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JIT tuple deforming in LLVM JIT provider.

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Performing JIT compilation for deforming gains performance benefits
over unJITed deforming from compile-time knowledge of the tuple
descriptor. Fixed column widths, NOT NULLness, etc can be taken
advantage of.

Right now the JITed deforming is only used when deforming tuples as
part of expression evaluation (and obviously only if the descriptor is
known). It's likely to be beneficial in other cases, too.

By default tuple deforming is JITed whenever an expression is JIT
compiled. There's a separate boolean GUC controlling it, but that's
expected to be primarily useful for development and benchmarking.

Docs will follow in a later commit containing docs for the whole JIT
feature.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
This commit is contained in:
Andres Freund
2018-03-26 12:57:19 -07:00
parent 64f85894ad
commit 32af96b2b1
17 changed files with 827 additions and 3 deletions
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2
src/include/jit/jit.h
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@@ -21,6 +21,7 @@
#define PGJIT_OPT3 1 << 1
/* reserved for PGJIT_INLINE */
#define PGJIT_EXPR 1 << 3
#define PGJIT_DEFORM 1 << 4
typedef struct JitContext
@@ -67,6 +68,7 @@ extern bool jit_debugging_support;
extern bool jit_dump_bitcode;
extern bool jit_expressions;
extern bool jit_profiling_support;
extern bool jit_tuple_deforming;
extern double jit_above_cost;
extern double jit_optimize_above_cost;