* of course). A non-strict finalfunc can make its own choice of
* what to return for a NULL ending transvalue.
*
- * When the transvalue datatype is pass-by-reference, we have to be
- * careful to ensure that the values survive across tuple cycles yet
- * are not allowed to accumulate until end of query. We do this by
- * "ping-ponging" between two memory contexts; successive calls to the
- * transfunc are executed in alternate contexts, passing the previous
- * transvalue that is in the other context. At the beginning of each
- * tuple cycle we can reset the current output context to avoid memory
- * usage growth. Note: we must use MemoryContextContains() to check
- * whether the transfunc has perhaps handed us back one of its input
- * values rather than a freshly palloc'd value; if so, we copy the value
- * to the context we want it in.
+ * We compute aggregate input expressions and run the transition functions
+ * in a temporary econtext (aggstate->tmpcontext). This is reset at
+ * least once per input tuple, so when the transvalue datatype is
+ * pass-by-reference, we have to be careful to copy it into a longer-lived
+ * memory context, and free the prior value to avoid memory leakage.
+ * We store transvalues in the memory context aggstate->aggcontext,
+ * which is also used for the hashtable structures in AGG_HASHED mode.
+ * The node's regular econtext (aggstate->csstate.cstate.cs_ExprContext)
+ * is used to run finalize functions and compute the output tuple;
+ * this context can be reset once per output tuple.
*
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.91 2002/11/06 00:00:43 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.92 2002/11/06 22:31:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "executor/executor.h"
#include "executor/nodeAgg.h"
#include "executor/nodeGroup.h"
+#include "executor/nodeHash.h"
#include "miscadmin.h"
#include "optimizer/clauses.h"
#include "parser/parse_coerce.h"
*/
Tuplesortstate *sortstate; /* sort object, if a DISTINCT agg */
+} AggStatePerAggData;
- Datum transValue;
+/*
+ * AggStatePerGroupData - per-aggregate-per-group working state
+ *
+ * These values are working state that is initialized at the start of
+ * an input tuple group and updated for each input tuple.
+ *
+ * In AGG_PLAIN and AGG_SORTED modes, we have a single array of these
+ * structs (pointed to by aggstate->pergroup); we re-use the array for
+ * each input group, if it's AGG_SORTED mode. In AGG_HASHED mode, the
+ * hash table contains an array of these structs for each tuple group.
+ *
+ * Logically, the sortstate field belongs in this struct, but we do not
+ * keep it here for space reasons: we don't support DISTINCT aggregates
+ * in AGG_HASHED mode, so there's no reason to use up a pointer field
+ * in every entry of the hashtable.
+ */
+typedef struct AggStatePerGroupData
+{
+ Datum transValue; /* current transition value */
bool transValueIsNull;
bool noTransValue; /* true if transValue not set yet */
* later input value. Only the first non-NULL input will be
* auto-substituted.
*/
-} AggStatePerAggData;
-
+} AggStatePerGroupData;
-static void initialize_aggregate(AggStatePerAgg peraggstate);
-static void advance_transition_function(AggStatePerAgg peraggstate,
- Datum newVal, bool isNull);
-static void advance_aggregates(AggState *aggstate, ExprContext *econtext);
+/*
+ * To implement hashed aggregation, we need a hashtable that stores a
+ * representative tuple and an array of AggStatePerGroup structs for each
+ * distinct set of GROUP BY column values. We compute the hash key from
+ * the GROUP BY columns.
