greptimedb/servers/semantic/index.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="Per-table semantic metadata accumulated during one ingest pass (OTLP metrics, Prometheus remote write v2)."><title>servers::semantic - 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-1ed95124.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="servers" data-themes="" data-resource-suffix="" data-rustdoc-version="1.98.1 (48a229cea 2026-09-01)" data-channel="1.98.1" data-search-js="search-9944d736.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-417ebf0a.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 mod"><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="#">Module semantic</a></h2></rustdoc-topbar><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../../servers/index.html">servers</a><span class="version">1.4.0-alpha.0</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">Module semantic</a></h2><h3><a href="#structs">Module Items</a></h3><ul class="block"><li><a href="#structs" title="Structs">Structs</a></li><li><a href="#constants" title="Constants">Constants</a></li><li><a href="#functions" title="Functions">Functions</a></li></ul></section><div id="rustdoc-modnav"><h2 class="in-crate"><a href="../index.html">In crate servers</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">servers</a></div><h1>Module <span>semantic</span>&nbsp;<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/servers/semantic.rs.html#15-325">Source</a> </span></div><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Per-table semantic metadata accumulated during one ingest pass (OTLP
metrics, Prometheus remote write v2).</p>
<p>Each written table collects the scalar semantic keys its wire metadata
declares (an OTLP histogram fans out into <code>_bucket</code>/<code>_sum</code>/<code>_count</code>
companions; a remote write series names one metric family). The resulting
index is serialized onto the <code>greptime.internal.semantic.per_table_index</code>
context extension as <code>{schema -&gt; {table -&gt; {key -&gt; value}}}</code> and folded into
each table’s options at auto-create time.</p>
<p>Conflict handling follows the RFC: when two sources disagree on a
single-valued key the value collapses to <code>mixed</code> (or <code>unknown</code> for keys whose
domain has no <code>mixed</code>).</p>
</div></details><h2 id="structs" class="section-header">Structs<a href="#structs" class="anchor">§</a></h2><dl class="item-table"><dt><a class="struct" href="struct.SemanticIndex.html" title="struct servers::semantic::SemanticIndex">Semantic<wbr>Index</a></dt><dd>Index of <code>{table_name -&gt; {semantic_key -&gt; value}}</code> for one target schema.</dd><dt><a class="struct" href="struct.SemanticIndexes.html" title="struct servers::semantic::SemanticIndexes">Semantic<wbr>Indexes</a></dt><dd>Schema-aware collection of <a href="struct.SemanticIndex.html" title="struct servers::semantic::SemanticIndex"><code>SemanticIndex</code></a>es: Prometheus remote write lets
each series override the target schema with a special label, so one request
may write the same metric name into several schemas — their metadata must
not collapse into each other.</dd></dl><h2 id="constants" class="section-header">Constants<a href="#constants" class="anchor">§</a></h2><dl class="item-table"><dt><a class="constant" href="constant.METRIC_TYPE_COUNTER.html" title="constant servers::semantic::METRIC_TYPE_COUNTER">METRIC_<wbr>TYPE_<wbr>COUNTER</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_GAUGE.html" title="constant servers::semantic::METRIC_TYPE_GAUGE">METRIC_<wbr>TYPE_<wbr>GAUGE</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_GAUGE_HISTOGRAM.html" title="constant servers::semantic::METRIC_TYPE_GAUGE_HISTOGRAM">METRIC_<wbr>TYPE_<wbr>GAUGE_<wbr>HISTOGRAM</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_HISTOGRAM.html" title="constant servers::semantic::METRIC_TYPE_HISTOGRAM">METRIC_<wbr>TYPE_<wbr>HISTOGRAM</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_INFO.html" title="constant servers::semantic::METRIC_TYPE_INFO">METRIC_<wbr>TYPE_<wbr>INFO</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_STATESET.html" title="constant servers::semantic::METRIC_TYPE_STATESET">METRIC_<wbr>TYPE_<wbr>STATESET</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_SUMMARY.html" title="constant servers::semantic::METRIC_TYPE_SUMMARY">METRIC_<wbr>TYPE_<wbr>SUMMARY</a></dt><dt><a class="constant" href="constant.METRIC_TYPE_UPDOWN_COUNTER.html" title="constant servers::semantic::METRIC_TYPE_UPDOWN_COUNTER">METRIC_<wbr>TYPE_<wbr>UPDOWN_<wbr>COUNTER</a></dt></dl><h2 id="functions" class="section-header">Functions<a href="#functions" class="anchor">§</a></h2><dl class="item-table"><dt><a class="fn" href="fn.collapse_value.html" title="fn servers::semantic::collapse_value">collapse_<wbr>value</a><span title="Restricted Visibility">&nbsp;🔒</span> </dt><dd>The collapsed value for a conflicting scalar key: <code>mixed</code> when the key’s
domain accepts it, else <code>unknown</code>. Uses the vocabulary validator as the
single source of truth for which keys allow <code>mixed</code>.</dd><dt><a class="fn" href="fn.openmetrics_unit_to_ucum.html" title="fn servers::semantic::openmetrics_unit_to_ucum">openmetrics_<wbr>unit_<wbr>to_<wbr>ucum</a></dt><dd>Maps an OpenMetrics unit name (open vocabulary full words: <code>seconds</code>,
<code>bytes</code>) to the UCUM code the <code>greptime.semantic.metric.unit</code> option is
defined in. Only the OpenMetrics base units are mapped; anything else is
dropped — a missing unit beats a corrupted cross-protocol vocabulary.</dd></dl></section></div></main></body></html>