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-rw-r--r--src/backend/commands/explain.c107
1 files changed, 81 insertions, 26 deletions
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 0d1ecc2a3ed..5d06fa4ea65 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -96,6 +96,8 @@ static void show_sort_group_keys(PlanState *planstate, const char *qlabel,
List *ancestors, ExplainState *es);
static void show_sortorder_options(StringInfo buf, Node *sortexpr,
Oid sortOperator, Oid collation, bool nullsFirst);
+static void show_tablesample(TableSampleClause *tsc, PlanState *planstate,
+ List *ancestors, ExplainState *es);
static void show_sort_info(SortState *sortstate, ExplainState *es);
static void show_hash_info(HashState *hashstate, ExplainState *es);
static void show_tidbitmap_info(BitmapHeapScanState *planstate,
@@ -116,7 +118,7 @@ static void ExplainMemberNodes(List *plans, PlanState **planstates,
static void ExplainSubPlans(List *plans, List *ancestors,
const char *relationship, ExplainState *es);
static void ExplainCustomChildren(CustomScanState *css,
- List *ancestors, ExplainState *es);
+ 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,
@@ -730,6 +732,7 @@ ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
switch (nodeTag(plan))
{
case T_SeqScan:
+ case T_SampleScan:
case T_IndexScan:
case T_IndexOnlyScan:
case T_BitmapHeapScan:
@@ -739,7 +742,6 @@ ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
case T_ValuesScan:
case T_CteScan:
case T_WorkTableScan:
- case T_SampleScan:
*rels_used = bms_add_member(*rels_used,
((Scan *) plan)->scanrelid);
break;
@@ -935,6 +937,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
case T_SeqScan:
pname = sname = "Seq Scan";
break;
+ case T_SampleScan:
+ pname = sname = "Sample Scan";
+ break;
case T_IndexScan:
pname = sname = "Index Scan";
break;
@@ -976,23 +981,6 @@ ExplainNode(PlanState *planstate, List *ancestors,
else
pname = sname;
break;
- case T_SampleScan:
- {
- /*
- * Fetch the tablesample method name from RTE.
- *
- * It would be nice to also show parameters, but since we
- * support arbitrary expressions as parameter it might get
- * quite messy.
- */
- RangeTblEntry *rte;
-
- rte = rt_fetch(((SampleScan *) plan)->scanrelid, es->rtable);
- custom_name = get_tablesample_method_name(rte->tablesample->tsmid);
- pname = psprintf("Sample Scan (%s)", custom_name);
- sname = "Sample Scan";
- }
- break;
case T_Material:
pname = sname = "Materialize";
break;
@@ -1101,6 +1089,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
switch (nodeTag(plan))
{
case T_SeqScan:
+ case T_SampleScan:
case T_BitmapHeapScan:
case T_TidScan:
case T_SubqueryScan:
@@ -1115,9 +1104,6 @@ ExplainNode(PlanState *planstate, List *ancestors,
if (((Scan *) plan)->scanrelid > 0)
ExplainScanTarget((Scan *) plan, es);
break;
- case T_SampleScan:
- ExplainScanTarget((Scan *) plan, es);
- break;
case T_IndexScan:
{
IndexScan *indexscan = (IndexScan *) plan;
@@ -1363,12 +1349,15 @@ ExplainNode(PlanState *planstate, List *ancestors,
if (es->analyze)
show_tidbitmap_info((BitmapHeapScanState *) planstate, es);
break;
+ case T_SampleScan:
+ show_tablesample(((SampleScan *) plan)->tablesample,
+ planstate, ancestors, es);
+ /* FALL THRU to print additional fields the same as SeqScan */
case T_SeqScan:
case T_ValuesScan:
case T_CteScan:
case T_WorkTableScan:
case T_SubqueryScan:
- case T_SampleScan:
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
@@ -2110,6 +2099,72 @@ show_sortorder_options(StringInfo buf, Node *sortexpr,
}
/*
+ * Show TABLESAMPLE properties
+ */
+static void
+show_tablesample(TableSampleClause *tsc, PlanState *planstate,
+ List *ancestors, ExplainState *es)
+{
+ List *context;
+ bool useprefix;
+ char *method_name;
+ List *params = NIL;
+ char *repeatable;
+ ListCell *lc;
+
+ /* Set up deparsing context */
+ context = set_deparse_context_planstate(es->deparse_cxt,
+ (Node *) planstate,
+ ancestors);
+ useprefix = list_length(es->rtable) > 1;
+
+ /* Get the tablesample method name */
+ method_name = get_func_name(tsc->tsmhandler);
+
+ /* Deparse parameter expressions */
+ foreach(lc, tsc->args)
+ {
+ Node *arg = (Node *) lfirst(lc);
+
+ params = lappend(params,
+ deparse_expression(arg, context,
+ useprefix, false));
+ }
+ if (tsc->repeatable)
+ repeatable = deparse_expression((Node *) tsc->repeatable, context,
+ useprefix, false);
+ else
+ repeatable = NULL;
+
+ /* Print results */
+ if (es->format == EXPLAIN_FORMAT_TEXT)
+ {
+ bool first = true;
+
+ appendStringInfoSpaces(es->str, es->indent * 2);
+ appendStringInfo(es->str, "Sampling: %s (", method_name);
+ foreach(lc, params)
+ {
+ if (!first)
+ appendStringInfoString(es->str, ", ");
+ appendStringInfoString(es->str, (const char *) lfirst(lc));
+ first = false;
+ }
+ appendStringInfoChar(es->str, ')');
+ if (repeatable)
+ appendStringInfo(es->str, " REPEATABLE (%s)", repeatable);
+ appendStringInfoChar(es->str, '\n');
+ }
+ else
+ {
+ ExplainPropertyText("Sampling Method", method_name, es);
+ ExplainPropertyList("Sampling Parameters", params, es);
+ if (repeatable)
+ ExplainPropertyText("Repeatable Seed", repeatable, es);
+ }
+}
+
+/*
* If it's EXPLAIN ANALYZE, show tuplesort stats for a sort node
*/
static void
@@ -2366,13 +2421,13 @@ ExplainTargetRel(Plan *plan, Index rti, ExplainState *es)
switch (nodeTag(plan))
{
case T_SeqScan:
+ case T_SampleScan:
case T_IndexScan:
case T_IndexOnlyScan:
case T_BitmapHeapScan:
case T_TidScan:
case T_ForeignScan:
case T_CustomScan:
- case T_SampleScan:
case T_ModifyTable:
/* Assert it's on a real relation */
Assert(rte->rtekind == RTE_RELATION);
@@ -2663,9 +2718,9 @@ ExplainCustomChildren(CustomScanState *css, List *ancestors, ExplainState *es)
{
ListCell *cell;
const char *label =
- (list_length(css->custom_ps) != 1 ? "children" : "child");
+ (list_length(css->custom_ps) != 1 ? "children" : "child");
- foreach (cell, css->custom_ps)
+ foreach(cell, css->custom_ps)
ExplainNode((PlanState *) lfirst(cell), ancestors, label, NULL, es);
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-25 15:32:06 +0000