Allow default transaction isolation level (a.k.a. set session

characteristics) to be set through GUC.

diff --git a/doc/src/sgml/ref/set_transaction.sgml b/doc/src/sgml/ref/set_transaction.sgml
index 488ee6ac31c1b08cd8083b11d5fdc58e3631a9a9..aa97b2f7d43e10c6aa61a4663433fd6ad0be22a4 100644 (file)
--- a/doc/src/sgml/ref/set_transaction.sgml
+++ b/doc/src/sgml/ref/set_transaction.sgml
@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_transaction.sgml,v 1.3 2000/11/24 20:16:38 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_transaction.sgml,v 1.4 2001/06/30 22:03:25 petere Exp $ -->
 <refentry id="SQL-SET-TRANSACTION">
  <docinfo>
   <date>2000-11-24</date>
@@ -74,6 +74,18 @@ SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL { READ COMMITTED | SE
   </para>
  </refsect1>
 
+ <refsect1>
+  <title>Notes</title>
+
+  <para>
+   The session default transaction isolation level can also be set
+   with the command <literal>SET default_transaction_isolation =
+   '<replaceable>value</replaceable>'</literal> and in the
+   configuration file.  Consult the <citetitle>Administrator's
+   Guide</citetitle> for more information.
+  </para>
+ </refsect1>
+
  <refsect1 id="R1-SQL-SET-TRANSACTION-3">
   <title>Compatibility</title>
 

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 730d031a0f98094422e0d109be5d9ddc939676bb..f73bddf354b8dd7b35c4dbff9c589a55a52f7d70 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.71 2001/06/30 21:15:57 darcy Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.72 2001/06/30 22:03:25 petere Exp $
 -->
 
 <Chapter Id="runtime">
@@ -996,6 +996,29 @@ env PGOPTIONS='-c geqo=off' psql
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <indexterm>
+       <primary>transaction isolation level</primary>
+      </indexterm>
+
+      <term>DEFAUL_TRANSACTION_ISOLATION (<type>string</type>)</term>
+      <listitem>
+       <para>
+        Each SQL transaction has an isolation level, which can be
+        either <quote>read committed</quote> or
+        <quote>serializable</quote>.  This parameter controls what the
+        isolation level of each new transaction is set to.  The
+        default is read committed.
+       </para>
+
+       <para>
+        Consult the <citetitle>PostgreSQL User's Guide</citetitle> and
+        the command <command>SET TRANSACTION</command> for more
+        information.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term>DYNAMIC_LIBRARY_PATH (<type>string</type>)</term>
       <listitem>
@@ -1051,9 +1074,9 @@ dynamic_library_path = '/usr/local/lib:/home/my_project/lib:$libdir:$libdir/cont
         will use the <function>fsync()</> system call in several
         places to make sure that updates are physically written to
         disk and do not hang around in the kernel buffer cache. This
-        increases the chance that a database installation will still
-        be usable after an operating system or hardware crash by a
-        large amount. (Crashes of the database server itself do
+        increases the chance by a large amount that a database
+        installation will still be usable after an operating system or
+        hardware crash.  (Crashes of the database server itself do
         <emphasis>not</> affect this consideration.)
        </para>
 

diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index dd94509a7f298db0b149199c23ef6a9d21337244..3d96ba18390c0139e8392e8ac0665e61ca265348 100644 (file)
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/commands/variable.c,v 1.50 2001/06/12 22:54:05 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/commands/variable.c,v 1.51 2001/06/30 22:03:25 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -46,9 +46,6 @@ static bool show_timezone(void);
 static bool reset_timezone(void);
 static bool parse_timezone(char *);
 
-static bool show_DefaultXactIsoLevel(void);
-static bool reset_DefaultXactIsoLevel(void);
-static bool parse_DefaultXactIsoLevel(char *);
 static bool show_XactIsoLevel(void);
 static bool reset_XactIsoLevel(void);
 static bool parse_XactIsoLevel(char *);
@@ -448,69 +445,6 @@ reset_timezone(void)
 
