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diff --git a/doc/src/sgml/html/logical-replication-conflicts.html b/doc/src/sgml/html/logical-replication-conflicts.html new file mode 100644 index 0000000..deb472b --- /dev/null +++ b/doc/src/sgml/html/logical-replication-conflicts.html @@ -0,0 +1,66 @@ +<?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>31.5. Conflicts</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 Vsnapshot" /><link rel="prev" href="logical-replication-col-lists.html" title="31.4. Column Lists" /><link rel="next" href="logical-replication-restrictions.html" title="31.6. Restrictions" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">31.5. Conflicts</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="logical-replication-col-lists.html" title="31.4. Column Lists">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="logical-replication.html" title="Chapter 31. Logical Replication">Up</a></td><th width="60%" align="center">Chapter 31. Logical Replication</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="logical-replication-restrictions.html" title="31.6. Restrictions">Next</a></td></tr></table><hr /></div><div class="sect1" id="LOGICAL-REPLICATION-CONFLICTS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">31.5. Conflicts <a href="#LOGICAL-REPLICATION-CONFLICTS" class="id_link">#</a></h2></div></div></div><p> + Logical replication behaves similarly to normal DML operations in that + the data will be updated even if it was changed locally on the subscriber + node. If incoming data violates any constraints the replication will + stop. This is referred to as a <em class="firstterm">conflict</em>. When + replicating <code class="command">UPDATE</code> or <code class="command">DELETE</code> + operations, missing data will not produce a conflict and such operations + will simply be skipped. + </p><p> + Logical replication operations are performed with the privileges of the role + which owns the subscription. Permissions failures on target tables will + cause replication conflicts, as will enabled + <a class="link" href="ddl-rowsecurity.html" title="5.8. Row Security Policies">row-level security</a> on target tables + that the subscription owner is subject to, without regard to whether any + policy would ordinarily reject the <code class="command">INSERT</code>, + <code class="command">UPDATE</code>, <code class="command">DELETE</code> or + <code class="command">TRUNCATE</code> which is being replicated. This restriction on + row-level security may be lifted in a future version of + <span class="productname">PostgreSQL</span>. + </p><p> + A conflict will produce an error and will stop the replication; it must be + resolved manually by the user. Details about the conflict can be found in + the subscriber's server log. + </p><p> + The resolution can be done either by changing data or permissions on the subscriber so + that it does not conflict with the incoming change or by skipping the + transaction that conflicts with the existing data. When a conflict produces + an error, the replication won't proceed, and the logical replication worker will + emit the following kind of message to the subscriber's server log: +</p><pre class="screen"> +ERROR: duplicate key value violates unique constraint "test_pkey" +DETAIL: Key (c)=(1) already exists. +CONTEXT: processing remote data for replication origin "pg_16395" during "INSERT" for replication target relation "public.test" in transaction 725 finished at 0/14C0378 +</pre><p> + The LSN of the transaction that contains the change violating the constraint and + the replication origin name can be found from the server log (LSN 0/14C0378 and + replication origin <code class="literal">pg_16395</code> in the above case). The + transaction that produced the conflict can be skipped by using + <code class="command">ALTER SUBSCRIPTION ... SKIP</code> with the finish LSN + (i.e., LSN 0/14C0378). The finish LSN could be an LSN at which the transaction + is committed or prepared on the publisher. Alternatively, the transaction can + also be skipped by calling the <a class="link" href="functions-admin.html#PG-REPLICATION-ORIGIN-ADVANCE"> + <code class="function">pg_replication_origin_advance()</code></a> function. + Before using this function, the subscription needs to be disabled temporarily + either by <code class="command">ALTER SUBSCRIPTION ... DISABLE</code> or, the + subscription can be used with the + <a class="link" href="sql-createsubscription.html#SQL-CREATESUBSCRIPTION-WITH-DISABLE-ON-ERROR"><code class="literal">disable_on_error</code></a> + option. Then, you can use <code class="function">pg_replication_origin_advance()</code> + function with the <em class="parameter"><code>node_name</code></em> (i.e., <code class="literal">pg_16395</code>) + and the next LSN of the finish LSN (i.e., 0/14C0379). The current position of + origins can be seen in the <a class="link" href="view-pg-replication-origin-status.html" title="54.18. pg_replication_origin_status"> + <code class="structname">pg_replication_origin_status</code></a> system view. + Please note that skipping the whole transaction includes skipping changes that + might not violate any constraint. This can easily make the subscriber + inconsistent. + </p><p> + When the + <a class="link" href="sql-createsubscription.html#SQL-CREATESUBSCRIPTION-WITH-STREAMING"><code class="literal">streaming</code></a> + mode is <code class="literal">parallel</code>, the finish LSN of failed transactions + may not be logged. In that case, it may be necessary to change the streaming + mode to <code class="literal">on</code> or <code class="literal">off</code> and cause the same + conflicts again so the finish LSN of the failed transaction will be written + to the server log. For the usage of finish LSN, please refer to <a class="link" href="sql-altersubscription.html" title="ALTER SUBSCRIPTION"><code class="command">ALTER SUBSCRIPTION ... + SKIP</code></a>. + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="logical-replication-col-lists.html" title="31.4. Column Lists">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="logical-replication.html" title="Chapter 31. Logical Replication">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="logical-replication-restrictions.html" title="31.6. Restrictions">Next</a></td></tr><tr><td width="40%" align="left" valign="top">31.4. Column Lists </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 31.6. Restrictions</td></tr></table></div></body></html>
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