Updates to reflect availability of autocommit option.

diff --git a/doc/src/sgml/ref/begin.sgml b/doc/src/sgml/ref/begin.sgml
index 850bfd77e68c98ec6884418bca6db0cff37d3fea..11ca82e6d49fd1a10fbef839e3b9683ddb156c66 100644 (file)
--- a/doc/src/sgml/ref/begin.sgml
+++ b/doc/src/sgml/ref/begin.sgml
@@ -1,5 +1,5 @@
 
 
@@ -103,33 +103,35 @@ WARNING:  BEGIN: already a transaction in progress
    BEGIN initiates a user transaction in chained mode,
    i.e., all user statements after BEGIN command will
    be executed in a single transaction until an explicit 
-   ,
-   ,
-   or execution abort. Statements in chained mode are executed much faster, 
+    or
+   .
+   Statements are executed more quickly in chained mode,
    because transaction start/commit requires significant CPU and disk 
    activity. Execution of multiple statements inside a transaction
-   is also required for consistency when changing several
-   related tables.
+   is also useful to ensure consistency when changing several
+   related tables: other clients will be unable to see the intermediate
+   states wherein not all the related updates have been done.
   
 
   
    The default transaction isolation level in
    PostgreSQL
-   is READ COMMITTED, where queries inside the transaction see only changes
-   committed before query execution. So, you have to use 
+   is READ COMMITTED, wherein each query inside the transaction sees changes
+   committed before that query begins execution. So, you have to use 
    SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
-   just after BEGIN if you need more rigorous transaction isolation. 
+   just after BEGIN if you need more rigorous transaction
+   isolation.  (Alternatively, you can change the default transaction
+   isolation level; see the PostgreSQL Administrator's
+   Guide for details.)
    In SERIALIZABLE mode queries will see only changes committed before
    the entire
    transaction began (actually, before execution of the first DML statement
-   in a serializable transaction).
+   in the transaction).
   
 
   
-   If the transaction is committed, PostgreSQL 
-   will ensure either that all updates are done or else that none of
-   them are done. Transactions have the standard ACID
-   (atomic, consistent, isolatable, and durable) property.
+   Transactions have the standard ACID
+   (atomic, consistent, isolatable, and durable) properties.
   
   
   
@@ -140,9 +142,9 @@ WARNING:  BEGIN: already a transaction in progress
     Notes
    
    
-    Refer to 
-    for further information
-    about locking tables inside a transaction.
+    
+    endterm="sql-start-transaction-title"> has the same functionality
+    as BEGIN.
    
    
    
@@ -151,6 +153,17 @@ WARNING:  BEGIN: already a transaction in progress
     
     to terminate a transaction.
    
+
+   
+    Refer to 
+    for further information
+    about locking tables inside a transaction.
+   
+   
+   
+    If you turn autocommit mode off, then BEGIN
+    is not required: any SQL command automatically starts a transaction.
+   
   
  
 


diff --git a/doc/src/sgml/ref/start_transaction.sgml b/doc/src/sgml/ref/start_transaction.sgml

index 2e657c610bbe569ba5c9982344352ac34a4bf373..fb8dd1319322a6e2074583b8b3af49c9b9bb265c 100644 (file)

--- a/doc/src/sgml/ref/start_transaction.sgml
+++ b/doc/src/sgml/ref/start_transaction.sgml
@@ -1,4 +1,8 @@
-
+
+
 
  
   2002-07-26
@@ -76,7 +80,7 @@ WARNING:  BEGIN: already a transaction in progress
    This command begins a new transaction. If the isolation level is
    specified, the new transaction has that isolation level. In all other
    respects, the behavior of this command is identical to the
-   <command>BEGIN> command.
+   <xref linkend="sql-begin" endterm="sql-begin-title"> command.
   
 
  
@@ -87,8 +91,8 @@ WARNING:  BEGIN: already a transaction in progress
   
    The isolation level of a transaction can also be set with the 
    linkend="sql-set-transaction" endterm="sql-set-transaction-title">
-   command. If no isolation level is specified, the level defaults to
-   READ COMMITTED.
+   command. If no isolation level is specified, the default isolation
+   level is used.
   
  
 
@@ -99,11 +103,14 @@ WARNING:  BEGIN: already a transaction in progress
    SQL99
 
    
-    SERIALIZABLE is the default level in
-    SQL. PostgreSQL
+    SERIALIZABLE is the default isolation level in
+    SQL99, but it is not the usual default in
+    PostgreSQL: the factory default setting
+    is READ COMMITTED.
+    PostgreSQL 
     does not provide the isolation levels READ UNCOMMITTED
-    and REPEATABLE READ. Because of multiversion
-    concurrency control, the SERIALIZABLE level is
+    and REPEATABLE READ. Because of lack of predicate
+    locking, the SERIALIZABLE level is
     not truly serializable. See the User's Guide
     for details.
    

diff --git a/doc/src/sgml/ref/start_transaction.sgml b/doc/src/sgml/ref/start_transaction.sgml
index 2e657c610bbe569ba5c9982344352ac34a4bf373..fb8dd1319322a6e2074583b8b3af49c9b9bb265c 100644 (file)
--- a/doc/src/sgml/ref/start_transaction.sgml
+++ b/doc/src/sgml/ref/start_transaction.sgml
@@ -1,4 +1,8 @@
-
+
+
 
  
   2002-07-26
@@ -76,7 +80,7 @@ WARNING:  BEGIN: already a transaction in progress
    This command begins a new transaction. If the isolation level is
    specified, the new transaction has that isolation level. In all other
    respects, the behavior of this command is identical to the
-   <command>BEGIN> command.
+   <xref linkend="sql-begin" endterm="sql-begin-title"> command.
   
 
  
@@ -87,8 +91,8 @@ WARNING:  BEGIN: already a transaction in progress
   
    The isolation level of a transaction can also be set with the 
    linkend="sql-set-transaction" endterm="sql-set-transaction-title">
-   command. If no isolation level is specified, the level defaults to
-   READ COMMITTED.
+   command. If no isolation level is specified, the default isolation
+   level is used.
   
  
 
@@ -99,11 +103,14 @@ WARNING:  BEGIN: already a transaction in progress
    SQL99
 
    
-    SERIALIZABLE is the default level in
-    SQL. PostgreSQL
+    SERIALIZABLE is the default isolation level in
+    SQL99, but it is not the usual default in
+    PostgreSQL: the factory default setting
+    is READ COMMITTED.
+    PostgreSQL 
     does not provide the isolation levels READ UNCOMMITTED
-    and REPEATABLE READ. Because of multiversion
-    concurrency control, the SERIALIZABLE level is
+    and REPEATABLE READ. Because of lack of predicate
+    locking, the SERIALIZABLE level is
     not truly serializable. See the User's Guide
     for details.