From 5ca611841bcd37c7ee8448c46c8398ef8d8edcc4 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 26 Jun 2015 09:40:47 -0400
Subject: [PATCH] Improve handling of CustomPath/CustomPlan(State) children.
Allow CustomPath to have a list of paths, CustomPlan a list of plans,
and CustomPlanState a list of planstates known to the core system, so
that custom path/plan providers can more reasonably use this
infrastructure for nodes with multiple children.
KaiGai Kohei, per a design suggestion from Tom Lane, with some
further kibitzing by me.
---
doc/src/sgml/custom-scan.sgml | 10 +++++++++-
src/backend/commands/explain.c | 22 ++++++++++++++++++++++
src/backend/optimizer/plan/createplan.c | 13 ++++++++++++-
src/backend/optimizer/plan/setrefs.c | 8 ++++++++
src/backend/optimizer/plan/subselect.c | 25 +++++++++++++++++++++----
src/include/nodes/execnodes.h | 1 +
src/include/nodes/plannodes.h | 1 +
src/include/nodes/relation.h | 4 +++-
8 files changed, 77 insertions(+), 7 deletions(-)
diff --git a/doc/src/sgml/custom-scan.sgml b/doc/src/sgml/custom-scan.sgml
index 62a8a3305bb..dc327b11b21 100644
--- a/doc/src/sgml/custom-scan.sgml
+++ b/doc/src/sgml/custom-scan.sgml
@@ -60,6 +60,7 @@ typedef struct CustomPath
{
Path path;
uint32 flags;
+ List *custom_paths;
List *custom_private;
const CustomPathMethods *methods;
} CustomPath;
@@ -73,6 +74,9 @@ typedef struct CustomPath
<literal>CUSTOMPATH_SUPPORT_BACKWARD_SCAN</> if the custom path can support
a backward scan and <literal>CUSTOMPATH_SUPPORT_MARK_RESTORE</> if it
can support mark and restore. Both capabilities are optional.
+ An optional <structfield>custom_paths</> is a list of <structname>Path</>
+ nodes used by this custom-path node; these will be transformed into
+ <structname>Plan</> nodes by planner.
<structfield>custom_private</> can be used to store the custom path's
private data. Private data should be stored in a form that can be handled
by <literal>nodeToString</>, so that debugging routines that attempt to
@@ -112,7 +116,8 @@ Plan *(*PlanCustomPath) (PlannerInfo *root,
RelOptInfo *rel,
CustomPath *best_path,
List *tlist,
- List *clauses);
+ List *clauses,
+ List *custom_plans);
</programlisting>
Convert a custom path to a finished plan. The return value will generally
be a <literal>CustomScan</> object, which the callback must allocate and
@@ -145,6 +150,7 @@ typedef struct CustomScan
{
Scan scan;
uint32 flags;
+ List *custom_plans;
List *custom_exprs;
List *custom_private;
List *custom_scan_tlist;
@@ -159,6 +165,8 @@ typedef struct CustomScan
estimated costs, target lists, qualifications, and so on.
<structfield>flags</> is a bitmask with the same meaning as in
<structname>CustomPath</>.
+ <structfield>custom_plans</> can be used to store child
+ <structname>Plan</> nodes.
<structfield>custom_exprs</> should be used to
store expression trees that will need to be fixed up by
<filename>setrefs.c</> and <filename>subselect.c</>, while
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index a82c6ff7b4d..0d1ecc2a3ed 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -115,6 +115,8 @@ static void ExplainMemberNodes(List *plans, PlanState **planstates,
List *ancestors, ExplainState *es);
static void ExplainSubPlans(List *plans, List *ancestors,
const char *relationship, ExplainState *es);
+static void ExplainCustomChildren(CustomScanState *css,
+ List *ancestors, ExplainState *es);
static void ExplainProperty(const char *qlabel, const char *value,
bool numeric, ExplainState *es);
static void ExplainOpenGroup(const char *objtype, const char *labelname,
@@ -1624,6 +1626,8 @@ ExplainNode(PlanState *planstate, List *ancestors,
IsA(plan, BitmapAnd) ||
IsA(plan, BitmapOr) ||
IsA(plan, SubqueryScan) ||
+ (IsA(planstate, CustomScanState) &&
+ ((CustomScanState *) planstate)->custom_ps != NIL) ||
planstate->subPlan;
if (haschildren)
{
@@ -1678,6 +1682,10 @@ ExplainNode(PlanState *planstate, List *ancestors,
ExplainNode(((SubqueryScanState *) planstate)->subplan, ancestors,
"Subquery", NULL, es);
break;
+ case T_CustomScan:
+ ExplainCustomChildren((CustomScanState *) planstate,
+ ancestors, es);
+ break;
default:
break;
}
@@ -2647,6 +2655,20 @@ ExplainSubPlans(List *plans, List *ancestors,
}
}
+/*
+ * Explain a list of children of a CustomScan.