+ */
+typedef struct AggHashEntryData
+{
+ AggHashEntry next; /* next entry in same hash bucket */
+ uint32 hashkey; /* exact hash key of this entry */
+ HeapTuple firstTuple; /* copy of first tuple in this group */
+ /* per-aggregate transition status array - must be last! */
+ AggStatePerGroupData pergroup[1]; /* VARIABLE LENGTH ARRAY */
+} AggHashEntryData; /* VARIABLE LENGTH STRUCT */
+
+typedef struct AggHashTableData
+{
+ int nbuckets; /* number of buckets in hash table */
+ AggHashEntry buckets[1]; /* VARIABLE LENGTH ARRAY */
+} AggHashTableData; /* VARIABLE LENGTH STRUCT */
+
+
+static void initialize_aggregates(AggState *aggstate,
+ AggStatePerAgg peragg,
+ AggStatePerGroup pergroup);
+static void advance_transition_function(AggState *aggstate,
+ AggStatePerAgg peraggstate,
+ AggStatePerGroup pergroupstate,
+ Datum newVal, bool isNull);
+static void advance_aggregates(AggState *aggstate, AggStatePerGroup pergroup);
static void process_sorted_aggregate(AggState *aggstate,
- AggStatePerAgg peraggstate);
-static void finalize_aggregate(AggStatePerAgg peraggstate,
- Datum *resultVal, bool *resultIsNull);
+ AggStatePerAgg peraggstate,
+ AggStatePerGroup pergroupstate);
+static void finalize_aggregate(AggState *aggstate,
+ AggStatePerAgg peraggstate,
+ AggStatePerGroup pergroupstate,
+ Datum *resultVal, bool *resultIsNull);
+static void build_hash_table(Agg *node);
+static AggHashEntry lookup_hash_entry(Agg *node, TupleTableSlot *slot);
+static TupleTableSlot *agg_retrieve_direct(Agg *node);
+static void agg_fill_hash_table(Agg *node);
+static TupleTableSlot *agg_retrieve_hash_table(Agg *node);
static Datum GetAggInitVal(Datum textInitVal, Oid transtype);
/*
- * Initialize one aggregate for a new set of input values.
+ * Initialize all aggregates for a new group of input values.
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
-initialize_aggregate(AggStatePerAgg peraggstate)
+initialize_aggregates(AggState *aggstate,
+ AggStatePerAgg peragg,
+ AggStatePerGroup pergroup)
{
- Aggref *aggref = peraggstate->aggref;
+ int aggno;
- /*
- * Start a fresh sort operation for each DISTINCT aggregate.
- */
- if (aggref->aggdistinct)
+ for (aggno = 0; aggno < aggstate->numaggs; aggno++)
{
+ AggStatePerAgg peraggstate = &peragg[aggno];
+ AggStatePerGroup pergroupstate = &pergroup[aggno];
+ Aggref *aggref = peraggstate->aggref;
+
/*
- * In case of rescan, maybe there could be an uncompleted sort
- * operation? Clean it up if so.
+ * Start a fresh sort operation for each DISTINCT aggregate.
*/
- if (peraggstate->sortstate)
- tuplesort_end(peraggstate->sortstate);
+ if (aggref->aggdistinct)
+ {
+ /*
+ * In case of rescan, maybe there could be an uncompleted sort
+ * operation? Clean it up if so.
+ */
+ if (peraggstate->sortstate)
+ tuplesort_end(peraggstate->sortstate);
- peraggstate->sortstate =
- tuplesort_begin_datum(peraggstate->inputType,
- peraggstate->sortOperator,
- false);
- }
+ peraggstate->sortstate =
+ tuplesort_begin_datum(peraggstate->inputType,
+ peraggstate->sortOperator,
+ false);
+ }
- /*
- * (Re)set transValue to the initial value.
- *
- * Note that when the initial value is pass-by-ref, we just reuse it
- * without copying for each group. Hence, transition function had
- * better not scribble on its input, or it will fail for GROUP BY!
- */
- peraggstate->transValue = peraggstate->initValue;
- peraggstate->transValueIsNull = peraggstate->initValueIsNull;
+ /*
+ * (Re)set transValue to the initial value.
+ *
+ * Note that when the initial value is pass-by-ref, we must copy it
+ * (into the aggcontext) since we will pfree the transValue later.
+ */
+ if (peraggstate->initValueIsNull)
+ pergroupstate->transValue = peraggstate->initValue;
+ else
+ {
+ MemoryContext oldContext;
- /*
- * If the initial value for the transition state doesn't exist in the
- * pg_aggregate table then we will let the first non-NULL value
- * returned from the outer procNode become the initial value. (This is
- * useful for aggregates like max() and min().) The noTransValue flag
- * signals that we still need to do this.
- */
- peraggstate->noTransValue = peraggstate->initValueIsNull;
+ oldContext = MemoryContextSwitchTo(aggstate->aggcontext);
+ pergroupstate->transValue = datumCopy(peraggstate->initValue,
+ peraggstate->transtypeByVal,
+ peraggstate->transtypeLen);
+ MemoryContextSwitchTo(oldContext);
+ }
+ pergroupstate->transValueIsNull = peraggstate->initValueIsNull;
+
+ /*
+ * If the initial value for the transition state doesn't exist in the
+ * pg_aggregate table then we will let the first non-NULL value
+ * returned from the outer procNode become the initial value. (This is
+ * useful for aggregates like max() and min().) The noTransValue flag
+ * signals that we still need to do this.
