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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:19:15 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:19:15 +0000 |
| commit | 6eb9c5a5657d1fe77b55cc261450f3538d35a94d (patch) | |
| tree | 657d8194422a5daccecfd42d654b8a245ef7b4c8 /doc/src/sgml/html/protocol-changes.html | |
| parent | Initial commit. (diff) | |
| download | postgresql-13-upstream.tar.xz postgresql-13-upstream.zip | |
Adding upstream version 13.4.upstream/13.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/protocol-changes.html')
| -rw-r--r-- | doc/src/sgml/html/protocol-changes.html | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/doc/src/sgml/html/protocol-changes.html b/doc/src/sgml/html/protocol-changes.html new file mode 100644 index 0000000..746491f --- /dev/null +++ b/doc/src/sgml/html/protocol-changes.html @@ -0,0 +1,73 @@ +<?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>52.10. Summary of Changes since Protocol 2.0</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="protocol-logicalrep-message-formats.html" title="52.9. Logical Replication Message Formats" /><link rel="next" href="source.html" title="Chapter 53. PostgreSQL Coding Conventions" /></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">52.10. Summary of Changes since Protocol 2.0</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="protocol-logicalrep-message-formats.html" title="52.9. Logical Replication Message Formats">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="protocol.html" title="Chapter 52. Frontend/Backend Protocol">Up</a></td><th width="60%" align="center">Chapter 52. Frontend/Backend Protocol</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 13.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="source.html" title="Chapter 53. PostgreSQL Coding Conventions">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="PROTOCOL-CHANGES"><div class="titlepage"><div><div><h2 class="title" style="clear: both">52.10. Summary of Changes since Protocol 2.0</h2></div></div></div><p> +This section provides a quick checklist of changes, for the benefit of +developers trying to update existing client libraries to protocol 3.0. +</p><p> +The initial startup packet uses a flexible list-of-strings format +instead of a fixed format. Notice that session default values for run-time +parameters can now be specified directly in the startup packet. (Actually, +you could do that before using the <code class="literal">options</code> field, but given the +limited width of <code class="literal">options</code> and the lack of any way to quote +whitespace in the values, it wasn't a very safe technique.) +</p><p> +All messages now have a length count immediately following the message type +byte (except for startup packets, which have no type byte). Also note that +PasswordMessage now has a type byte. +</p><p> +ErrorResponse and NoticeResponse ('<code class="literal">E</code>' and '<code class="literal">N</code>') +messages now contain multiple fields, from which the client code can +assemble an error message of the desired level of verbosity. Note that +individual fields will typically not end with a newline, whereas the single +string sent in the older protocol always did. +</p><p> +The ReadyForQuery ('<code class="literal">Z</code>') message includes a transaction status +indicator. +</p><p> +The distinction between BinaryRow and DataRow message types is gone; the +single DataRow message type serves for returning data in all formats. +Note that the layout of DataRow has changed to make it easier to parse. +Also, the representation of binary values has changed: it is no longer +directly tied to the server's internal representation. +</p><p> +There is a new <span class="quote">“<span class="quote">extended query</span>”</span> sub-protocol, which adds the frontend +message types Parse, Bind, Execute, Describe, Close, Flush, and Sync, and the +backend message types ParseComplete, BindComplete, PortalSuspended, +ParameterDescription, NoData, and CloseComplete. Existing clients do not +have to concern themselves with this sub-protocol, but making use of it +might allow improvements in performance or functionality. +</p><p> +<code class="command">COPY</code> data is now encapsulated into CopyData and CopyDone messages. There +is a well-defined way to recover from errors during <code class="command">COPY</code>. The special +<span class="quote">“<span class="quote"><code class="literal">\.</code></span>”</span> last line is not needed anymore, and is not sent +during <code class="command">COPY OUT</code>. +(It is still recognized as a terminator during <code class="command">COPY IN</code>, but its use is +deprecated and will eventually be removed.) Binary <code class="command">COPY</code> is supported. +The CopyInResponse and CopyOutResponse messages include fields indicating +the number of columns and the format of each column. +</p><p> +The layout of FunctionCall and FunctionCallResponse messages has changed. +FunctionCall can now support passing NULL arguments to functions. It also +can handle passing parameters and retrieving results in either text or +binary format. There is no longer any reason to consider FunctionCall a +potential security hole, since it does not offer direct access to internal +server data representations. +</p><p> +The backend sends ParameterStatus ('<code class="literal">S</code>') messages during connection +startup for all parameters it considers interesting to the client library. +Subsequently, a ParameterStatus message is sent whenever the active value +changes for any of these parameters. +</p><p> +The RowDescription ('<code class="literal">T</code>') message carries new table OID and column +number fields for each column of the described row. It also shows the format +code for each column. +</p><p> +The CursorResponse ('<code class="literal">P</code>') message is no longer generated by +the backend. +</p><p> +The NotificationResponse ('<code class="literal">A</code>') message has an additional string +field, which can carry a <span class="quote">“<span class="quote">payload</span>”</span> string passed +from the <code class="command">NOTIFY</code> event sender. +</p><p> +The EmptyQueryResponse ('<code class="literal">I</code>') message used to include an empty +string parameter; this has been removed. +</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="protocol-logicalrep-message-formats.html" title="52.9. Logical Replication Message Formats">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="protocol.html" title="Chapter 52. Frontend/Backend Protocol">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="source.html" title="Chapter 53. PostgreSQL Coding Conventions">Next</a></td></tr><tr><td width="40%" align="left" valign="top">52.9. Logical Replication Message Formats </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 13.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> Chapter 53. PostgreSQL Coding Conventions</td></tr></table></div></body></html>
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