Basic planner and executor integration for JIT.

This adds simple cost based plan time decision about whether JIT
should be performed. jit_above_cost, jit_optimize_above_cost are
compared with the total cost of a plan, and if the cost is above them
JIT is performed / optimization is performed respectively.

For that PlannedStmt and EState have a jitFlags (es_jit_flags) field
that stores information about what JIT operations should be performed.

EState now also has a new es_jit field, which can store a
JitContext. When there are no errors the context is released in
standard_ExecutorEnd().

It is likely that the default values for jit_[optimize_]above_cost
will need to be adapted further, but in my test these values seem to
work reasonably.

Author: Andres Freund, with feedback by Peter Eisentraut
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

3 files changed, 14 insertions, 0 deletions

diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 91ba939bdca..890067757c0 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -48,6 +48,7 @@
 #include "commands/trigger.h"
 #include "executor/execdebug.h"
 #include "foreign/fdwapi.h"
+#include "jit/jit.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "optimizer/clauses.h"
@@ -249,6 +250,9 @@ standard_ExecutorStart(QueryDesc *queryDesc, int eflags)
 	estate->es_top_eflags = eflags;
 	estate->es_instrument = queryDesc->instrument_options;
 
+	if (queryDesc->plannedstmt)
+		estate->es_jit_flags = queryDesc->plannedstmt->jitFlags;
+
 	/*
 	 * Set up an AFTER-trigger statement context, unless told not to, or
 	 * unless it's EXPLAIN-only mode (when ExecutorFinish won't be called).
@@ -496,6 +500,10 @@ standard_ExecutorEnd(QueryDesc *queryDesc)
 	UnregisterSnapshot(estate->es_snapshot);
 	UnregisterSnapshot(estate->es_crosscheck_snapshot);
 
+	/* release JIT context, if allocated */
+	if (estate->es_jit)
+		jit_release_context(estate->es_jit);
+
 	/*
 	 * Must switch out of context before destroying it
 	 */
diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c
index 14b0b89463c..52f1a96db5f 100644
--- a/src/backend/executor/execParallel.c
+++ b/src/backend/executor/execParallel.c
@@ -73,6 +73,7 @@ typedef struct FixedParallelExecutorState
 	int64		tuples_needed;	/* tuple bound, see ExecSetTupleBound */
 	dsa_pointer param_exec;
 	int			eflags;
+	int			jit_flags;
 } FixedParallelExecutorState;
 
 /*
@@ -680,6 +681,7 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate,
 	fpes->tuples_needed = tuples_needed;
 	fpes->param_exec = InvalidDsaPointer;
 	fpes->eflags = estate->es_top_eflags;
+	fpes->jit_flags = estate->es_jit_flags;
 	shm_toc_insert(pcxt->toc, PARALLEL_KEY_EXECUTOR_FIXED, fpes);
 
 	/* Store query string */
@@ -1287,6 +1289,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 	area = dsa_attach_in_place(area_space, seg);
 
 	/* Start up the executor */
+	queryDesc->plannedstmt->jitFlags = fpes->jit_flags;
 	ExecutorStart(queryDesc, fpes->eflags);
 
 	/* Special executor initialization steps for parallel workers */
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index a8ae37ebc80..14b07b5d449 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -158,6 +158,9 @@ CreateExecutorState(void)
 
 	estate->es_use_parallel_mode = false;
 
+	estate->es_jit_flags = 0;
+	estate->es_jit = NULL;
+
 	/*
 	 * Return the executor state structure
 	 */