On Sun, Jan 24, 2010 at 12:30 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Robert Haas <robertmh...@gmail.com> writes:
>> On Sun, Jan 24, 2010 at 12:06 AM, Jaime Casanova
>>> why not let it go in ANALYZE, just as the sort info
>
>> It's kinda long-winded - it adds like 4 extra lines for each hash
>> join. I don't think I want to add that much clutter to regular E-A
>> output.
>
> Well, that would only happen if you're deliberately obtuse about the
> formatting. The sort code manages to fit all the extra on one line,
> and I don't see why hash couldn't.
OK, here's a new version.
...Robert
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -20,6 +20,7 @@
#include "commands/explain.h"
#include "commands/prepare.h"
#include "commands/trigger.h"
+#include "executor/hashjoin.h"
#include "executor/instrument.h"
#include "optimizer/clauses.h"
#include "optimizer/planner.h"
@@ -67,6 +68,7 @@ static void show_upper_qual(List *qual, const char *qlabel, Plan *plan,
ExplainState *es);
static void show_sort_keys(Plan *sortplan, ExplainState *es);
static void show_sort_info(SortState *sortstate, ExplainState *es);
+static void show_hash_info(HashState *hashstate, ExplainState *es);
static const char *explain_get_index_name(Oid indexId);
static void ExplainScanTarget(Scan *plan, ExplainState *es);
static void ExplainMemberNodes(List *plans, PlanState **planstate,
@@ -1052,6 +1054,9 @@ ExplainNode(Plan *plan, PlanState *planstate,
"One-Time Filter", plan, es);
show_upper_qual(plan->qual, "Filter", plan, es);
break;
+ case T_Hash:
+ show_hash_info((HashState *) planstate, es);
+ break;
default:
break;
}
@@ -1405,6 +1410,47 @@ show_sort_info(SortState *sortstate, ExplainState *es)
}
/*
+ * Show information on hash buckets/batches.
+ */
+static void
+show_hash_info(HashState *hashstate, ExplainState *es)
+{
+ HashJoinTable hashtable;
+
+ Assert(IsA(hashstate, HashState));
+ hashtable = hashstate->hashtable;
+
+ if (hashtable)
+ {
+ long spacePeakKb = (hashtable->spacePeak + 1023) / 1024;
+ if (es->format != EXPLAIN_FORMAT_TEXT)
+ {
+ ExplainPropertyLong("Hash Buckets", hashtable->nbuckets, es);
+ ExplainPropertyLong("Hash Batches", hashtable->nbatch, es);
+ ExplainPropertyLong("Original Hash Batches",
+ hashtable->nbatch_original, es);
+ ExplainPropertyLong("Peak Memory Usage", spacePeakKb, es);
+ }
+ else if (hashtable->nbatch_original != hashtable->nbatch)
+ {
+ appendStringInfoSpaces(es->str, es->indent * 2);
+ appendStringInfo(es->str,
+ "Buckets: %d Batches: %d (originally %d) Memory Usage: %ldkB\n",
+ hashtable->nbuckets, hashtable->nbatch,
+ hashtable->nbatch_original, spacePeakKb);
+ }
+ else
+ {
+ appendStringInfoSpaces(es->str, es->indent * 2);
+ appendStringInfo(es->str,
+ "Buckets: %d Batches: %d Memory Usage: %ldkB\n",
+ hashtable->nbuckets, hashtable->nbatch,
+ spacePeakKb);
+ }
+ }
+}
+
+/*
* Fetch the name of an index in an EXPLAIN
*
* We allow plugins to get control here so that plans involving hypothetical
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -287,6 +287,7 @@ ExecHashTableCreate(Hash *node, List *hashOperators)
hashtable->innerBatchFile = NULL;
hashtable->outerBatchFile = NULL;
hashtable->spaceUsed = 0;
+ hashtable->spacePeak = 0;
hashtable->spaceAllowed = work_mem * 1024L;
hashtable->spaceUsedSkew = 0;
hashtable->spaceAllowedSkew =
@@ -719,6 +720,8 @@ ExecHashTableInsert(HashJoinTable hashtable,
hashTuple->next = hashtable->buckets[bucketno];
hashtable->buckets[bucketno] = hashTuple;
hashtable->spaceUsed += hashTupleSize;
+ if (hashtable->spaceUsed > hashtable->spacePeak)
+ hashtable->spacePeak = hashtable->spaceUsed;
if (hashtable->spaceUsed > hashtable->spaceAllowed)
ExecHashIncreaseNumBatches(hashtable);
}
@@ -1071,6 +1074,8 @@ ExecHashBuildSkewHash(HashJoinTable hashtable, Hash *node, int mcvsToUse)
+ mcvsToUse * sizeof(int);
hashtable->spaceUsedSkew += nbuckets * sizeof(HashSkewBucket *)
+ mcvsToUse * sizeof(int);
+ if (hashtable->spaceUsed > hashtable->spacePeak)
+ hashtable->spacePeak = hashtable->spaceUsed;
/*
* Create a skew bucket for each MCV hash value.
@@ -1119,6 +1124,8 @@ ExecHashBuildSkewHash(HashJoinTable hashtable, Hash *node, int mcvsToUse)
hashtable->nSkewBuckets++;
hashtable->spaceUsed += SKEW_BUCKET_OVERHEAD;
hashtable->spaceUsedSkew += SKEW_BUCKET_OVERHEAD;
+ if (hashtable->spaceUsed > hashtable->spacePeak)
+ hashtable->spacePeak = hashtable->spaceUsed;
}
free_attstatsslot(node->skewColType,
@@ -1205,6 +1212,8 @@ ExecHashSkewTableInsert(HashJoinTable hashtable,
/* Account for space used, and back off if we've used too much */
hashtable->spaceUsed += hashTupleSize;
hashtable->spaceUsedSkew += hashTupleSize;
+ if (hashtable->spaceUsed > hashtable->spacePeak)
+ hashtable->spacePeak = hashtable->spaceUsed;
while (hashtable->spaceUsedSkew > hashtable->spaceAllowedSkew)
ExecHashRemoveNextSkewBucket(hashtable);
--- a/src/include/executor/hashjoin.h
+++ b/src/include/executor/hashjoin.h
@@ -149,6 +149,7 @@ typedef struct HashJoinTableData
Size spaceUsed; /* memory space currently used by tuples */
Size spaceAllowed; /* upper limit for space used */
+ Size spacePeak; /* peak space used */
Size spaceUsedSkew; /* skew hash table's current space usage */
Size spaceAllowedSkew; /* upper limit for skew hashtable */
--
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