+ */
+ pergroupstate->noTransValue = peraggstate->initValueIsNull;
+ }
}
/*
* Given a new input value, advance the transition function of an aggregate.
*
- * When called, CurrentMemoryContext should be the context we want the
- * transition function result to be delivered into on this cycle.
+ * It doesn't matter which memory context this is called in.
*/
static void
-advance_transition_function(AggStatePerAgg peraggstate,
+advance_transition_function(AggState *aggstate,
+ AggStatePerAgg peraggstate,
+ AggStatePerGroup pergroupstate,
Datum newVal, bool isNull)
{
FunctionCallInfoData fcinfo;
+ MemoryContext oldContext;
if (peraggstate->transfn.fn_strict)
{
+ /*
+ * For a strict transfn, nothing happens at a NULL input
+ * tuple; we just keep the prior transValue.
+ */
if (isNull)
- {
- /*
- * For a strict transfn, nothing happens at a NULL input
- * tuple; we just keep the prior transValue. However, if the
- * transtype is pass-by-ref, we have to copy it into the new
- * context because the old one is going to get reset.
- */
- if (!peraggstate->transValueIsNull)
- peraggstate->transValue = datumCopy(peraggstate->transValue,
- peraggstate->transtypeByVal,
- peraggstate->transtypeLen);
return;
- }
- if (peraggstate->noTransValue)
+ if (pergroupstate->noTransValue)
{
/*
* transValue has not been initialized. This is the first
* is binary-compatible with its transtype, so straight copy
* here is OK.)
*
- * We had better copy the datum if it is pass-by-ref, since the
- * given pointer may be pointing into a scan tuple that will
- * be freed on the next iteration of the scan.
+ * We must copy the datum into aggcontext if it is pass-by-ref.
+ * We do not need to pfree the old transValue, since it's NULL.
*/
- peraggstate->transValue = datumCopy(newVal,
- peraggstate->transtypeByVal,
- peraggstate->transtypeLen);
- peraggstate->transValueIsNull = false;
- peraggstate->noTransValue = false;
+ oldContext = MemoryContextSwitchTo(aggstate->aggcontext);
+ pergroupstate->transValue = datumCopy(newVal,
+ peraggstate->transtypeByVal,
+ peraggstate->transtypeLen);
+ pergroupstate->transValueIsNull = false;
+ pergroupstate->noTransValue = false;
+ MemoryContextSwitchTo(oldContext);
return;
}
- if (peraggstate->transValueIsNull)
+ if (pergroupstate->transValueIsNull)
{
/*
* Don't call a strict function with NULL inputs. Note it is
}
}
+ /* We run the transition functions in per-input-tuple memory context */
+ oldContext = MemoryContextSwitchTo(aggstate->tmpcontext->ecxt_per_tuple_memory);
+
/*
* OK to call the transition function
*
fcinfo.flinfo = &peraggstate->transfn;
fcinfo.nargs = 2;
- fcinfo.arg[0] = peraggstate->transValue;
- fcinfo.argnull[0] = peraggstate->transValueIsNull;
+ fcinfo.arg[0] = pergroupstate->transValue;
+ fcinfo.argnull[0] = pergroupstate->transValueIsNull;
fcinfo.arg[1] = newVal;
fcinfo.argnull[1] = isNull;
newVal = FunctionCallInvoke(&fcinfo);
/*
- * If the transition function was uncooperative, it may have given us
- * a pass-by-ref result that points at the scan tuple or the
- * prior-cycle working memory. Copy it into the active context if it
- * doesn't look right.
+ * If pass-by-ref datatype, must copy the new value into aggcontext and
+ * pfree the prior transValue. But if transfn returned a pointer to its
+ * first input, we don't need to do anything.
