txid_snapshot_xmax		PGNSP PGUID 12 1  0 f f t f i 1 20 "2970"	_null_ _null_ _null_ txid_snapshot_xmax - _null_ _null_ ));
+DESCR("get xmax of snapshot");
+DATA(insert OID = 2947 (  txid_snapshot_xip			PGNSP PGUID 12 1 50 f f t t i 1 20 "2970"	_null_ _null_ _null_ txid_snapshot_xip - _null_ _null_ ));
+DESCR("get set of in-progress txids in snapshot");
+DATA(insert OID = 2948 (  txid_visible_in_snapshot	PGNSP PGUID 12 1  0 f f t f i 2 16 "20 2970" _null_ _null_ _null_ txid_visible_in_snapshot - _null_ _null_ ));
+DESCR("is txid visible in snapshot?");
+
 
 /*
  * Symbolic values for provolatile column: these indicate whether the result

src/include/catalog/pg_type.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_type.h,v 1.188 2007/09/03 02:30:45 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_type.h,v 1.189 2007/10/13 23:06:27 tgl Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -572,6 +572,10 @@ DATA(insert OID = 3645 ( _tsquery		PGNSP PGUID -1 f b t \054 0	3615 0 array_in a
 DATA(insert OID = 3735 ( _regconfig		PGNSP PGUID -1 f b t \054 0 3734 0 array_in array_out array_recv array_send - - - i x f 0 -1 0 _null_ _null_ ));
 DATA(insert OID = 3770 ( _regdictionary	PGNSP PGUID -1 f b t \054 0 3769 0 array_in array_out array_recv array_send - - - i x f 0 -1 0 _null_ _null_ ));
 
+DATA(insert OID = 2970 ( txid_snapshot	PGNSP PGUID -1 f b t \054 0 0 2949 txid_snapshot_in txid_snapshot_out txid_snapshot_recv txid_snapshot_send - - - d x f 0 -1 0 _null_ _null_ ));
+DESCR("txid snapshot");
+DATA(insert OID = 2949 ( _txid_snapshot	PGNSP PGUID -1 f b t \054 0	2970 0 array_in array_out array_recv array_send - - - d x f 0 -1 0 _null_ _null_ ));
+
 /*
  * pseudo-types
  *

src/include/utils/builtins.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.304 2007/09/24 01:29:30 adunstan Exp $
+ * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.305 2007/10/13 23:06:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -938,14 +938,17 @@ extern Datum pg_advisory_unlock_int4(PG_FUNCTION_ARGS);
 extern Datum pg_advisory_unlock_shared_int4(PG_FUNCTION_ARGS);
 extern Datum pg_advisory_unlock_all(PG_FUNCTION_ARGS);
 
-/* access/transam/twophase.c */
-extern Datum pg_prepared_xact(PG_FUNCTION_ARGS);
-
-/* commands/prepare.c */
-extern Datum pg_prepared_statement(PG_FUNCTION_ARGS);
-
-/* utils/mmgr/portalmem.c */
-extern Datum pg_cursor(PG_FUNCTION_ARGS);
+/* txid.c */
+extern Datum txid_snapshot_in(PG_FUNCTION_ARGS);
+extern Datum txid_snapshot_out(PG_FUNCTION_ARGS);
+extern Datum txid_snapshot_recv(PG_FUNCTION_ARGS);
+extern Datum txid_snapshot_send(PG_FUNCTION_ARGS);
+extern Datum txid_current(PG_FUNCTION_ARGS);
+extern Datum txid_current_snapshot(PG_FUNCTION_ARGS);
+extern Datum txid_snapshot_xmin(PG_FUNCTION_ARGS);
+extern Datum txid_snapshot_xmax(PG_FUNCTION_ARGS);
+extern Datum txid_snapshot_xip(PG_FUNCTION_ARGS);
+extern Datum txid_visible_in_snapshot(PG_FUNCTION_ARGS);
 
 /* uuid.c */
 extern Datum uuid_in(PG_FUNCTION_ARGS);
@@ -961,4 +964,13 @@ extern Datum uuid_ne(PG_FUNCTION_ARGS);
 extern Datum uuid_cmp(PG_FUNCTION_ARGS);
 extern Datum uuid_hash(PG_FUNCTION_ARGS);
 
