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<div class="sub-title"><span class="package-label-in-type">Package</span>&nbsp;<a href="package-summary.html">org.apache.calcite.plan</a></div>
<h1 title="Class RelOptSamplingParameters" class="title">Class RelOptSamplingParameters</h1>
</div>
<div class="inheritance" title="Inheritance Tree"><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">java.lang.Object</a>
<div class="inheritance">org.apache.calcite.plan.RelOptSamplingParameters</div>
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<div class="type-signature"><span class="modifiers">public class </span><span class="element-name type-name-label">RelOptSamplingParameters</span>
<span class="extends-implements">extends <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Object.html" title="class or interface in java.lang" class="external-link">Object</a></span></div>
<div class="block">RelOptSamplingParameters represents the parameters necessary to produce a
sample of a relation.
<p>It's parameters are derived from the SQL 2003 TABLESAMPLE clause.</div>
</section>
<section class="summary">
<ul class="summary-list">
<!-- ======== CONSTRUCTOR SUMMARY ======== -->
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<section class="constructor-summary" id="constructor-summary">
<h2>Constructor Summary</h2>
<div class="caption"><span>Constructors</span></div>
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<div class="table-header col-first">Constructor</div>
<div class="table-header col-last">Description</div>
<div class="col-constructor-name even-row-color"><code><a href="#%3Cinit%3E(boolean,float,boolean,int)" class="member-name-link">RelOptSamplingParameters</a><wbr>(boolean&nbsp;isBernoulli,
float&nbsp;samplingPercentage,
boolean&nbsp;isRepeatable,
int&nbsp;repeatableSeed)</code></div>
<div class="col-last even-row-color">&nbsp;</div>
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<h2>Method Summary</h2>
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<div class="table-header col-second">Method</div>
<div class="table-header col-last">Description</div>
<div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>int</code></div>
<div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getRepeatableSeed()" class="member-name-link">getRepeatableSeed</a>()</code></div>
<div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">If <a href="#isRepeatable()"><code>isRepeatable()</code></a> returns <code>true</code>, this method returns a
user-specified seed value.</div>
</div>
<div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>float</code></div>
<div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#getSamplingPercentage()" class="member-name-link">getSamplingPercentage</a>()</code></div>
<div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">Returns the sampling percentage.</div>
</div>
<div class="col-first even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>boolean</code></div>
<div class="col-second even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#isBernoulli()" class="member-name-link">isBernoulli</a>()</code></div>
<div class="col-last even-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">Indicates whether Bernoulli or system sampling should be performed.</div>
</div>
<div class="col-first odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code>boolean</code></div>
<div class="col-second odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4"><code><a href="#isRepeatable()" class="member-name-link">isRepeatable</a>()</code></div>
<div class="col-last odd-row-color method-summary-table method-summary-table-tab2 method-summary-table-tab4">
<div class="block">Indicates whether the sample results should be repeatable.</div>
</div>
</div>
</div>
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</section>
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<section class="constructor-details" id="constructor-detail">
<h2>Constructor Details</h2>
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<li>
<section class="detail" id="&lt;init&gt;(boolean,float,boolean,int)">
<h3>RelOptSamplingParameters</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="element-name">RelOptSamplingParameters</span><wbr><span class="parameters">(boolean&nbsp;isBernoulli,
float&nbsp;samplingPercentage,
boolean&nbsp;isRepeatable,
int&nbsp;repeatableSeed)</span></div>
</section>
</li>
</ul>
</section>
</li>
<!-- ============ METHOD DETAIL ========== -->
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<h2>Method Details</h2>
<ul class="member-list">
<li>
<section class="detail" id="isBernoulli()">
<h3>isBernoulli</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type">boolean</span>&nbsp;<span class="element-name">isBernoulli</span>()</div>
<div class="block">Indicates whether Bernoulli or system sampling should be performed.
Bernoulli sampling requires the decision whether to include each row in
the sample to be independent across rows. System sampling allows
implementation-dependent behavior.</div>
<dl class="notes">
<dt>Returns:</dt>
<dd>true if Bernoulli sampling is configured, false for system
sampling</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="getSamplingPercentage()">
<h3>getSamplingPercentage</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type">float</span>&nbsp;<span class="element-name">getSamplingPercentage</span>()</div>
<div class="block">Returns the sampling percentage. For Bernoulli sampling, the sampling
percentage is the likelihood that any given row will be included in the
sample. For system sampling, the sampling percentage indicates (roughly)
what percentage of the rows will appear in the sample.</div>
<dl class="notes">
<dt>Returns:</dt>
<dd>the sampling percentage between 0.0 and 1.0, exclusive</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="isRepeatable()">
<h3>isRepeatable</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type">boolean</span>&nbsp;<span class="element-name">isRepeatable</span>()</div>
<div class="block">Indicates whether the sample results should be repeatable. Sample results
are only required to repeat if no changes have been made to the
relation's content or structure. If the sample is configured to be
repeatable, then a user-specified seed value can be obtained via
<a href="#getRepeatableSeed()"><code>getRepeatableSeed()</code></a>.</div>
<dl class="notes">
<dt>Returns:</dt>
<dd>true if the sample results should be repeatable</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="getRepeatableSeed()">
<h3>getRepeatableSeed</h3>
<div class="member-signature"><span class="modifiers">public</span>&nbsp;<span class="return-type">int</span>&nbsp;<span class="element-name">getRepeatableSeed</span>()</div>
<div class="block">If <a href="#isRepeatable()"><code>isRepeatable()</code></a> returns <code>true</code>, this method returns a
user-specified seed value. Samples of the same, unmodified relation
should be identical if the sampling mode, sampling percentage and
repeatable seed are the same.</div>
<dl class="notes">
<dt>Returns:</dt>
<dd>seed value for repeatable samples</dd>
</dl>
</section>
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