mirror of
https://github.com/GreptimeTeam/greptimedb.git
synced 2026-05-14 12:00:40 +00:00
26 lines
5.1 KiB
HTML
26 lines
5.1 KiB
HTML
<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Modifies a RecordBatch to include a sparse primary key column."><title>modify_batch_sparse in metric_engine::batch_modifier - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-17e0aaed.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="metric_engine" data-themes="" data-resource-suffix="" data-rustdoc-version="1.96.0-nightly (ac7f9ec7d 2026-03-20)" data-channel="nightly" data-search-js="search-63369b7b.js" data-stringdex-js="stringdex-2da4960a.js" data-settings-js="settings-170eb4bf.js" ><script src="../../static.files/storage-41dd4d93.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../static.files/main-5013f961.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-f7c3ffd8.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc fn"><a class="skip-main-content" href="#main-content">Skip to main content</a><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><rustdoc-topbar><h2><a href="#">modify_batch_sparse</a></h2></rustdoc-topbar><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../../metric_engine/index.html">metric_<wbr>engine</a><span class="version">1.0.0</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">modify_<wbr>batch_<wbr>sparse</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#parameters" title="Parameters">Parameters</a></li></ul></section><div id="rustdoc-modnav"><h2><a href="index.html">In metric_<wbr>engine::<wbr>batch_<wbr>modifier</a></h2></div></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><div class="width-limiter"><section id="main-content" class="content" tabindex="-1"><div class="main-heading"><div class="rustdoc-breadcrumbs"><a href="../index.html">metric_engine</a>::<wbr><a href="index.html">batch_modifier</a></div><h1>Function <span class="fn">modify_<wbr>batch_<wbr>sparse</span> <button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../../src/metric_engine/batch_modifier.rs.html#139-191">Source</a> </span></div><pre class="rust item-decl"><code>pub fn modify_batch_sparse(
|
||
batch: RecordBatch,
|
||
table_id: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a>,
|
||
sorted_tag_columns: &[<a class="struct" href="struct.TagColumnInfo.html" title="struct metric_engine::batch_modifier::TagColumnInfo">TagColumnInfo</a>],
|
||
extra_column_indices: &[<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>],
|
||
) -> <a class="type" href="../error/type.Result.html" title="type metric_engine::error::Result">Result</a><RecordBatch></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Modifies a [RecordBatch] to include a sparse primary key column.</p>
|
||
<p>This function transforms the input <code>batch</code> into a new <code>RecordBatch</code> where the first column
|
||
is the generated primary key (named [PRIMARY_KEY_COLUMN_NAME]), followed by columns
|
||
indicated by <code>extra_column_indices</code>.</p>
|
||
<p>The primary key uses a “sparse” encoding, which compactly represents the row’s identity
|
||
by only including non-null tag values. The encoding, handled by [SparsePrimaryKeyCodec],
|
||
consists of:</p>
|
||
<ol>
|
||
<li>The <code>table_id</code>.</li>
|
||
<li>A <code>tsid</code> (Time Series ID), which is a hash of the present tags.</li>
|
||
<li>The actual non-null tag values paired with their <code>column_id</code>.</li>
|
||
</ol>
|
||
<h2 id="parameters"><a class="doc-anchor" href="#parameters">§</a>Parameters</h2>
|
||
<ul>
|
||
<li><code>batch</code>: The source [RecordBatch].</li>
|
||
<li><code>table_id</code>: The ID of the table.</li>
|
||
<li><code>sorted_tag_columns</code>: Metadata for tag columns, used for both TSID computation and PK encoding.</li>
|
||
<li><code>extra_column_indices</code>: Indices of columns from the original batch to keep in the output
|
||
(typically the timestamp and value fields).</li>
|
||
</ul>
|
||
</div></details></section></div></main></body></html> |