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Posted to commits@isis.apache.org by da...@apache.org on 2017/10/09 10:34:01 UTC
[03/10] isis-site git commit: ISIS-1465: updates docs,
hint-n-tip for DN 4.x and structure of simpleapp
http://git-wip-us.apache.org/repos/asf/isis-site/blob/346e91e1/content/guides/ugodn/ugodn.html
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diff --git a/content/guides/ugodn/ugodn.html b/content/guides/ugodn/ugodn.html
index 92ad846..198a5aa 100644
--- a/content/guides/ugodn/ugodn.html
+++ b/content/guides/ugodn/ugodn.html
@@ -1751,6 +1751,160 @@ isis.persistor.datanucleus.impl.javax.jdo.option.ConnectionPassword=</code></pre
</table>
</div>
</div>
+ <div class="sect2">
+ <h3 id="_ugodn_hints-and-tips_diagnosing-n-plus-1">5.4. Diagnosing n+1 Issues</h3>
+ <div class="btn-group" style="float: right; font-size: small; padding: 6px; margin-top: -55px; ">
+ <button type="button" class="btn btn-xs btn-default" onclick="window.location.href="https://github.com/apache/isis/edit/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_diagnosing-n-plus-1.adoc""><i class="fa fa-pencil-square-o"></i> Edit</button>
+ <button type="button" class="btn btn-xs btn-default dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"><span class="caret"></span><span class="sr-only">Toggle Dropdown</span></button>
+ <ul class="dropdown-menu">
+ <li><a href="https://github.com/apache/isis/edit/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_diagnosing-n-plus-1.adoc" target="_blank"><i class="fa fa-pencil-square-o fa-fw" aria-hidden="true"></i> Edit</a></li>
+ <li><a href="https://github.com/apache/isis/commits/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_diagnosing-n-plus-1.adoc" target="_blank"><i class="fa fa-clock-o fa-fw" aria-hidden="true"></i> History</a></li>
+ <li><a href="https://github.com/apache/isis/raw/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_diagnosing-n-plus-1.adoc" target="_blank"><i class="fa fa-file-text-o fa-fw" aria-hidden="true"></i> Raw</a></li>
+ <li><a href="https://github.com/apache/isis/blame/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_diagnosing-n-plus-1.adoc" target="_blank"><i class="fa fa-hand-o-right fa-fw" aria-hidden="true"></i> Blame</a></li>
+ </ul>
+ </div>
+ <div class="paragraph">
+ <p>(As of DN 4.1) set a break point in <code>FetchRequest#execute(…)</code>:</p>
+ </div>
+ <div class="imageblock">
+ <div class="content">
+ <a class="image" href="images/hints-n-tips/diagnosing-n-plus-1.png"><img src="images/hints-n-tips/diagnosing-n-plus-1.png" alt="diagnosing n plus 1" width="800px"></a>
+ </div>
+ </div>
+ <div class="paragraph">
+ <p>The "Variables" pane will tell you which field(s) are being loaded, and the stack trace should help explain why the field is required.</p>
+ </div>
+ <div class="paragraph">
+ <p>For example, it may be that an object is being loaded in a table and the initial query did not eagerly load that field. In such a case, consider using fetch groups in the initial repository query to bring the required data into memory with just one SQL call. See <a href="ugodb.html#_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups">this hint/tip</a> for further details.</p>
+ </div>
+ </div>
+ <div class="sect2">
+ <h3 id="_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups">5.5. Typesafe Queries and Fetch-groups</h3>
+ <div class="btn-group" style="float: right; font-size: small; padding: 6px; margin-top: -55px; ">
+ <button type="button" class="btn btn-xs btn-default" onclick="window.location.href="https://github.com/apache/isis/edit/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups.adoc""><i class="fa fa-pencil-square-o"></i> Edit</button>
+ <button type="button" class="btn btn-xs btn-default dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"><span class="caret"></span><span class="sr-only">Toggle Dropdown</span></button>
+ <ul class="dropdown-menu">
+ <li><a href="https://github.com/apache/isis/edit/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups.adoc" target="_blank"><i class="fa fa-pencil-square-o fa-fw" aria-hidden="true"></i> Edit</a></li>