+ */
+static void
+ExplainCustomChildren(CustomScanState *css, List *ancestors, ExplainState *es)
+{
+ ListCell *cell;
+ const char *label =
+ (list_length(css->custom_ps) != 1 ? "children" : "child");
+
+ foreach (cell, css->custom_ps)
+ ExplainNode((PlanState *) lfirst(cell), ancestors, label, NULL, es);
+}
+
/*
* Explain a property, such as sort keys or targets, that takes the form of
* a list of unlabeled items. "data" is a list of C strings.
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index a3482def643..dc2dcbf93f7 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -2157,6 +2157,16 @@ create_customscan_plan(PlannerInfo *root, CustomPath *best_path,
{
CustomScan *cplan;
RelOptInfo *rel = best_path->path.parent;
+ List *custom_plans = NIL;
+ ListCell *lc;
+
+ /* Recursively transform child paths. */
+ foreach (lc, best_path->custom_paths)
+ {
+ Plan *plan = create_plan_recurse(root, (Path *) lfirst(lc));
+
+ custom_plans = lappend(custom_plans, plan);
+ }
/*
* Sort clauses into the best execution order, although custom-scan
@@ -2172,7 +2182,8 @@ create_customscan_plan(PlannerInfo *root, CustomPath *best_path,
rel,
best_path,
tlist,
- scan_clauses);
+ scan_clauses,
+ custom_plans);
Assert(IsA(cplan, CustomScan));
/*
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index a7f65dd529f..c0641a7cfb0 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -1151,6 +1151,8 @@ set_customscan_references(PlannerInfo *root,
CustomScan *cscan,
int rtoffset)
{
+ ListCell *lc;
+
/* Adjust scanrelid if it's valid */
if (cscan->scan.scanrelid > 0)
cscan->scan.scanrelid += rtoffset;
@@ -1194,6 +1196,12 @@ set_customscan_references(PlannerInfo *root,
fix_scan_list(root, cscan->custom_exprs, rtoffset);
}
+ /* Adjust child plan-nodes recursively, if needed */
+ foreach (lc, cscan->custom_plans)
+ {
+ lfirst(lc) = set_plan_refs(root, (Plan *) lfirst(lc), rtoffset);
+ }
+
/* Adjust custom_relids if needed */
if (rtoffset > 0)
{
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index f80abb494c7..4708b87f330 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -2373,10 +2373,27 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params,
break;
case T_CustomScan:
- finalize_primnode((Node *) ((CustomScan *) plan)->custom_exprs,
- &context);
- /* We assume custom_scan_tlist cannot contain Params */
- context.paramids = bms_add_members(context.paramids, scan_params);
+ {
+ CustomScan *cscan = (CustomScan *) plan;
+ ListCell *lc;
+
+ finalize_primnode((Node *) cscan->custom_exprs,
+ &context);
+ /* We assume custom_scan_tlist cannot contain Params */
+ context.paramids =
+ bms_add_members(context.paramids, scan_params);
+
+ /* child nodes if any */
+ foreach (lc, cscan->custom_plans)
+ {
+ context.paramids =
+ bms_add_members(context.paramids,
+ finalize_plan(root,
+ (Plan *) lfirst(lc),
+ valid_params,
+ scan_params));
+ }
+ }
break;
case T_ModifyTable:
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index db5bd7faf04..541ee187356 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1616,6 +1616,7 @@ typedef struct CustomScanState
{
ScanState ss;
uint32 flags; /* mask of CUSTOMPATH_* flags, see relation.h */
+ List *custom_ps; /* list of child PlanState nodes, if any */
const CustomExecMethods *methods;
} CustomScanState;
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index d967219c0b5..5f538f3e8cc 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -550,6 +550,7 @@ typedef struct CustomScan
{
Scan scan;
uint32 flags; /* mask of CUSTOMPATH_* flags, see relation.h */
+ List *custom_plans; /* list of Plan nodes, if any */
List *custom_exprs; /* expressions that custom code may evaluate */
List *custom_private; /* private data for custom code */
List *custom_scan_tlist; /* optional tlist describing scan
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 33b08745702..cb916ea8e14 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -929,7 +929,8 @@ typedef struct CustomPathMethods
RelOptInfo *rel,
struct CustomPath *best_path,
List *tlist,
- List *clauses);
+ List *clauses,
+ List *custom_plans);
/* Optional: print additional fields besides "private" */
void (*TextOutCustomPath) (StringInfo str,
const struct CustomPath *node);
@@ -939,6 +940,7 @@ typedef struct CustomPath
{
Path path;
uint32 flags; /* mask of CUSTOMPATH_* flags, see above */
+ List *custom_paths; /* list of child Path nodes, if any */
List *custom_private;
const CustomPathMethods *methods;
} CustomPath;
--
GitLab