<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Synchronous Replication Support for Logical Decoding</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 9.4.19 Documentation" HREF="index.html"><LINK REL="UP" TITLE="Logical Decoding" HREF="logicaldecoding.html"><LINK REL="PREVIOUS" TITLE="Logical Decoding Output Writers" HREF="logicaldecoding-writer.html"><LINK REL="NEXT" TITLE="Reference" HREF="reference.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2018-10-19T13:41:12"></HEAD ><BODY CLASS="SECT1" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="4" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.4.19 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="Logical Decoding Output Writers" HREF="logicaldecoding-writer.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="logicaldecoding.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 46. Logical Decoding</TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="Reference" HREF="reference.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="LOGICALDECODING-SYNCHRONOUS" >46.8. Synchronous Replication Support for Logical Decoding</A ></H1 ><P > Logical decoding can be used to to build <A HREF="warm-standby.html#SYNCHRONOUS-REPLICATION" >synchronous replication</A > solutions with the same user interface as synchronous replication for <A HREF="warm-standby.html#STREAMING-REPLICATION" >streaming replication</A >. To do this, the streaming replication interface (see <A HREF="logicaldecoding-walsender.html" >Section 46.3</A >) must be used to stream out data. Clients have to send <TT CLASS="LITERAL" >Standby status update (F)</TT > (see <A HREF="protocol-replication.html" >Section 49.3</A >) messages, just like streaming replication clients do. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > A synchronous replica receiving changes via logical decoding will work in the scope of a single database. Since, in contrast to that, <TT CLASS="PARAMETER" >synchronous_standby_names</TT > currently is server wide, this means this technique will not work properly if more than one database is actively used. </P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="logicaldecoding-writer.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="reference.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Logical Decoding Output Writers</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="logicaldecoding.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Reference</TD ></TR ></TABLE ></DIV ></BODY ></HTML >