+ <li><a href="https://github.com/apache/isis/commits/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups.adoc" target="_blank"><i class="fa fa-clock-o fa-fw" aria-hidden="true"></i> History</a></li>
+ <li><a href="https://github.com/apache/isis/raw/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups.adoc" target="_blank"><i class="fa fa-file-text-o fa-fw" aria-hidden="true"></i> Raw</a></li>
+ <li><a href="https://github.com/apache/isis/blame/master/adocs/documentation/src/main/asciidoc/guides/ugodn/_ugodn_hints-and-tips_typesafe-queries-and-fetchgroups.adoc" target="_blank"><i class="fa fa-hand-o-right fa-fw" aria-hidden="true"></i> Blame</a></li>
+ </ul>
+ </div>
+ <div class="paragraph">
+ <p>Fetch groups provide a means to hint to DataNucleus that it should perform a SQL join when querying. A common use case is to avoid the <a href="#_ugodn_hints-and-tips_diagnosing-n-plus-1">n+1</a> issue.</p>
+ </div>
+ <div class="paragraph">
+ <p>(So far as I could ascertain) it isn’t possible to specify fetch group hints using JDOQL, but it is possible to specify them using the programmatic API or using typesafe queries.</p>
+ </div>
+ <div class="paragraph">
+ <p>For example, here’s a JDOQL query:</p>
+ </div>
+ <div class="listingblock">
+ <div class="content">
+ <pre class="CodeRay highlight"><code data-lang="java"><span class="annotation">@Query</span>(
+ name = <span class="string"><span class="delimiter">"</span><span class="content">findCompletedOrLaterWithItemsByReportedDate</span><span class="delimiter">"</span></span>, language = <span class="string"><span class="delimiter">"</span><span class="content">JDOQL</span><span class="delimiter">"</span></span>,
+ value = <span class="string"><span class="delimiter">"</span><span class="content">SELECT </span><span class="delimiter">"</span></span>
+ + <span class="string"><span class="delimiter">"</span><span class="content">FROM org.estatio.capex.dom.invoice.IncomingInvoice </span><span class="delimiter">"</span></span>
+ + <span class="string"><span class="delimiter">"</span><span class="content">WHERE items.contains(ii) </span><span class="delimiter">"</span></span>
+ + <span class="string"><span class="delimiter">"</span><span class="content"> && (ii.reportedDate == :reportedDate) </span><span class="delimiter">"</span></span>
+ + <span class="string"><span class="delimiter">"</span><span class="content"> && (approvalState != 'NEW' && approvalState != 'DISCARDED') </span><span class="delimiter">"</span></span>
+ + <span class="string"><span class="delimiter">"</span><span class="content">VARIABLES org.estatio.capex.dom.invoice.IncomingInvoiceItem ii </span><span class="delimiter">"</span></span>
+),
+<span class="directive">public</span> <span class="type">class</span> <span class="class">IncomingInvoice</span> ... { ... }</code></pre>
+ </div>
+ </div>
+ <div class="paragraph">
+ <p>which normally would be used from a repository:</p>
+ </div>
+ <div class="listingblock">
+ <div class="content">
+ <pre class="CodeRay highlight"><code data-lang="java"><span class="directive">public</span> <span class="predefined-type">List</span><IncomingInvoice> findCompletedOrLaterWithItemsByReportedDate(
+ <span class="directive">final</span> LocalDate reportedDate) {
+ <span class="keyword">return</span> repositoryService.allMatches(
+ <span class="keyword">new</span> QueryDefault<>(
+ IncomingInvoice.class,
+ <span class="string"><span class="delimiter">"</span><span class="content">findCompletedOrLaterWithItemsByReportedDate</span><span class="delimiter">"</span></span>,
+ <span class="string"><span class="delimiter">"</span><span class="content">reportedDate</span><span class="delimiter">"</span></span>, reportedDate));
+}</code></pre>
+ </div>
+ </div>
+ <div class="paragraph">
+ <p>This can be re-written as a type-safe query as follows:</p>
+ </div>
+ <div class="listingblock">
+ <div class="content">
+ <pre class="CodeRay highlight"><code data-lang="java"><span class="directive">public</span> <span class="predefined-type">List</span><IncomingInvoice> findCompletedOrLaterWithItemsByReportedDate(<span class="directive">final</span> LocalDate reportedDate) {
+
+ <span class="directive">final</span> QIncomingInvoice ii = QIncomingInvoice.candidate();
+ <span class="directive">final</span> QIncomingInvoiceItem iii = QIncomingInvoiceItem.variable(<span class="string"><span class="delimiter">"</span><span class="content">iii</span><span class="delimiter">"</span></span>);
+
+ <span class="directive">final</span> TypesafeQuery<IncomingInvoice> q =
+ isisJdoSupport.newTypesafeQuery(IncomingInvoice.class);
+
+ q.filter(
+ ii.items.contains(iii)
+ .and(iii.reportedDate.eq(reportedDate))
+ .and(ii.approvalState.ne(IncomingInvoiceApprovalState.NEW))
+ .and(ii.approvalState.ne(IncomingInvoiceApprovalState.DISCARDED)));
+ <span class="directive">final</span> <span class="predefined-type">List</span><IncomingInvoice> incomingInvoices = Lists.newArrayList(q.executeList());
+ q.closeAll();
+ <span class="keyword">return</span> incomingInvoices;
+}</code></pre>
+ </div>
+ </div>
+ <div class="paragraph">
+ <p>Now the <code>IncomingInvoice</code> has four fields that require eager loading. This can be specified by defining a named fetch group:</p>
+ </div>
+ <div class="listingblock">
+ <div class="content">
+ <pre class="CodeRay highlight"><code data-lang="java"><span class="annotation">@FetchGroup</span>(
+ name=<span class="string"><span class="delimiter">"</span><span class="content">seller_buyer_property_bankAccount</span><span class="delimiter">"</span></span>,
+ members={
+ <span class="annotation">@Persistent</span>(name=<span class="string"><span class="delimiter">"</span><span class="content">seller</span><span class="delimiter">"</span></span>),
+ <span class="annotation">@Persistent</span>(name=<span class="string"><span class="delimiter">"</span><span class="content">buyer</span><span class="delimiter">"</span></span>),
+ <span class="annotation">@Persistent</span>(name=<span class="string"><span class="delimiter">"</span><span class="content">property</span><span class="delimiter">"</span></span>),
+ <span class="annotation">@Persistent</span>(name=<span class="string"><span class="delimiter">"</span><span class="content">bankAccount</span><span class="delimiter">"</span></span>)
+ })
+<span class="directive">public</span> <span class="type">class</span> <span class="class">IncomingInvoice</span> ... { ... }</code></pre>
+ </div>
+ </div>
+ <div class="paragraph">
+ <p>This fetch group can then be used in the query using <code>q.getFetchPlan().addGroup(…)</code>. Putting this all together, we get:</p>
+ </div>
+ <div class="listingblock">
+ <div class="content">
+ <pre class="CodeRay highlight"><code data-lang="java"><span class="directive">public</span> <span class="predefined-type">List</span><IncomingInvoice> findCompletedOrLaterWithItemsByReportedDate(<span class="directive">final</span> LocalDate reportedDate) {
+
+ <span class="directive">final</span> QIncomingInvoice ii = QIncomingInvoice.candidate();
+ <span class="directive">final</span> QIncomingInvoiceItem iii = QIncomingInvoiceItem.variable(<span class="string"><span class="delimiter">"</span><span class="content">iii</span><span class="delimiter">"</span></span>);
+
+ <span class="directive">final</span> TypesafeQuery<IncomingInvoice> q =
+ isisJdoSupport.newTypesafeQuery(IncomingInvoice.class);
+
+ q.getFetchPlan().addGroup(<span class="string"><span class="delimiter">"</span><span class="content">seller_buyer_property_bankAccount</span><span class="delimiter">"</span></span>); <i class="conum" data-value="1"></i><b>(1)</b>
+
+ q.filter(
+ ii.items.contains(iii)
+ .and(iii.reportedDate.eq(reportedDate))
+ .and(ii.approvalState.ne(IncomingInvoiceApprovalState.NEW))
+ .and(ii.approvalState.ne(IncomingInvoiceApprovalState.DISCARDED)));
+ <span class="directive">final</span> <span class="predefined-type">List</span><IncomingInvoice> incomingInvoices = Lists.newArrayList(q.executeList());
+ q.closeAll();
+ <span class="keyword">return</span> incomingInvoices;
+}</code></pre>
+ </div>
+ </div>
+ <div class="colist arabic">
+ <table>
+ <tbody>
+ <tr>
+ <td><i class="conum" data-value="1"></i><b>1</b></td>
+ <td>specify the fetch group to use.</td>
+ </tr>
+ </tbody>
+ </table>
+ </div>
+ </div>
</div>
</div>
</div>