You are viewing a plain text version of this content. The canonical link for it is here.
Posted to derby-commits@db.apache.org by rh...@apache.org on 2011/06/30 17:23:32 UTC
svn commit: r1141568 - in /db/derby/docs/trunk/src/ref: crefproper22250.dita
refderby.ditamap rrefproperpreallocator.dita rrefsqlj37836.dita
rrefsqljcreatesequence.dita
Author: rhillegas
Date: Thu Jun 30 15:23:32 2011
New Revision: 1141568
URL: http://svn.apache.org/viewvc?rev=1141568&view=rev
Log:
DERBY-5307: Document the new derby.language.sequence.preallocator property.
Added:
db/derby/docs/trunk/src/ref/rrefproperpreallocator.dita (with props)
Modified:
db/derby/docs/trunk/src/ref/crefproper22250.dita
db/derby/docs/trunk/src/ref/refderby.ditamap
db/derby/docs/trunk/src/ref/rrefsqlj37836.dita
db/derby/docs/trunk/src/ref/rrefsqljcreatesequence.dita
Modified: db/derby/docs/trunk/src/ref/crefproper22250.dita
URL: http://svn.apache.org/viewvc/db/derby/docs/trunk/src/ref/crefproper22250.dita?rev=1141568&r1=1141567&r2=1141568&view=diff
==============================================================================
--- db/derby/docs/trunk/src/ref/crefproper22250.dita (original)
+++ db/derby/docs/trunk/src/ref/crefproper22250.dita Thu Jun 30 15:23:32 2011
@@ -193,6 +193,11 @@ about when changes to the property are d
<entry colname="3">Static</entry>
</row>
<row>
+<entry colname="1"><i><xref href="rrefproperpreallocator.dita#rrefproperpreallocator">derby.language.sequence.preallocator</xref></i></entry>
+<entry colname="2">S, D</entry>
+<entry colname="3">Static</entry>
+</row>
+<row>
<entry colname="1"><i><xref href="rrefproper10607.dita#rrefproper10607">derby.locks.deadlockTimeout</xref></i></entry>
<entry colname="2">S, D</entry>
<entry colname="3">Dynamic</entry>
Modified: db/derby/docs/trunk/src/ref/refderby.ditamap
URL: http://svn.apache.org/viewvc/db/derby/docs/trunk/src/ref/refderby.ditamap?rev=1141568&r1=1141567&r2=1141568&view=diff
==============================================================================
--- db/derby/docs/trunk/src/ref/refderby.ditamap (original)
+++ db/derby/docs/trunk/src/ref/refderby.ditamap Thu Jun 30 15:23:32 2011
@@ -750,6 +750,7 @@ URL syntax"></topicref>
</topicref>
<topicref href="rrefproper43517.dita" navtitle="derby.language.logStatementText">
</topicref>
+<topicref href="rrefproperpreallocator.dita" navtitle="derby.language.sequence.preallocator"></topicref>
<topicref href="rrefproper10607.dita" navtitle="derby.locks.deadlockTimeout">
</topicref>
<topicref href="rrefproper23835.dita" navtitle="derby.locks.deadlockTrace">
Added: db/derby/docs/trunk/src/ref/rrefproperpreallocator.dita
URL: http://svn.apache.org/viewvc/db/derby/docs/trunk/src/ref/rrefproperpreallocator.dita?rev=1141568&view=auto
==============================================================================
--- db/derby/docs/trunk/src/ref/rrefproperpreallocator.dita (added)
+++ db/derby/docs/trunk/src/ref/rrefproperpreallocator.dita Thu Jun 30 15:23:32 2011
@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+<!DOCTYPE reference PUBLIC "-//OASIS//DTD DITA Reference//EN" "../dtd/reference.dtd">
+<reference xml:lang="en-us" id="rrefproperpreallocator">
+<title>derby.language.sequence.preallocator</title>
+<prolog><metadata>
+<keywords><indexterm>derby.language.sequence.preallocator</indexterm>
+<indexterm>Sequence preallocation</indexterm>
+<indexterm>Identity preallocation</indexterm>
+</keywords>
+</metadata>
+</prolog><refbody>
+<section><title>Function</title>
+<p>Specifies how many values to preallocate for sequences and identity columns.</p>
+</section>
+<refsyn><title>Syntax</title>
+<codeblock><b>derby.language.sequence.preallocator=<i>number</i></b></codeblock>
+<p>
+or
+</p>
+<codeblock><b>derby.language.sequence.preallocator=<i>className</i></b></codeblock>
+<p>
+If set to a positive number, that is the number of values which
+<ph conref="../conrefs.dita#prod/productshortname"></ph>
+preallocates for each sequence and identity column.