 /* SET TRANSACTION */
 
-static bool
-parse_DefaultXactIsoLevel(char *value)
-{
-#if 0
-       TransactionState s = CurrentTransactionState;
-
-#endif
-
-       if (value == NULL)
-       {
-               reset_DefaultXactIsoLevel();
-               return TRUE;
-       }
-
-#if 0
-       if (s->state != TRANS_DEFAULT)
-       {
-               elog(ERROR, "ALTER SESSION/SET TRANSACTION ISOLATION LEVEL"
-                        " can not be called within a transaction");
-               return TRUE;
-       }
-#endif
-
-       if (strcasecmp(value, "SERIALIZABLE") == 0)
-               DefaultXactIsoLevel = XACT_SERIALIZABLE;
-       else if (strcasecmp(value, "COMMITTED") == 0)
-               DefaultXactIsoLevel = XACT_READ_COMMITTED;
-       else
-               elog(ERROR, "Bad TRANSACTION ISOLATION LEVEL (%s)", value);
-
-       return TRUE;
-}
-
-static bool
-show_DefaultXactIsoLevel(void)
-{
-
-       if (DefaultXactIsoLevel == XACT_SERIALIZABLE)
-               elog(NOTICE, "Default TRANSACTION ISOLATION LEVEL is SERIALIZABLE");
-       else
-               elog(NOTICE, "Default TRANSACTION ISOLATION LEVEL is READ COMMITTED");
-       return TRUE;
-}
-
-static bool
-reset_DefaultXactIsoLevel(void)
-{
-#if 0
-       TransactionState s = CurrentTransactionState;
-
-       if (s->state != TRANS_DEFAULT)
-       {
-               elog(ERROR, "ALTER SESSION/SET TRANSACTION ISOLATION LEVEL"
-                        " can not be called within a transaction");
-               return TRUE;
-       }
-#endif
-
-       DefaultXactIsoLevel = XACT_READ_COMMITTED;
-
-       return TRUE;
-}
-
 static bool
 parse_XactIsoLevel(char *value)
 {
@@ -530,7 +464,7 @@ parse_XactIsoLevel(char *value)
 
        if (strcasecmp(value, "SERIALIZABLE") == 0)
                XactIsoLevel = XACT_SERIALIZABLE;
-       else if (strcasecmp(value, "COMMITTED") == 0)
+       else if (strcasecmp(value, "READ COMMITTED") == 0)
                XactIsoLevel = XACT_READ_COMMITTED;
        else
                elog(ERROR, "Bad TRANSACTION ISOLATION LEVEL (%s)", value);
@@ -711,8 +645,6 @@ SetPGVariable(const char *name, const char *value)
                parse_datestyle(mvalue);
        else if (strcasecmp(name, "timezone") == 0)
                parse_timezone(mvalue);
-       else if (strcasecmp(name, "DefaultXactIsoLevel") == 0)
-               parse_DefaultXactIsoLevel(mvalue);
        else if (strcasecmp(name, "XactIsoLevel") == 0)
                parse_XactIsoLevel(mvalue);
        else if (strcasecmp(name, "client_encoding") == 0)
@@ -737,8 +669,6 @@ GetPGVariable(const char *name)
                show_datestyle();
        else if (strcasecmp(name, "timezone") == 0)
                show_timezone();
-       else if (strcasecmp(name, "DefaultXactIsoLevel") == 0)
-               show_DefaultXactIsoLevel();
        else if (strcasecmp(name, "XactIsoLevel") == 0)
                show_XactIsoLevel();
        else if (strcasecmp(name, "client_encoding") == 0)
@@ -752,7 +682,6 @@ GetPGVariable(const char *name)
                ShowAllGUCConfig();
                show_datestyle();
                show_timezone();
-               show_DefaultXactIsoLevel();
                show_XactIsoLevel();
                show_client_encoding();
                show_server_encoding();
@@ -772,8 +701,6 @@ ResetPGVariable(const char *name)
                reset_datestyle();
        else if (strcasecmp(name, "timezone") == 0)
                reset_timezone();
-       else if (strcasecmp(name, "DefaultXactIsoLevel") == 0)
-               reset_DefaultXactIsoLevel();
        else if (strcasecmp(name, "XactIsoLevel") == 0)
                reset_XactIsoLevel();
        else if (strcasecmp(name, "client_encoding") == 0)
@@ -784,8 +711,6 @@ ResetPGVariable(const char *name)
                reset_random_seed();
        else if (strcasecmp(name, "all") == 0)
        {
-               reset_DefaultXactIsoLevel();
-               reset_XactIsoLevel();
                reset_random_seed();
                /* reset_server_encoding(); */
                reset_client_encoding();
@@ -793,7 +718,8 @@ ResetPGVariable(const char *name)
                reset_timezone();
 