+/* access/transam/twophase.c */
+extern Datum pg_prepared_xact(PG_FUNCTION_ARGS);
+
+/* commands/prepare.c */
+extern Datum pg_prepared_statement(PG_FUNCTION_ARGS);
+
+/* utils/mmgr/portalmem.c */
+extern Datum pg_cursor(PG_FUNCTION_ARGS);
+
 #endif   /* BUILTINS_H */

src/test/regress/expected/txid.out

+-- txid_snapshot data type and related functions
+-- i/o
+select '12:13:'::txid_snapshot;
+ txid_snapshot 
+---------------
+ 12:13:
+(1 row)
+
+select '12:18:14,16'::txid_snapshot;
+ txid_snapshot 
+---------------
+ 12:18:14,16
+(1 row)
+
+-- errors
+select '31:12:'::txid_snapshot;
+ERROR:  invalid input for txid_snapshot: "31:12:"
+select '0:1:'::txid_snapshot;
+ERROR:  invalid input for txid_snapshot: "0:1:"
+select '12:13:0'::txid_snapshot;
+ERROR:  invalid input for txid_snapshot: "12:13:0"
+select '12:16:14,13'::txid_snapshot;
+ERROR:  invalid input for txid_snapshot: "12:16:14,13"
+select '12:16:14,14'::txid_snapshot;
+ERROR:  invalid input for txid_snapshot: "12:16:14,14"
+create temp table snapshot_test (
+	nr	integer,
+	snap	txid_snapshot
+);
+insert into snapshot_test values (1, '12:13:');
+insert into snapshot_test values (2, '12:20:13,15,18');
+insert into snapshot_test values (3, '100001:100009:100005,100007,100008');
+insert into snapshot_test values (4, '100:150:101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131');
+select snap from snapshot_test order by nr;
+                                                                snap                                                                 
+-------------------------------------------------------------------------------------------------------------------------------------
+ 12:13:
+ 12:20:13,15,18
+ 100001:100009:100005,100007,100008
+ 100:150:101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131
+(4 rows)
+
+select  txid_snapshot_xmin(snap),
+	txid_snapshot_xmax(snap),
+	txid_snapshot_xip(snap)
+from snapshot_test order by nr;
+ txid_snapshot_xmin | txid_snapshot_xmax | txid_snapshot_xip 
+--------------------+--------------------+-------------------
+                 12 |                 20 |                13
+                 12 |                 20 |                15
+                 12 |                 20 |                18
+             100001 |             100009 |            100005
+             100001 |             100009 |            100007
+             100001 |             100009 |            100008
+                100 |                150 |               101
+                100 |                150 |               102
+                100 |                150 |               103
+                100 |                150 |               104
+                100 |                150 |               105
+                100 |                150 |               106
+                100 |                150 |               107
+                100 |                150 |               108
+                100 |                150 |               109
+                100 |                150 |               110
+                100 |                150 |               111
+                100 |                150 |               112
+                100 |                150 |               113
+                100 |                150 |               114
+                100 |                150 |               115
+                100 |                150 |               116
+                100 |                150 |               117
+                100 |                150 |               118
+                100 |                150 |               119
+                100 |                150 |               120
+                100 |                150 |               121
+                100 |                150 |               122
+                100 |                150 |               123
+                100 |                150 |               124
+                100 |                150 |               125
+                100 |                150 |               126
+                100 |                150 |               127
+                100 |                150 |               128
+                100 |                150 |               129
+                100 |                150 |               130
+                100 |                150 |               131
+(37 rows)
+
+select id, txid_visible_in_snapshot(id, snap)
+from snapshot_test, generate_series(11, 21) id
+where nr = 2;
+ id | txid_visible_in_snapshot 
+----+--------------------------
+ 11 | t
+ 12 | t
+ 13 | f
+ 14 | t
+ 15 | f
+ 16 | t
+ 17 | t
+ 18 | f
+ 19 | t
+ 20 | f
+ 21 | f
+(11 rows)
+
+-- test bsearch
+select id, txid_visible_in_snapshot(id, snap)
+from snapshot_test, generate_series(90, 160) id
+where nr = 4;
+ id  | txid_visible_in_snapshot 
+-----+--------------------------
+  90 | t
+  91 | t
+  92 | t
+  93 | t
+  94 | t
+  95 | t
+  96 | t
+  97 | t
+  98 | t
+  99 | t
+ 100 | t
+ 101 | f
+ 102 | f
+ 103 | f
+ 104 | f
+ 105 | f
+ 106 | f
+ 107 | f
+ 108 | f
+ 109 | f
+ 110 | f
+ 111 | f
+ 112 | f
+ 113 | f
+ 114 | f
+ 115 | f
+ 116 | f
+ 117 | f
+ 118 | f
+ 119 | f
+ 120 | f
+ 121 | f
+ 122 | f
+ 123 | f
+ 124 | f
+ 125 | f
+ 126 | f
+ 127 | f
+ 128 | f
+ 129 | f
+ 130 | f
+ 131 | f
+ 132 | t
+ 133 | t
+ 134 | t
+ 135 | t
+ 136 | t
+ 137 | t
+ 138 | t
+ 139 | t
+ 140 | t
+ 141 | t
+ 142 | t
+ 143 | t
+ 144 | t
+ 145 | t
+ 146 | t
+ 147 | t
+ 148 | t
+ 149 | t
+ 150 | f
+ 151 | f
+ 152 | f
+ 153 | f
+ 154 | f
+ 155 | f
+ 156 | f
+ 157 | f
+ 158 | f
+ 159 | f
+ 160 | f
+(71 rows)
+
+-- test current values also
+select txid_current() >= txid_snapshot_xmin(txid_current_snapshot());
+ ?column? 
+----------
+ t
+(1 row)
+
+-- we can't assume current is always less than xmax, however
+select txid_visible_in_snapshot(txid_current(), txid_current_snapshot());
+ txid_visible_in_snapshot 
+--------------------------
+ f
+(1 row)
+
+-- test 64bitness
+select txid_snapshot '1000100010001000:1000100010001100:1000100010001012,1000100010001013';
+                            txid_snapshot                            
+---------------------------------------------------------------------
+ 1000100010001000:1000100010001100:1000100010001012,1000100010001013
+(1 row)
+
+select txid_visible_in_snapshot('1000100010001012', '1000100010001000:1000100010001100:1000100010001012,1000100010001013');
+ txid_visible_in_snapshot 
+--------------------------
+ f
+(1 row)
+
+select txid_visible_in_snapshot('1000100010001015', '1000100010001000:1000100010001100:1000100010001012,1000100010001013');
+ txid_visible_in_snapshot 
+--------------------------
+ t
+(1 row)
+
+-- test 64bit overflow
+SELECT txid_snapshot '1:9223372036854775807:3';
+      txid_snapshot      
+-------------------------
+ 1:9223372036854775807:3
+(1 row)
+
+SELECT txid_snapshot '1:9223372036854775808:3';
+ERROR:  invalid input for txid_snapshot: "1:9223372036854775808:3"