+</p>
+<p>
+If set to a class name, that class must implement
+<i>org.apache.derby.catalog.SequencePreallocator</i>. The class
+customizes the size of the preallocation range for each sequence and
+identity column. For more information, see the public API javadoc for
+<i>org.apache.derby.catalog.SequencePreallocator</i>.
+</p>
+</refsyn>
+<section><title>Default</title>
+<p>20</p>
+<p>By default, <ph conref="../conrefs.dita#prod/productshortname"></ph> preallocates 20
+values for each sequence and identity column.</p>
+</section>
+<example><title>Example</title>
+<codeblock><b>derby.language.sequence.preallocator=50</b></codeblock>
+</example>
+<section><title>Scope</title>
+<p>
+<xref
+href="crefproper51399.dita#crefproper51399/rrefproper41229">system-wide</xref>,
+<xref href="crefproper51399.dita#crefproper51399/rrefproper15705">database-wide</xref>
+</p>
+</section>
+<section><title>Dynamic or static</title>
+<p>This property is semi-static; changing it while
+<ph conref="../conrefs.dita#prod/productshortname"></ph> is running
+will not affect sequences and identity columns which are already
+being used. However, the new value will be picked up by sequences and
+identity columns which weren't being used before the value was
+changed. In addition, DDL causes the old value to be forgotten. After
+performing DDL, the new value will be picked up by all sequences and
+identity columns.</p>
+</section></refbody></reference>
Propchange: db/derby/docs/trunk/src/ref/rrefproperpreallocator.dita
------------------------------------------------------------------------------
svn:eol-style = native
Modified: db/derby/docs/trunk/src/ref/rrefsqlj37836.dita
URL: http://svn.apache.org/viewvc/db/derby/docs/trunk/src/ref/rrefsqlj37836.dita?rev=1141568&r1=1141567&r2=1141568&view=diff
==============================================================================
--- db/derby/docs/trunk/src/ref/rrefsqlj37836.dita (original)
+++ db/derby/docs/trunk/src/ref/rrefsqlj37836.dita Thu Jun 30 15:23:32 2011
@@ -156,6 +156,19 @@ T2's insert, but T2 can see the value ca
level can see increment values generated by itself and previous nesting levels,
all the way to the top-level SQL statement that initiated the recursive triggers.
You can only have 16 levels of trigger recursion.</p> </section>
+
+<section>
+<title>Performance</title>
+<p>
+To boost performance and concurrency,
+<ph conref="../conrefs.dita#prod/productshortname"></ph>
+preallocates ranges of upcoming values for sequences and identity columns. The lengths of these ranges
+can be configured by adjusting the value of the
+<xref href="rrefproperpreallocator.dita#rrefproperpreallocator">derby.language.sequence.preallocator</xref>
+property.
+</p>
+</section>
+
<section><title>Example</title><codeblock>create table greetings
(i int generated by default as identity (START WITH 2, INCREMENT BY 1),
ch char(50));
Modified: db/derby/docs/trunk/src/ref/rrefsqljcreatesequence.dita
URL: http://svn.apache.org/viewvc/db/derby/docs/trunk/src/ref/rrefsqljcreatesequence.dita?rev=1141568&r1=1141567&r2=1141568&view=diff
==============================================================================
--- db/derby/docs/trunk/src/ref/rrefsqljcreatesequence.dita (original)
+++ db/derby/docs/trunk/src/ref/rrefsqljcreatesequence.dita Thu Jun 30 15:23:32 2011
@@ -87,6 +87,18 @@ exception when the generator wraps aroun
expression</xref>.
</p></section>
+<section>
+<title>Performance</title>
+<p>
+To boost performance and concurrency,
+<ph conref="../conrefs.dita#prod/productshortname"></ph>
+preallocates ranges of upcoming values for sequences and identity columns. The lengths of these ranges
+can be configured by adjusting the value of the
+<xref href="rrefproperpreallocator.dita#rrefproperpreallocator">derby.language.sequence.preallocator</xref>
+property.
+</p>
+</section>
+
<example><title>Examples</title>
<p>The following statement creates a sequence generator of type INT, with a
start value of -2147483648 (the smallest INT value). The value increases by 1,