diff options
| -rw-r--r-- | doc/src/sgml/config.sgml | 2 | ||||
| -rw-r--r-- | doc/src/sgml/jit.sgml | 4 | ||||
| -rw-r--r-- | src/backend/jit/README | 14 |
3 files changed, 13 insertions, 7 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index dc9ed22eb41..e7d408824e2 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7498,7 +7498,7 @@ SET XML OPTION { DOCUMENT | CONTENT }; 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. diff --git a/doc/src/sgml/jit.sgml b/doc/src/sgml/jit.sgml index f59e4923e14..ece259b5b4b 100644 --- a/doc/src/sgml/jit.sgml +++ b/doc/src/sgml/jit.sgml @@ -32,9 +32,9 @@ </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> diff --git a/src/backend/jit/README b/src/backend/jit/README index b37dcbe0c16..bfed319189c 100644 --- a/src/backend/jit/README +++ b/src/backend/jit/README @@ -74,7 +74,7 @@ the shared library providing JIT support can be loaded (i.e. postgres 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". @@ -174,7 +174,7 @@ least a few postgres types. While it is possible to inform LLVM about 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. @@ -232,10 +232,16 @@ an ExprState, rather than absolute pointers into memory. 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 =========== |