src/test/regress/parallel_schedule

 # ----------
-# $PostgreSQL: pgsql/src/test/regress/parallel_schedule,v 1.44 2007/09/11 11:54:42 teodor Exp $
+# $PostgreSQL: pgsql/src/test/regress/parallel_schedule,v 1.45 2007/10/13 23:06:27 tgl Exp $
 #
 # By convention, we put no more than twenty tests in any one parallel group;
 # this limits the number of connections needed to run the tests.
@@ -8,7 +8,7 @@
 # ----------
 # The first group of parallel tests
 # ----------
-test: boolean char name varchar text int2 int4 int8 oid float4 float8 bit numeric uuid enum
+test: boolean char name varchar text int2 int4 int8 oid float4 float8 bit numeric txid uuid enum
 
 # Depends on things setup during char, varchar and text
 test: strings

src/test/regress/serial_schedule

-# $PostgreSQL: pgsql/src/test/regress/serial_schedule,v 1.41 2007/09/11 11:54:42 teodor Exp $
+# $PostgreSQL: pgsql/src/test/regress/serial_schedule,v 1.42 2007/10/13 23:06:27 tgl Exp $
 # This should probably be in an order similar to parallel_schedule.
 test: boolean
 test: char
@@ -13,6 +13,7 @@ test: float4
 test: float8
 test: bit
 test: numeric
+test: txid
 test: uuid
 test: enum
 test: strings

src/test/regress/sql/txid.sql

+-- txid_snapshot data type and related functions
+
+-- i/o
+select '12:13:'::txid_snapshot;
+select '12:18:14,16'::txid_snapshot;
+
+-- errors
+select '31:12:'::txid_snapshot;
+select '0:1:'::txid_snapshot;
+select '12:13:0'::txid_snapshot;
+select '12:16:14,13'::txid_snapshot;
+select '12:16:14,14'::txid_snapshot;
+
+create temp table snapshot_test (
+	nr	integer,
+	snap	txid_snapshot
+);
+
+insert into snapshot_test values (1, '12:13:');
+insert into snapshot_test values (2, '12:20:13,15,18');
+insert into snapshot_test values (3, '100001:100009:100005,100007,100008');
+insert into snapshot_test values (4, '100:150:101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131');
+select snap from snapshot_test order by nr;
+
+select  txid_snapshot_xmin(snap),
+	txid_snapshot_xmax(snap),
+	txid_snapshot_xip(snap)
+from snapshot_test order by nr;
+
+select id, txid_visible_in_snapshot(id, snap)
+from snapshot_test, generate_series(11, 21) id
+where nr = 2;
+
+-- test bsearch
+select id, txid_visible_in_snapshot(id, snap)
+from snapshot_test, generate_series(90, 160) id
+where nr = 4;
+
+-- test current values also
+select txid_current() >= txid_snapshot_xmin(txid_current_snapshot());
+
+-- we can't assume current is always less than xmax, however
+
+select txid_visible_in_snapshot(txid_current(), txid_current_snapshot());
+
+-- test 64bitness
+
+select txid_snapshot '1000100010001000:1000100010001100:1000100010001012,1000100010001013';
+select txid_visible_in_snapshot('1000100010001012', '1000100010001000:1000100010001100:1000100010001012,1000100010001013');
+select txid_visible_in_snapshot('1000100010001015', '1000100010001000:1000100010001100:1000100010001012,1000100010001013');
+
+-- test 64bit overflow
+SELECT txid_snapshot '1:9223372036854775807:3';
+SELECT txid_snapshot '1:9223372036854775808:3';