                ResetAllOptions(false);
-       } else
+       }
+       else
                SetConfigOption(name, NULL,
                                                superuser() ? PGC_SUSET : PGC_USERSET,
                                                false);

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 3c7d526a7b8fddd868e4247bd80d1365e7f15b2e..cf518f3cadd691c7dd446af64747d98b81f94f39 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.232 2001/06/23 00:07:34 momjian Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.233 2001/06/30 22:03:25 petere Exp $
  *
  * HISTORY
  *       AUTHOR                        DATE                    MAJOR EVENT
@@ -752,7 +752,7 @@ VariableSetStmt:  SET ColId TO var_value
         | SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL opt_level
                                {
                                        VariableSetStmt *n = makeNode(VariableSetStmt);
-                                       n->name  = "DefaultXactIsoLevel";
+                                       n->name  = "default_transaction_isolation";
                                        n->value = $8;
                                        $$ = (Node *) n;
                                }
@@ -772,7 +772,7 @@ VariableSetStmt:  SET ColId TO var_value
                                }
                ;
 
-opt_level:  READ COMMITTED                                     { $$ = "committed"; }
+opt_level:  READ COMMITTED                                     { $$ = "read committed"; }
                | SERIALIZABLE                                          { $$ = "serializable"; }
                ;
 

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c38d98d391119ed9e9f315499135c8c939784cf7..96dc8399e1c4fce51444c9cb6198d1cb65346c14 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -4,7 +4,7 @@
  * Support for grand unified configuration scheme, including SET
  * command, configuration file, and command line options.
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.43 2001/06/27 23:31:39 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.44 2001/06/30 22:03:26 petere Exp $
  *
  * Copyright 2000 by PostgreSQL Global Development Group
  * Written by Peter Eisentraut <[email protected]>.
@@ -51,6 +51,11 @@ extern char *Syslog_ident;
 static bool check_facility(const char *facility);
 #endif
 
+static char *default_iso_level_string;
+
+static bool check_defaultxactisolevel(const char *value);
+static void assign_defaultxactisolevel(const char *value);
+
 /*
  * Debugging options
  */
@@ -355,6 +360,9 @@ static struct config_real
 static struct config_string
                        ConfigureNamesString[] =
 {
+       {"default_transaction_isolation", PGC_USERSET, &default_iso_level_string,
+        "read committed", check_defaultxactisolevel, assign_defaultxactisolevel},
+
        {"dynamic_library_path", PGC_SUSET, &Dynamic_library_path,
         "$libdir", NULL, NULL},
 
@@ -1092,3 +1100,25 @@ check_facility(const char *facility)
 }
 
 #endif
+
+
+
+static bool
+check_defaultxactisolevel(const char *value)
+{
+       return (strcasecmp(value, "read committed") == 0
+                       || strcasecmp(value, "serializable") == 0)
+               ? true : false;
+}
+
+
+static void
+assign_defaultxactisolevel(const char *value)
+{
+       if (strcasecmp(value, "serializable") == 0)
+               DefaultXactIsoLevel = XACT_SERIALIZABLE;
+       else if (strcasecmp(value, "read committed") == 0)
+               DefaultXactIsoLevel = XACT_READ_COMMITTED;
+       else
+               elog(ERROR, "bogus transaction isolation level");
+}

diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index a3042bee83d0f4a22a7865d870f78fc628317d1d..fad01e7f32efd2c8d6a28018f25c00f5a9acd8ec 100644 (file)
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -166,6 +166,7 @@
 #
 #      Misc
 #
+#default_transaction_isolation = 'read committed'
 #sql_inheritance = true
 #australian_timezones = false
 #deadlock_timeout = 1000