*/
- if (!peraggstate->transtypeByVal && !fcinfo.isnull &&
- !MemoryContextContains(CurrentMemoryContext,
- DatumGetPointer(newVal)))
- newVal = datumCopy(newVal,
- peraggstate->transtypeByVal,
- peraggstate->transtypeLen);
+ if (!peraggstate->transtypeByVal &&
+ DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue))
+ {
+ if (!fcinfo.isnull)
+ {
+ MemoryContextSwitchTo(aggstate->aggcontext);
+ newVal = datumCopy(newVal,
+ peraggstate->transtypeByVal,
+ peraggstate->transtypeLen);
+ }
+ if (!pergroupstate->transValueIsNull)
+ pfree(DatumGetPointer(pergroupstate->transValue));
+ }
+
+ pergroupstate->transValue = newVal;
+ pergroupstate->transValueIsNull = fcinfo.isnull;
- peraggstate->transValue = newVal;
- peraggstate->transValueIsNull = fcinfo.isnull;
+ MemoryContextSwitchTo(oldContext);
}
/*
* Advance all the aggregates for one input tuple. The input tuple
- * has been stored in econtext->ecxt_scantuple, so that it is accessible
- * to ExecEvalExpr.
+ * has been stored in tmpcontext->ecxt_scantuple, so that it is accessible
+ * to ExecEvalExpr. pergroup is the array of per-group structs to use
+ * (this might be in a hashtable entry).
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
-advance_aggregates(AggState *aggstate, ExprContext *econtext)
+advance_aggregates(AggState *aggstate, AggStatePerGroup pergroup)
{
- MemoryContext oldContext;
+ ExprContext *econtext = aggstate->tmpcontext;
int aggno;
- /*
- * Clear and select the current working context for evaluation
- * of the input expressions and transition functions at this
- * input tuple.
- */
- econtext->ecxt_per_tuple_memory = aggstate->agg_cxt[aggstate->which_cxt];
- ResetExprContext(econtext);
- oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
-
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
{
AggStatePerAgg peraggstate = &aggstate->peragg[aggno];
+ AggStatePerGroup pergroupstate = &pergroup[aggno];
Aggref *aggref = peraggstate->aggref;
Datum newVal;
bool isNull;
- newVal = ExecEvalExpr(aggref->target, econtext, &isNull, NULL);
+ newVal = ExecEvalExprSwitchContext(aggref->target, econtext,
+ &isNull, NULL);
if (aggref->aggdistinct)
{
/* in DISTINCT mode, we may ignore nulls */
if (isNull)
continue;
- /* putdatum has to be called in per-query context */
- MemoryContextSwitchTo(oldContext);
tuplesort_putdatum(peraggstate->sortstate, newVal, isNull);
- MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
}
else
{
- advance_transition_function(peraggstate, newVal, isNull);
+ advance_transition_function(aggstate, peraggstate, pergroupstate,
+ newVal, isNull);
}
}
-
- /*
- * Make the other context current so that these transition
- * results are preserved.
- */
- aggstate->which_cxt = 1 - aggstate->which_cxt;
-
- MemoryContextSwitchTo(oldContext);
}
/*
*/
static void
process_sorted_aggregate(AggState *aggstate,
- AggStatePerAgg peraggstate)
+ AggStatePerAgg peraggstate,
+ AggStatePerGroup pergroupstate)
{
Datum oldVal = (Datum) 0;
bool haveOldVal = false;
+ MemoryContext workcontext = aggstate->tmpcontext->ecxt_per_tuple_memory;
MemoryContext oldContext;
Datum newVal;
bool isNull;
continue;
/*
- * Clear and select the current working context for evaluation of
+ * Clear and select the working context for evaluation of
* the equality function and transition function.
*/
- MemoryContextReset(aggstate->agg_cxt[aggstate->which_cxt]);
- oldContext =
- MemoryContextSwitchTo(aggstate->agg_cxt[aggstate->which_cxt]);
+ MemoryContextReset(workcontext);
+ oldContext = MemoryContextSwitchTo(workcontext);
if (haveOldVal &&
DatumGetBool(FunctionCall2(&peraggstate->equalfn,
/* equal to prior, so forget this one */
if (!peraggstate->inputtypeByVal)
pfree(DatumGetPointer(newVal));
-
- /*
- * note we do NOT flip contexts in this case, so no need to
- * copy prior transValue to other context.
- */
}
else
{
- advance_transition_function(peraggstate, newVal, false);
-
- /*
- * Make the other context current so that this transition
- * result is preserved.
- */
- aggstate->which_cxt = 1 - aggstate->which_cxt;
+ advance_transition_function(aggstate, peraggstate, pergroupstate,
+ newVal, false);
/* forget the old value, if any */
if (haveOldVal && !peraggstate->inputtypeByVal)
pfree(DatumGetPointer(oldVal));
+ /* and remember the new one for subsequent equality checks */
oldVal = newVal;
haveOldVal = true;
}
/*
* Compute the final value of one aggregate.
