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class="search-icon" tabindex="0"></span><input type="search" id="search_input_react" placeholder="Loading..." aria-label="Search" class="navbar__search-input search-bar" disabled=""></div></div></div></div><div role="presentation" class="navbar-sidebar__backdrop"></div></nav><div id="__docusaurus_skipToContent_fallback" class="main-wrapper mainWrapper_z2l0 docsWrapper_BCFX"><button aria-label="Scroll back to top" class="clean-btn theme-back-to-top-button backToTopButton_sjWU" type="button"></button><div class="docPage__5DB"><main class="docMainContainer_gTbr docMainContainerEnhanced_Uz_u"><div class="container padding-top--md padding-bottom--lg"><div class="row"><div class="col docItemCol_VOVn"><div class="docItemContainer_Djhp"><article><div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type="button" class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div class="theme-doc-markdown markdown"><header><h1>Approximate Histogram aggregators</h1></header><p>To use this Apache Druid extension, <a href="/docs/latest/configuration/extensions#loading-extensions">include</a> <code>druid-histogram</code> in the extensions load list.</p><p>The <code>druid-histogram</code> extension provides an approximate histogram aggregator and a fixed buckets histogram aggregator.</p><a name="approximate-histogram-aggregator"></a><h2 class="anchor anchorWithStickyNavbar_LWe7" id="approximate-histogram-aggregator-deprecated">Approximate Histogram aggregator (Deprecated)<a href="#approximate-histogram-aggregator-deprecated" class="hash-link" aria-label="Direct link to Approximate Histogram aggregator (Deprecated)" title="Direct link to Approximate Histogram aggregator (Deprecated)"></a></h2><div class="theme-admonition theme-admonition-info alert alert--info admonition_LlT9"><div class="admonitionHeading_tbUL"><span class="admonitionIcon_kALy"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>info</div><div class="admonitionContent_S0QG"><p> The Approximate Histogram aggregator is deprecated. Please use <a href="/docs/latest/development/extensions-core/datasketches-quantiles">DataSketches Quantiles</a> instead which provides a superior distribution-independent algorithm with formal error guarantees.</p></div></div><p>This aggregator is based on |
| <a href="http://jmlr.org/papers/volume11/ben-haim10a/ben-haim10a.pdf" target="_blank" rel="noopener noreferrer">http://jmlr.org/papers/volume11/ben-haim10a/ben-haim10a.pdf</a> |
| to compute approximate histograms, with the following modifications:</p><ul><li>some tradeoffs in accuracy were made in the interest of speed (see below)</li><li>the sketch maintains the exact original data as long as the number of |
| distinct data points is fewer than the resolutions (number of centroids), |
| increasing accuracy when there are few data points, or when dealing with |
| discrete data points. You can find some of the details in <a href="https://metamarkets.com/2013/histograms/" target="_blank" rel="noopener noreferrer">this post</a>.</li></ul><p>Here are a few things to note before using approximate histograms:</p><ul><li>As indicated in the original paper, there are no formal error bounds on the |
| approximation. In practice, the approximation gets worse if the distribution |
| is skewed.</li><li>The algorithm is order-dependent, so results can vary for the same query, due |
| to variations in the order in which results are merged.</li><li>In general, the algorithm only works well if the data that comes is randomly |
| distributed (i.e. if data points end up sorted in a column, approximation |
| will be horrible)</li><li>We traded accuracy for aggregation speed, taking some shortcuts when adding |
| histograms together, which can lead to pathological cases if your data is |
| ordered in some way, or if your distribution has long tails. It should be |
| cheaper to increase the resolution of the sketch to get the accuracy you need.</li></ul><p>That being said, those sketches can be useful to get a first order approximation |
| when averages are not good enough. Assuming most rows in your segment store |
| fewer data points than the resolution of histogram, you should be able to use |
| them for monitoring purposes and detect meaningful variations with a few |
| hundred centroids. To get good accuracy readings on 95th percentiles with |
| millions of rows of data, you may want to use several thousand centroids, |
| especially with long tails, since that's where the approximation will be worse.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="creating-approximate-histogram-sketches-at-ingestion-time">Creating approximate histogram sketches at ingestion time<a href="#creating-approximate-histogram-sketches-at-ingestion-time" class="hash-link" aria-label="Direct link to Creating approximate histogram sketches at ingestion time" title="Direct link to Creating approximate histogram sketches at ingestion time"></a></h3><p>To use this feature, an "approxHistogram" or "approxHistogramFold" aggregator must be included at |
| indexing time. The ingestion aggregator can only apply to numeric values. If you use "approxHistogram" |
| then any input rows missing the value will be considered to have a value of 0, while with "approxHistogramFold" |
| such rows will be ignored.</p><p>To query for results, an "approxHistogramFold" aggregator must be included in the |
