docs: Add acronym and glossary entries for I/O and AIO

These are fairly basic, but better than nothing.  While there are several
opportunities to link to these entries, this patch does not add any. They will
however be referenced by future patches.

Reviewed-by: Noah Misch <[email protected]>
Discussion: https://postgr.es/m/[email protected]

2 files changed, 57 insertions, 0 deletions

diff --git a/doc/src/sgml/acronyms.sgml b/doc/src/sgml/acronyms.sgml
index 58d0d90fece..2f906e9f018 100644
--- a/doc/src/sgml/acronyms.sgml
+++ b/doc/src/sgml/acronyms.sgml
@@ -10,6 +10,15 @@
   <variablelist>
 
    <varlistentry>
+    <term><acronym>AIO</acronym></term>
+    <listitem>
+     <para>
+      <link linkend="glossary-aio">Asynchronous <acronym>I/O</acronym></link>
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><acronym>ACL</acronym></term>
     <listitem>
      <para>
@@ -355,6 +364,15 @@
    </varlistentry>
 
    <varlistentry>
+    <term><acronym>I/O</acronym></term>
+    <listitem>
+     <para>
+      <link linkend="glossary-io">Input/Output</link>
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><acronym>ISO</acronym></term>
     <listitem>
      <para>
diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index c0f812e3f5e..b88cac598e9 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -81,6 +81,31 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-aio">
+   <glossterm>Asynchronous <acronym>I/O</acronym></glossterm>
+   <acronym>AIO</acronym>
+   <indexterm>
+    <primary>Asynchronous <acronym>I/O</acronym></primary>
+   </indexterm>
+   <glossdef>
+    <para>
+     Asynchronous <acronym>I/O</acronym> (<acronym>AIO</acronym>) describes
+     performing <acronym>I/O</acronym> in a non-blocking way (asynchronously),
+     in contrast to synchronous <acronym>I/O</acronym>, which blocks for the
+     entire duration of the <acronym>I/O</acronym>.
+    </para>
+    <para>
+     With <acronym>AIO</acronym>, starting an <acronym>I/O</acronym> operation
+     is separated from waiting for the result of the operation, allowing
+     multiple <acronym>I/O</acronym> operations to be initiated concurrently,
+     as well as performing <acronym>CPU</acronym> heavy operations
+     concurrently with <acronym>I/O</acronym>. The price for that increased
+     concurrency is increased complexity.
+    </para>
+    <glossseealso otherterm="glossary-io" />
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-atomic">
    <glossterm>Atomic</glossterm>
    <glossdef>
@@ -938,6 +963,20 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-io">
+   <glossterm>Input/Output</glossterm>
+   <acronym>I/O</acronym>
+   <glossdef>
+    <para>
+     Input/Output (<acronym>I/O</acronym>) describes the communication between
+     a program and peripheral devices. In the context of database systems,
+     <acronym>I/O</acronym> commonly, but not exclusively, refers to
+     interaction with storage devices or the network.
+    </para>
+    <glossseealso otherterm="glossary-aio" />
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-insert">
    <glossterm>Insert</glossterm>
    <glossdef>