*
- * When called, CurrentMemoryContext should be the context where we want
- * final values delivered (ie, the per-output-tuple expression context).
+ * The finalfunction will be run, and the result delivered, in the
+ * output-tuple context; caller's CurrentMemoryContext does not matter.
*/
static void
-finalize_aggregate(AggStatePerAgg peraggstate,
+finalize_aggregate(AggState *aggstate,
+ AggStatePerAgg peraggstate,
+ AggStatePerGroup pergroupstate,
Datum *resultVal, bool *resultIsNull)
{
+ MemoryContext oldContext;
+
+ oldContext = MemoryContextSwitchTo(aggstate->csstate.cstate.cs_ExprContext->ecxt_per_tuple_memory);
+
/*
* Apply the agg's finalfn if one is provided, else return transValue.
*/
MemSet(&fcinfo, 0, sizeof(fcinfo));
fcinfo.flinfo = &peraggstate->finalfn;
fcinfo.nargs = 1;
- fcinfo.arg[0] = peraggstate->transValue;
- fcinfo.argnull[0] = peraggstate->transValueIsNull;
- if (fcinfo.flinfo->fn_strict && peraggstate->transValueIsNull)
+ fcinfo.arg[0] = pergroupstate->transValue;
+ fcinfo.argnull[0] = pergroupstate->transValueIsNull;
+ if (fcinfo.flinfo->fn_strict && pergroupstate->transValueIsNull)
{
/* don't call a strict function with NULL inputs */
*resultVal = (Datum) 0;
}
else
{
- *resultVal = peraggstate->transValue;
- *resultIsNull = peraggstate->transValueIsNull;
+ *resultVal = pergroupstate->transValue;
+ *resultIsNull = pergroupstate->transValueIsNull;
}
/*
*resultVal = datumCopy(*resultVal,
peraggstate->resulttypeByVal,
peraggstate->resulttypeLen);
+
+ MemoryContextSwitchTo(oldContext);
}
+/*
+ * Initialize the hash table to empty.
+ *
+ * The hash table always lives in the aggcontext memory context.
+ */
+static void
+build_hash_table(Agg *node)
+{
+ AggState *aggstate = node->aggstate;
+ AggHashTable hashtable;
+ Size tabsize;
+
+ Assert(node->aggstrategy == AGG_HASHED);
+ Assert(node->numGroups > 0);
+ tabsize = sizeof(AggHashTableData) +
+ (node->numGroups - 1) * sizeof(AggHashEntry);
+ hashtable = (AggHashTable) MemoryContextAlloc(aggstate->aggcontext,
+ tabsize);
+ MemSet(hashtable, 0, tabsize);
+ hashtable->nbuckets = node->numGroups;
+ aggstate->hashtable = hashtable;
+}
+
+/*
+ * Find or create a hashtable entry for the tuple group containing the
+ * given tuple.
+ *
+ * When called, CurrentMemoryContext should be the per-query context.
+ */
+static AggHashEntry
+lookup_hash_entry(Agg *node, TupleTableSlot *slot)
+{
+ AggState *aggstate = node->aggstate;
+ AggHashTable hashtable = aggstate->hashtable;
+ MemoryContext tmpmem = aggstate->tmpcontext->ecxt_per_tuple_memory;
+ HeapTuple tuple = slot->val;
+ TupleDesc tupdesc = slot->ttc_tupleDescriptor;
+ uint32 hashkey = 0;
+ int i;
+ int bucketno;
+ AggHashEntry entry;
+ MemoryContext oldContext;
+ Size entrysize;
+
+ /* Need to run the hash function in short-lived context */
+ oldContext = MemoryContextSwitchTo(tmpmem);
+
+ for (i = 0; i < node->numCols; i++)
+ {
+ AttrNumber att = node->grpColIdx[i];
+ Datum attr;
+ bool isNull;
+
+ attr = heap_getattr(tuple, att, tupdesc, &isNull);
+ if (isNull)
+ continue; /* treat nulls as having hash key 0 */
+ hashkey ^= ComputeHashFunc(attr,
+ (int) tupdesc->attrs[att - 1]->attlen,
+ tupdesc->attrs[att - 1]->attbyval);
+ }
+ bucketno = hashkey % (uint32) hashtable->nbuckets;
+
+ for (entry = hashtable->buckets[bucketno];
+ entry != NULL;
+ entry = entry->next)
+ {
+ /* