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5th chunk of `doc/src/sgml/high-availability.sgml`
f94d892045153a628d9f4ff10a6157746ea19a0490ea64270000000100000fa0
 linkend="high-availability-matrix"/> summarizes
  the capabilities of the various solutions listed above.
 </para>

 <table id="high-availability-matrix">
  <title>High Availability, Load Balancing, and Replication Feature Matrix</title>
  <tgroup cols="9">
   <colspec colname="col1" colwidth="1.1*"/>
   <colspec colname="col2" colwidth="1*"/>
   <colspec colname="col3" colwidth="1*"/>
   <colspec colname="col4" colwidth="1*"/>
   <colspec colname="col5" colwidth="1*"/>
   <colspec colname="col6" colwidth="1*"/>
   <colspec colname="col7" colwidth="1*"/>
   <colspec colname="col8" colwidth="1*"/>
   <colspec colname="col9" colwidth="1*"/>
   <thead>
    <row>
     <entry>Feature</entry>
     <entry>Shared Disk</entry>
     <entry>File System Repl.</entry>
     <entry>Write-Ahead Log Shipping</entry>
     <entry>Logical Repl.</entry>
     <entry>Trigger-&zwsp;Based Repl.</entry>
     <entry>SQL Repl. Middle-ware</entry>
     <entry>Async. MM Repl.</entry>
     <entry>Sync. MM Repl.</entry>
    </row>
   </thead>

   <tbody>

    <row>
     <entry>Popular examples</entry>
     <entry align="center">NAS</entry>
     <entry align="center">DRBD</entry>
     <entry align="center">built-in streaming repl.</entry>
     <entry align="center">built-in logical repl., pglogical</entry>
     <entry align="center">Londiste, Slony</entry>
     <entry align="center">pgpool-II</entry>
     <entry align="center">Bucardo</entry>
     <entry align="center"></entry>
    </row>

    <row>
     <entry>Comm. method</entry>
     <entry align="center">shared disk</entry>
     <entry align="center">disk blocks</entry>
     <entry align="center">WAL</entry>
     <entry align="center">logical decoding</entry>
     <entry align="center">table rows</entry>
     <entry align="center">SQL</entry>
     <entry align="center">table rows</entry>
     <entry align="center">table rows and row locks</entry>
    </row>

    <row>
     <entry>No special hardware required</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
    </row>

    <row>
     <entry>Allows multiple primary servers</entry>
     <entry align="center"></entry>
     <entry align="center"></entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
    </row>

    <row>
     <entry>No overhead on primary</entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center"></entry>
    </row>

    <row>
     <entry>No waiting for multiple servers</entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center">with sync off</entry>
     <entry align="center">with sync off</entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
    </row>

    <row>
     <entry>Primary failure will never lose data</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">&bull;</entry>
     <entry align="center">with sync on</entry>
     <entry align="center">with sync on</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
     <entry align="center"></entry>
     <entry align="center">&bull;</entry>
    </row>

    <row>
     <entry>Replicas accept read-only queries</entry>
     <entry align="center"></entry>
Title: High Availability, Load Balancing, and Replication Feature Matrix
Summary
This table compares the features and capabilities of various high availability, load balancing, and replication solutions, including shared disk, file system replication, write-ahead log shipping, logical replication, trigger-based replication, SQL replication middleware, asynchronous and synchronous multimaster replication, highlighting their strengths and weaknesses.