| query.</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"approxHistogram or approxHistogramFold (at ingestion time), approxHistogramFold (at query time)"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <metric_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"resolution"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <integer></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"numBuckets"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <integer></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"lowerLimit"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <float></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"upperLimit"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <float></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><table><thead><tr><th>Property</th><th>Description</th><th>Default</th></tr></thead><tbody><tr><td><code>resolution</code></td><td>Number of centroids (data points) to store. The higher the resolution, the more accurate results are, but the slower the computation will be.</td><td>50</td></tr><tr><td><code>numBuckets</code></td><td>Number of output buckets for the resulting histogram. Bucket intervals are dynamic, based on the range of the underlying data. Use a post-aggregator to have finer control over the bucketing scheme</td><td>7</td></tr><tr><td><code>lowerLimit</code>/<code>upperLimit</code></td><td>Restrict the approximation to the given range. The values outside this range will be aggregated into two centroids. Counts of values outside this range are still maintained.</td><td>-INF/+INF</td></tr><tr><td><code>finalizeAsBase64Binary</code></td><td>If true, the finalized aggregator value will be a Base64-encoded byte array containing the serialized form of the histogram. If false, the finalized aggregator value will be a JSON representation of the histogram.</td><td>false</td></tr></tbody></table><h2 class="anchor anchorWithStickyNavbar_LWe7" id="fixed-buckets-histogram">Fixed Buckets Histogram<a href="#fixed-buckets-histogram" class="hash-link" aria-label="Direct link to Fixed Buckets Histogram" title="Direct link to Fixed Buckets Histogram"></a></h2><p>The fixed buckets histogram aggregator builds a histogram on a numeric column, with evenly-sized buckets across a specified value range. Values outside of the range are handled based on a user-specified outlier handling mode.</p><p>This histogram supports the min/max/quantiles post-aggregators but does not support the bucketing post-aggregators.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="when-to-use">When to use<a href="#when-to-use" class="hash-link" aria-label="Direct link to When to use" title="Direct link to When to use"></a></h3><p>The accuracy/usefulness of the fixed buckets histogram is extremely data-dependent; it is provided to support special use cases where the user has a great deal of prior information about the data being aggregated and knows that a fixed buckets implementation is suitable.</p><p>For general histogram and quantile use cases, the <a href="/docs/latest/development/extensions-core/datasketches-quantiles">DataSketches Quantiles Sketch</a> extension is recommended.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="properties">Properties<a href="#properties" class="hash-link" aria-label="Direct link to Properties" title="Direct link to Properties"></a></h3><table><thead><tr><th>Property</th><th>Description</th><th>Default</th></tr></thead><tbody><tr><td><code>type</code></td><td>Type of the aggregator. Must <code>fixedBucketsHistogram</code>.</td><td>No default, must be specified</td></tr><tr><td><code>name</code></td><td>Column name for the aggregator.</td><td>No default, must be specified</td></tr><tr><td><code>fieldName</code></td><td>Column name of the input to the aggregator.</td><td>No default, must be specified</td></tr><tr><td><code>lowerLimit</code></td><td>Lower limit of the histogram.</td><td>No default, must be specified</td></tr><tr><td><code>upperLimit</code></td><td>Upper limit of the histogram.</td><td>No default, must be specified</td></tr><tr><td><code>numBuckets</code></td><td>Number of buckets for the histogram. The range <!-- -->[lowerLimit, upperLimit]<!-- --> will be divided into <code>numBuckets</code> intervals of equal size.</td><td>10</td></tr><tr><td><code>outlierHandlingMode</code></td><td>Specifies how values outside of <!-- -->[lowerLimit, upperLimit]<!-- --> will be handled. Supported modes are "ignore", "overflow", and "clip". See <a href="#outlier-handling-modes">outlier handling modes</a> for more details.</td><td>No default, must be specified</td></tr><tr><td><code>finalizeAsBase64Binary</code></td><td>If true, the finalized aggregator value will be a Base64-encoded byte array containing the <a href="#serialization-formats">serialized form</a> of the histogram. If false, the finalized aggregator value will be a JSON representation of the histogram.</td><td>false</td></tr></tbody></table><p>An example aggregator spec is shown below:</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"fixedBucketsHistogram"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <metric_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"numBuckets"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <integer></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"lowerLimit"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <double></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"upperLimit"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <double></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"outlierHandlingMode"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <mode></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="outlier-handling-modes">Outlier handling modes<a href="#outlier-handling-modes" class="hash-link" aria-label="Direct link to Outlier handling modes" title="Direct link to Outlier handling modes"></a></h3><p>The outlier handling mode specifies what should be done with values outside of the histogram's range. There are three supported modes:</p><ul><li><code>ignore</code>: Throw away outlier values.</li><li><code>overflow</code>: A count of outlier values will be tracked by the histogram, available in the <code>lowerOutlierCount</code> and <code>upperOutlierCount</code> fields.