diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/set_transaction.sgml | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/doc/src/sgml/ref/set_transaction.sgml b/doc/src/sgml/ref/set_transaction.sgml index 50a89088250..d57792ee3dd 100644 --- a/doc/src/sgml/ref/set_transaction.sgml +++ b/doc/src/sgml/ref/set_transaction.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_transaction.sgml,v 1.20 2004/08/12 21:00:22 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_transaction.sgml,v 1.21 2004/08/14 22:17:08 tgl Exp $ --> <refentry id="SQL-SET-TRANSACTION"> <refmeta> <refentrytitle id="SQL-SET-TRANSACTION-TITLE">SET TRANSACTION</refentrytitle> @@ -34,9 +34,9 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of: characteristics of the current transaction. It has no effect on any subsequent transactions. <command>SET SESSION CHARACTERISTICS</command> sets the default transaction - characteristics for subsequent transactions of a session. <command>SET - TRANSACTION</command> can override it for an individual - transaction. + characteristics for subsequent transactions of a session. These + defaults can be overridden by <command>SET TRANSACTION</command> for an + individual transaction. </para> <para> @@ -68,14 +68,6 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of: before the first query or data-modification statement was executed in this transaction. </para> - <tip> - <para> - Intuitively, serializable means that two concurrent - transactions will leave the database in the same state as if - the two had been executed strictly one after the other (in one - order or the other). - </para> - </tip> </listitem> </varlistentry> </variablelist> @@ -111,7 +103,7 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of: <literal>TRUNCATE</literal>; and <literal>EXPLAIN ANALYZE</literal> and <literal>EXECUTE</literal> if the command they would execute is among those listed. This is a high-level notion of read-only that - does not prevent writes to disk. + does not prevent all writes to disk. </para> </refsect1> @@ -138,8 +130,9 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of: and <xref linkend="guc-default-transaction-read-only">. (In fact <command>SET SESSION CHARACTERISTICS</command> is just a verbose equivalent for setting these variables with <command>SET</>.) - This allows them to be set in the configuration file. Consult <xref - linkend="runtime-config"> for more information. + This means the defaults can be set in the configuration file, via + <command>ALTER DATABASE</>, etc. Consult <xref linkend="runtime-config"> + for more information. </para> </refsect1> @@ -149,10 +142,10 @@ where <replaceable class="parameter">transaction_mode</replaceable> is one of: <para> Both commands are defined in the <acronym>SQL</acronym> standard. <literal>SERIALIZABLE</literal> is the default transaction - isolation level in the standard; in + isolation level in the standard. In <productname>PostgreSQL</productname> the default is ordinarily <literal>READ COMMITTED</literal>, but you can change it as - mentioned above. Because of multiversion concurrency control, the + mentioned above. Because of lack of predicate locking, the <literal>SERIALIZABLE</literal> level is not truly serializable. See <xref linkend="mvcc"> for details. </para> |