Skip to content
Projects
Groups
Snippets
Help
Loading...
Help
Support
Keyboard shortcuts
?
Submit feedback
Contribute to GitLab
Sign in
Toggle navigation
P
Postgres FD Implementation
Project overview
Project overview
Details
Activity
Releases
Repository
Repository
Files
Commits
Branches
Tags
Contributors
Graph
Compare
Issues
0
Issues
0
List
Boards
Labels
Milestones
Merge Requests
0
Merge Requests
0
CI / CD
CI / CD
Pipelines
Jobs
Schedules
Analytics
Analytics
CI / CD
Repository
Value Stream
Wiki
Wiki
Snippets
Snippets
Members
Members
Collapse sidebar
Close sidebar
Activity
Graph
Create a new issue
Jobs
Commits
Issue Boards
Open sidebar
Abuhujair Javed
Postgres FD Implementation
Commits
3b6afdd7
Commit
3b6afdd7
authored
May 11, 2007
by
Neil Conway
Browse files
Options
Browse Files
Download
Email Patches
Plain Diff
Improvements to the SGML docs for TRUNCATE and CLUSTER.
parent
bc8036fc
Changes
2
Hide whitespace changes
Inline
Side-by-side
Showing
2 changed files
with
34 additions
and
31 deletions
+34
-31
doc/src/sgml/ref/cluster.sgml
doc/src/sgml/ref/cluster.sgml
+2
-2
doc/src/sgml/ref/truncate.sgml
doc/src/sgml/ref/truncate.sgml
+32
-29
No files found.
doc/src/sgml/ref/cluster.sgml
View file @
3b6afdd7
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/cluster.sgml,v 1.4
2 2007/04/08 02:07:35 tgl
Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/cluster.sgml,v 1.4
3 2007/05/11 19:40:07 neilc
Exp $
PostgreSQL documentation
-->
...
...
@@ -45,7 +45,7 @@ CLUSTER
not clustered. That is, no attempt is made to store new or
updated rows according to their index order. (If one wishes, one can
periodically recluster by issuing the command again. Also, setting
the table's
FILLFACTOR
storage parameter to less than 100% can aid
the table's
<literal>FILLFACTOR</literal>
storage parameter to less than 100% can aid
in preserving cluster ordering during updates, since updated rows
are preferentially kept on the same page.)
</para>
...
...
doc/src/sgml/ref/truncate.sgml
View file @
3b6afdd7
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/truncate.sgml,v 1.2
3 2007/04/07 17:12:15 tgl
Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/truncate.sgml,v 1.2
4 2007/05/11 19:40:08 neilc
Exp $
PostgreSQL documentation
-->
...
...
@@ -31,9 +31,9 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
<command>TRUNCATE</command> quickly removes all rows from a set of
tables. It has the same effect as an unqualified
<command>DELETE</command> on each table, but since it does not actually
scan the tables it is faster
; furthermore
it reclaims disk space
immediately, rather than requiring a subsequent
vacuum operation.
This is most useful on large tables.
scan the tables it is faster
. Furthermore,
it reclaims disk space
immediately, rather than requiring a subsequent
<command>VACUUM</command>
operation.
This is most useful on large tables.
</para>
</refsect1>
...
...
@@ -86,35 +86,38 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
in the same command. Checking validity in such cases would require table
scans, and the whole point is not to do one. The <literal>CASCADE</>
option can be used to automatically include all dependent tables —
but be very careful when using this option, else you might lose data you
but be very careful when using this option,
or
else you might lose data you
did not intend to!
</para>
<para>
<command>TRUNCATE</> will not run any
user-defined <literal>ON
DELETE</literal>
triggers that might exist for the tables.
<command>TRUNCATE</> will not run any
<literal>ON DELETE</literal>
triggers that might exist for the tables.
</para>
<para>
<command>TRUNCATE</> is not MVCC-safe (see <xref linkend="mvcc">
for general information about MVCC). After truncation, the table
will appear empty to all concurrent transactions, even if they are
using a snapshot taken before the truncation occurred. This will
only be an issue for a transaction that did not touch the table
before the truncation started — any transaction that has done
so would hold at least <literal>ACCESS SHARE</literal> lock,
which would block
<command>TRUNCATE</> until that transaction completes. So
truncation will not cause any apparent inconsistency in the table
contents for successive queries on the same table, but it could
cause visible inconsistency between the contents of the
truncated table and other tables.
</para>
<para>
<command>TRUNCATE</> is transaction-safe, however: the truncation
will roll back if the surrounding transaction does not commit.
</para>
<warning>
<para>
<command>TRUNCATE</> is not MVCC-safe (see <xref linkend="mvcc">
for general information about MVCC). After truncation, the table
will appear empty to all concurrent transactions, even if they
are using a snapshot taken before the truncation occurred. This
will only be an issue for a transaction that did not access the
truncated table before the truncation happened — any
transaction that has done so would hold at least an
<literal>ACCESS SHARE</literal> lock, which would block
<command>TRUNCATE</> until that transaction completes. So
truncation will not cause any apparent inconsistency in the table
contents for successive queries on the same table, but it could
cause visible inconsistency between the contents of the truncated
table and other tables in the database.
</para>
<para>
<command>TRUNCATE</> is transaction-safe, however: the truncation
will be safely rolled back if the surrounding transaction does not
commit.
</para>
</warning>
</refsect1>
<refsect1>
...
...
@@ -124,13 +127,13 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
Truncate the tables <literal>bigtable</literal> and <literal>fattable</literal>:
<programlisting>
TRUNCATE
TABLE
bigtable, fattable;
TRUNCATE bigtable, fattable;
</programlisting>
</para>
<para>
Truncate the table <literal>othertable</literal>, and cascade to any tables
that
are referencing
<literal>othertable</literal> via foreign-key
that
reference
<literal>othertable</literal> via foreign-key
constraints:
<programlisting>
...
...
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment