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+<!--
+doc/src/sgml/ref/drop_index.sgml
+PostgreSQL documentation
+-->
+
+<refentry id="sql-dropindex">
+ <indexterm zone="sql-dropindex">
+  <primary>DROP INDEX</primary>
+ </indexterm>
+
+ <refmeta>
+  <refentrytitle>DROP INDEX</refentrytitle>
+  <manvolnum>7</manvolnum>
+  <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+  <refname>DROP INDEX</refname>
+  <refpurpose>remove an index</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] <replaceable class="parameter">name</replaceable> [, ...] [ CASCADE | RESTRICT ]
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+
+  <para>
+   <command>DROP INDEX</command> drops an existing index from the database
+   system. To execute this command you must be the owner of
+   the index.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Parameters</title>
+
+  <variablelist>
+   <varlistentry>
+    <term><literal>CONCURRENTLY</literal></term>
+    <listitem>
+     <para>
+      Drop the index without locking out concurrent selects, inserts, updates,
+      and deletes on the index's table.  A normal <command>DROP INDEX</command>
+      acquires an <literal>ACCESS EXCLUSIVE</literal> lock on the table,
+      blocking other accesses until the index drop can be completed.  With
+      this option, the command instead waits until conflicting transactions
+      have completed.
+     </para>
+     <para>
+      There are several caveats to be aware of when using this option.
+      Only one index name can be specified, and the <literal>CASCADE</literal> option
+      is not supported.  (Thus, an index that supports a <literal>UNIQUE</literal> or
+      <literal>PRIMARY KEY</literal> constraint cannot be dropped this way.)
+      Also, regular <command>DROP INDEX</command> commands can be
+      performed within a transaction block, but
+      <command>DROP INDEX CONCURRENTLY</command> cannot.
+      Lastly, indexes on partitioned tables cannot be dropped using this
+      option.
+     </para>
+     <para>
+      For temporary tables, <command>DROP INDEX</command> is always
+      non-concurrent, as no other session can access them, and
+      non-concurrent index drop is cheaper.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>IF EXISTS</literal></term>
+    <listitem>
+     <para>
+      Do not throw an error if the index does not exist. A notice is issued
+      in this case.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><replaceable class="parameter">name</replaceable></term>
+    <listitem>
+     <para>
+      The name (optionally schema-qualified) of an index to remove.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>CASCADE</literal></term>
+    <listitem>
+     <para>
+      Automatically drop objects that depend on the index,
+      and in turn all objects that depend on those objects
+      (see <xref linkend="ddl-depend"/>).
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>RESTRICT</literal></term>
+    <listitem>
+     <para>
+      Refuse to drop the index if any objects depend on it.  This is
+      the default.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </refsect1>
+
+ <refsect1>
+  <title>Examples</title>
+
+  <para>
+   This command will remove the index <literal>title_idx</literal>:
+
+<programlisting>
+DROP INDEX title_idx;
+</programlisting></para>
+ </refsect1>
+
+ <refsect1>
+  <title>Compatibility</title>
+
+  <para>
+   <command>DROP INDEX</command> is a
+   <productname>PostgreSQL</productname> language extension.  There
+   are no provisions for indexes in the SQL standard.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>See Also</title>
+
+  <simplelist type="inline">
+   <member><xref linkend="sql-createindex"/></member>
+  </simplelist>
+ </refsect1>
+
+</refentry>