1- <!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_transaction.sgml,v 1.20 2004/08/12 21:00:22 tgl Exp $ -->
1+ <!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_transaction.sgml,v 1.21 2004/08/14 22:17:08 tgl Exp $ -->
22<refentry id="SQL-SET-TRANSACTION">
33 <refmeta>
44 <refentrytitle id="SQL-SET-TRANSACTION-TITLE">SET TRANSACTION</refentrytitle>
@@ -34,9 +34,9 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of:
3434 characteristics of the current transaction. It has no effect on any
3535 subsequent transactions. <command>SET SESSION
3636 CHARACTERISTICS</command> sets the default transaction
37- characteristics for subsequent transactions of a session.<command>SET
38- TRANSACTION</command>can override it for an individual
39- transaction.
37+ characteristics for subsequent transactions of a session.These
38+ defaults can be overridden by <command>SET TRANSACTION</command> for an
39+ individual transaction.
4040 </para>
4141
4242 <para>
@@ -68,14 +68,6 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of:
6868 before the first query or data-modification statement was executed in
6969 this transaction.
7070 </para>
71- <tip>
72- <para>
73- Intuitively, serializable means that two concurrent
74- transactions will leave the database in the same state as if
75- the two had been executed strictly one after the other (in one
76- order or the other).
77- </para>
78- </tip>
7971 </listitem>
8072 </varlistentry>
8173 </variablelist>
@@ -111,7 +103,7 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of:
111103 <literal>TRUNCATE</literal>; and <literal>EXPLAIN ANALYZE</literal>
112104 and <literal>EXECUTE</literal> if the command they would execute is
113105 among those listed. This is a high-level notion of read-only that
114- does not prevent writes to disk.
106+ does not preventall writes to disk.
115107 </para>
116108 </refsect1>
117109
@@ -138,8 +130,9 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of:
138130 and <xref linkend="guc-default-transaction-read-only">.
139131 (In fact <command>SET SESSION CHARACTERISTICS</command> is just a
140132 verbose equivalent for setting these variables with <command>SET</>.)
141- This allows them to be set in the configuration file. Consult <xref
142- linkend="runtime-config"> for more information.
133+ This means the defaults can be set in the configuration file, via
134+ <command>ALTER DATABASE</>, etc. Consult <xref linkend="runtime-config">
135+ for more information.
143136 </para>
144137 </refsect1>
145138
@@ -149,10 +142,10 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of:
149142 <para>
150143 Both commands are defined in the <acronym>SQL</acronym> standard.
151144 <literal>SERIALIZABLE</literal> is the default transaction
152- isolation level in the standard; in
145+ isolation level in the standard. In
153146 <productname>PostgreSQL</productname> the default is ordinarily
154147 <literal>READ COMMITTED</literal>, but you can change it as
155- mentioned above. Because ofmultiversion concurrency control , the
148+ mentioned above. Because oflack of predicate locking , the
156149 <literal>SERIALIZABLE</literal> level is not truly
157150 serializable. See <xref linkend="mvcc"> for details.
158151 </para>