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* [PATCH v4] doc: Mention that JIT inlining does not work with Meson builds
@ 2026-09-18 02:09 Yugo Nagata <nagata@sraoss.co.jp>
0 siblings, 0 replies; 1+ messages in thread
From: Yugo Nagata @ 2026-09-18 02:09 UTC (permalink / raw)
Meson builds do not generate the LLVM bitcode that JIT inlining
needs. So with -Dllvm, JIT compilation works, but inlining does
not. Document that in the JIT chapter, and mention -Dllvm next to
--with-llvm.
While at it, use <option> for --with-llvm, per review.
This should be reverted once Meson learns to build the bitcode.
Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: shihao zhong <zhong950419@gmail.com>
Discussion: https://postgr.es/m/20250526150820.28ea70625645e0d6d12be7d5@sraoss.co.jp
Backpatch-through: 16
---
doc/src/sgml/jit.sgml | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
inline patch 1: doc/src/sgml/jit.sgml (+13/-2 lines) download inline-1.patch
diff --git a/doc/src/sgml/jit.sgml b/doc/src/sgml/jit.sgml
index 44e18bf1a6f..fb934ce6fac 100644
--- a/doc/src/sgml/jit.sgml
+++ b/doc/src/sgml/jit.sgml
@@ -36,7 +36,8 @@
<acronym>JIT</acronym> compilation using <ulink
url="https://llvm.org/"><productname>LLVM</productname></ulink; when
<productname>PostgreSQL</productname> is built with
- <link linkend="configure-with-llvm"><literal>--with-llvm</literal></link>.
+ <link linkend="configure-with-llvm"><option>--with-llvm</option></link>
+ or <link linkend="configure-with-llvm-meson"><option>-Dllvm</option></link>.
</para>
<para>
@@ -76,6 +77,16 @@
bodies of small functions into the expressions using them. That allows a
significant percentage of the overhead to be optimized away.
</para>
+ <note>
+ <para>
+ Inlining does not work if <productname>PostgreSQL</productname> is built using
+ <application>Meson</application> with
+ <link linkend="configure-with-llvm-meson"><option>-Dllvm</option></link>,
+ because the <productname>LLVM</productname> bitcode is not built,
+ regardless of whether <command>EXPLAIN</command> shows "Inlining true".
+ See <xref linkend="jit-extensibility-bitcode"/> for more details about bitcode.
+ </para>
+ </note>
</sect2>
<sect2 id="jit-optimization">
@@ -133,7 +144,7 @@
<para>
If <xref linkend="guc-jit"/> is set to <literal>off</literal>, or if no
<acronym>JIT</acronym> implementation is available (for example because
- the server was compiled without <literal>--with-llvm</literal>),
+ the server was compiled without <option>--with-llvm</option>),
<acronym>JIT</acronym> will not be performed, even if it would be
beneficial based on the above criteria. Setting <xref linkend="guc-jit"/>
to <literal>off</literal> has effects at both plan and execution time.
--
2.43.0
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