</li><li><code>clip</code>: Outlier values will be clipped to the <code>lowerLimit</code> or the <code>upperLimit</code> and included in the histogram.</li></ul><p>If you don't care about outliers, <code>ignore</code> is the cheapest option performance-wise. There is currently no difference in storage size among the modes.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="output-fields">Output fields<a href="#output-fields" class="hash-link" aria-label="Direct link to Output fields" title="Direct link to Output fields"></a></h3><p>The histogram aggregator's output object has the following fields:</p><ul><li><code>lowerLimit</code>: Lower limit of the histogram</li><li><code>upperLimit</code>: Upper limit of the histogram</li><li><code>numBuckets</code>: Number of histogram buckets</li><li><code>outlierHandlingMode</code>: Outlier handling mode</li><li><code>count</code>: Total number of values contained in the histogram, excluding outliers</li><li><code>lowerOutlierCount</code>: Count of outlier values below <code>lowerLimit</code>. Only used if the outlier mode is <code>overflow</code>.</li><li><code>upperOutlierCount</code>: Count of outlier values above <code>upperLimit</code>. Only used if the outlier mode is <code>overflow</code>.</li><li><code>missingValueCount</code>: Count of null values seen by the histogram.</li><li><code>max</code>: Max value seen by the histogram. This does not include outlier values.</li><li><code>min</code>: Min value seen by the histogram. This does not include outlier values.</li><li><code>histogram</code>: An array of longs with size <code>numBuckets</code>, containing the bucket counts</li></ul><h3 class="anchor anchorWithStickyNavbar_LWe7" id="ingesting-existing-histograms">Ingesting existing histograms<a href="#ingesting-existing-histograms" class="hash-link" aria-label="Direct link to Ingesting existing histograms" title="Direct link to Ingesting existing histograms"></a></h3><p>It is also possible to ingest existing fixed buckets histograms. The input must be a Base64 string encoding a byte array that contains a serialized histogram object. Both "full" and "sparse" formats can be used. Please see <a href="#serialization-formats">Serialization formats</a> below for details.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="serialization-formats">Serialization formats<a href="#serialization-formats" class="hash-link" aria-label="Direct link to Serialization formats" title="Direct link to Serialization formats"></a></h3><h4 class="anchor anchorWithStickyNavbar_LWe7" id="full-serialization-format">Full serialization format<a href="#full-serialization-format" class="hash-link" aria-label="Direct link to Full serialization format" title="Direct link to Full serialization format"></a></h4><p>This format includes the full histogram bucket count array in the serialization format.</p><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token plain">byte: serialization version, must be 0x01</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">byte: encoding mode, 0x01 for full</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: lowerLimit</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: upperLimit</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">int: numBuckets</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">byte: outlier handling mode (0x00 for `ignore`, 0x01 for `overflow`, and 0x02 for `clip`)</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: count, total number of values contained in the histogram, excluding outliers</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: lowerOutlierCount</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: upperOutlierCount</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: missingValueCount</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: max</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: min</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">array of longs: bucket counts for the histogram</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h4 class="anchor anchorWithStickyNavbar_LWe7" id="sparse-serialization-format">Sparse serialization format<a href="#sparse-serialization-format" class="hash-link" aria-label="Direct link to Sparse serialization format" title="Direct link to Sparse serialization format"></a></h4><p>This format represents the histogram bucket counts as (bucketNum, count) pairs. This serialization format is used when less than half of the histogram's buckets have values.</p><div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token plain">byte: serialization version, must be 0x01</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">byte: encoding mode, 0x02 for sparse</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: lowerLimit</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: upperLimit</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">int: numBuckets</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">byte: outlier handling mode (0x00 for `ignore`, 0x01 for `overflow`, and 0x02 for `clip`)</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: count, total number of values contained in the histogram, excluding outliers</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: lowerOutlierCount</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: upperOutlierCount</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">long: missingValueCount</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: max</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">double: min</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">int: number of following (bucketNum, count) pairs</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">sequence of (int, long) pairs:</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> int: bucket number</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> count: bucket count</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="combining-histograms-with-different-bucketing-schemes">Combining histograms with different bucketing schemes<a href="#combining-histograms-with-different-bucketing-schemes" class="hash-link" aria-label="Direct link to Combining histograms with different bucketing schemes" title="Direct link to Combining histograms with different bucketing schemes"></a></h3><p>It is possible to combine two histograms with different bucketing schemes (lowerLimit, upperLimit, numBuckets) together.</p><p>The bucketing scheme of the "left hand" histogram will be preserved (i.e., when running a query, the bucketing schemes specified in the query's histogram aggregators will be preserved).</p><p>When merging, we assume that values are evenly distributed within the buckets of the "right hand" histogram.</p><p>When the right-hand histogram contains outliers (when using <code>overflow</code> mode), we assume that all of the outliers counted in the right-hand histogram will be outliers in the left-hand histogram as well.</p><p>For performance and accuracy reasons, we recommend avoiding aggregation of histograms with different bucketing schemes if possible.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="null-handling">Null handling<a href="#null-handling" class="hash-link" aria-label="Direct link to Null handling" title="Direct link to Null handling"></a></h3><p>If <code>druid.generic.useDefaultValueForNull</code> is false, null values will be tracked in the <code>missingValueCount</code> field of the histogram.</p><p>If <code>druid.generic.useDefaultValueForNull</code> is true, null values will be added to the histogram as the default 0.0 value.</p><h2 class="anchor anchorWithStickyNavbar_LWe7" id="histogram-post-aggregators">Histogram post-aggregators<a href="#histogram-post-aggregators" class="hash-link" aria-label="Direct link to Histogram post-aggregators" title="Direct link to Histogram post-aggregators"></a></h2><p>Post-aggregators are used to transform opaque approximate histogram sketches |
| into bucketed histogram representations, as well as to compute various |
| distribution metrics such as quantiles, min, and max.</p><h3 class="anchor anchorWithStickyNavbar_LWe7" id="equal-buckets-post-aggregator">Equal buckets post-aggregator<a href="#equal-buckets-post-aggregator" class="hash-link" aria-label="Direct link to Equal buckets post-aggregator" title="Direct link to Equal buckets post-aggregator"></a></h3><p>Computes a visual representation of the approximate histogram with a given number of equal-sized bins. |
| Bucket intervals are based on the range of the underlying data. This aggregator is not supported for the fixed buckets histogram.</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"type"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"equalBuckets"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"name"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"<output_name>"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"<aggregator_name>"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"numBuckets"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <count></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="buckets-post-aggregator">Buckets post-aggregator<a href="#buckets-post-aggregator" class="hash-link" aria-label="Direct link to Buckets post-aggregator" title="Direct link to Buckets post-aggregator"></a></h3><p>Computes a visual representation given an initial breakpoint, offset, and a bucket size.</p><p>Bucket size determines the width of the binning interval.</p><p>Offset determines the value on which those interval bins align.</p><p>This aggregator is not supported for the fixed buckets histogram.</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"type"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"buckets"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"name"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"<output_name>"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"<aggregator_name>"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"bucketSize"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <bucket_size></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"offset"</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <offset></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="custom-buckets-post-aggregator">Custom buckets post-aggregator<a href="#custom-buckets-post-aggregator" class="hash-link" aria-label="Direct link to Custom buckets post-aggregator" title="Direct link to Custom buckets post-aggregator"></a></h3><p>Computes a visual representation of the approximate histogram with bins laid out according to the given breaks.</p><p>This aggregator is not supported for the fixed buckets histogram.</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"customBuckets"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <aggregator_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"breaks"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">[</span><span class="token plain"> <value></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> <value></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> ... </span><span class="token punctuation" style="color:rgb(199, 146, 234)">]</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="min-post-aggregator">min post-aggregator<a href="#min-post-aggregator" class="hash-link" aria-label="Direct link to min post-aggregator" title="Direct link to min post-aggregator"></a></h3><p>Returns the minimum value of the underlying approximate or fixed buckets histogram aggregator</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"min"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <aggregator_name> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h3 class="anchor anchorWithStickyNavbar_LWe7" id="max-post-aggregator">max post-aggregator<a href="#max-post-aggregator" class="hash-link" aria-label="Direct link to max post-aggregator" title="Direct link to max post-aggregator"></a></h3><p>Returns the maximum value of the underlying approximate or fixed buckets histogram aggregator</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"max"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <aggregator_name> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h4 class="anchor anchorWithStickyNavbar_LWe7" id="quantile-post-aggregator">quantile post-aggregator<a href="#quantile-post-aggregator" class="hash-link" aria-label="Direct link to quantile post-aggregator" title="Direct link to quantile post-aggregator"></a></h4><p>Computes a single quantile based on the underlying approximate or fixed buckets histogram aggregator</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"quantile"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <aggregator_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"probability"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <quantile> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><h4 class="anchor anchorWithStickyNavbar_LWe7" id="quantiles-post-aggregator">quantiles post-aggregator<a href="#quantiles-post-aggregator" class="hash-link" aria-label="Direct link to quantiles post-aggregator" title="Direct link to quantiles post-aggregator"></a></h4><p>Computes an array of quantiles based on the underlying approximate or fixed buckets histogram aggregator</p><div class="language-json codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-json codeBlock_bY9V thin-scrollbar"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#bfc7d5"><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"> </span><span class="token property">"type"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">"quantiles"</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"name"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <output_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token property">"fieldName"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> <aggregator_name></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"> </span><span class="token property">"probabilities"</span><span class="token plain"> </span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">[</span><span class="token plain"> <quantile></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> <quantile></span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> ... </span><span class="token punctuation" style="color:rgb(199, 146, 234)">]</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div></div></article><nav class="pagination-nav docusaurus-mt-lg" aria-label="Docs pages"></nav></div></div><div class="col col--3"><div class="tableOfContents_bqdL thin-scrollbar theme-doc-toc-desktop"><ul class="table-of-contents table-of-contents__left-border"><li><a href="#approximate-histogram-aggregator-deprecated" class="table-of-contents__link toc-highlight">Approximate Histogram aggregator (Deprecated)</a><ul><li><a href="#creating-approximate-histogram-sketches-at-ingestion-time" class="table-of-contents__link toc-highlight">Creating approximate histogram sketches at ingestion time</a></li></ul></li><li><a href="#fixed-buckets-histogram" class="table-of-contents__link toc-highlight">Fixed Buckets Histogram</a><ul><li><a href="#when-to-use" class="table-of-contents__link toc-highlight">When to use</a></li><li><a href="#properties" class="table-of-contents__link toc-highlight">Properties</a></li><li><a href="#outlier-handling-modes" class="table-of-contents__link toc-highlight">Outlier handling modes</a></li><li><a href="#output-fields" class="table-of-contents__link toc-highlight">Output fields</a></li><li><a href="#ingesting-existing-histograms" class="table-of-contents__link toc-highlight">Ingesting existing histograms</a></li><li><a href="#serialization-formats" class="table-of-contents__link toc-highlight">Serialization formats</a></li><li><a href="#combining-histograms-with-different-bucketing-schemes" class="table-of-contents__link toc-highlight">Combining histograms with different bucketing schemes</a></li><li><a href="#null-handling" class="table-of-contents__link toc-highlight">Null handling</a></li></ul></li><li><a href="#histogram-post-aggregators" class="table-of-contents__link toc-highlight">Histogram post-aggregators</a><ul><li><a href="#equal-buckets-post-aggregator" class="table-of-contents__link toc-highlight">Equal buckets post-aggregator</a></li><li><a href="#buckets-post-aggregator" class="table-of-contents__link toc-highlight">Buckets post-aggregator</a></li><li><a href="#custom-buckets-post-aggregator" class="table-of-contents__link toc-highlight">Custom buckets post-aggregator</a></li><li><a href="#min-post-aggregator" class="table-of-contents__link toc-highlight">min post-aggregator</a></li><li><a href="#max-post-aggregator" class="table-of-contents__link toc-highlight">max post-aggregator</a></li></ul></li></ul></div></div></div></div></main></div></div><footer class="footer"><div class="container container-fluid"><div class="footer__bottom text--center"><div class="margin-bottom--sm"><img src="/img/favicon.png" class="themedImage_ToTc themedImage--light_HNdA footer__logo"><img src="/img/favicon.png" class="themedImage_ToTc themedImage--dark_i4oU footer__logo"></div><div class="footer__copyright">Copyright © 2023 Apache Software Foundation. Except where otherwise noted, licensed under CC BY-SA 4.0. Apache Druid, Druid, and the Druid logo are either registered trademarks or trademarks of The Apache Software Foundation in the United States and other countries.</div></div></div></footer></div> |
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