used. The built-in default is <literal>llvmjit</literal>.
</para>
<para>
- If set to a non-existent library <acronym>JIT</acronym> will not
+ If set to a non-existent library <acronym>JIT</acronym> will not be
available, but no error will be raised. This allows JIT support to be
installed separately from the main
<productname>PostgreSQL</productname> package.
</para>
<para>
- <productname>PostgreSQL</productname> has builtin support perform
+ <productname>PostgreSQL</productname> has builtin support to perform
<acronym>JIT</acronym> using <ulink
- url="https://llvm.org/"><productname>LLVM</productname></ulink> when built
+ url="https://llvm.org/"><productname>LLVM</productname></ulink> when
<productname>PostgreSQL</productname> was built with
<literal>--with-llvm</literal> (see <xref linkend="configure-with-llvm"/>).
</para>
was compiled with LLVM support and the shared library is installed),
the task of JIT compiling an expression gets handed of to shared
library. This obviously requires that the function in jit.c is allowed
-to fail in case not JIT provider can be loaded.
+to fail in case no JIT provider can be loaded.
Which shared library is loaded is determined by the jit_provider GUC,
defaulting to "llvmjit".
type definitions by recreating them manually in C code, that is failure
prone and labor intensive.
-Instead the is one small file (llvmjit_types.c) which references each of
+Instead there is one small file (llvmjit_types.c) which references each of
the types required for JITing. That file is translated to bitcode at
compile time, and loaded when LLVM is initialized in a backend.
Once that is addressed, adding an LRU cache that's keyed by the
generated LLVM IR will allow to use optimized functions even for
-shorter functions.
+faster queries.
A longer term project is to move expression compilation to the planner
-stage, allowing to tie
+stage, allowing e.g. to tie compiled expressions to prepared
+statements.
+
+An even more advanced approach would be to use JIT with few
+optimizations initially, and build an optimized version in the
+background. But that's even further off.
+
What to JIT
===========