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//proc/thread-self/root/opt/postgresql-13/doc/html/view-pg-shmem-allocations.html
<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>51.87. pg_shmem_allocations</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="view-pg-shadow.html" title="51.86. pg_shadow" /><link rel="next" href="view-pg-stats.html" title="51.88. pg_stats" /></head><body id="docContent" class="container-fluid col-10"><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">51.87. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_shmem_allocations</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="view-pg-shadow.html" title="51.86. pg_shadow">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 51. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 51. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 13.1 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="view-pg-stats.html" title="51.88. pg_stats">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="VIEW-PG-SHMEM-ALLOCATIONS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">51.87. <code class="structname">pg_shmem_allocations</code></h2></div></div></div><a id="id-1.10.4.89.2" class="indexterm"></a><p> The <code class="structname">pg_shmem_allocations</code> view shows allocations made from the server's main shared memory segment. This includes both memory allocated by <span class="productname">postgres</span> itself and memory allocated by extensions using the mechanisms detailed in <a class="xref" href="xfunc-c.html#XFUNC-SHARED-ADDIN" title="37.10.10. Shared Memory and LWLocks">Section 37.10.10</a>. </p><p> Note that this view does not include memory allocated using the dynamic shared memory infrastructure. </p><div class="table" id="id-1.10.4.89.5"><p class="title"><strong>Table 51.88. <code class="structname">pg_shmem_allocations</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_shmem_allocations Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition"> Column Type </p> <p> Description </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition"> <code class="structfield">name</code> <code class="type">text</code> </p> <p> The name of the shared memory allocation. NULL for unused memory and <code class="literal"><anonymous></code> for anonymous allocations. </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> <code class="structfield">off</code> <code class="type">int8</code> </p> <p> The offset at which the allocation starts. NULL for anonymous allocations and unused memory. </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> <code class="structfield">size</code> <code class="type">int8</code> </p> <p> Size of the allocation </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> <code class="structfield">allocated_size</code> <code class="type">int8</code> </p> <p> Size of the allocation including padding. For anonymous allocations, no information about padding is available, so the <code class="literal">size</code> and <code class="literal">allocated_size</code> columns will always be equal. Padding is not meaningful for free memory, so the columns will be equal in that case also. </p></td></tr></tbody></table></div></div><br class="table-break" /><p> Anonymous allocations are allocations that have been made with <code class="literal">ShmemAlloc()</code> directly, rather than via <code class="literal">ShmemInitStruct()</code> or <code class="literal">ShmemInitHash()</code>. </p><p> By default, the <code class="structname">pg_shmem_allocations</code> view can be read only by superusers. </p></div><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navfooter"><hr></hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="view-pg-shadow.html" title="51.86. pg_shadow">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 51. 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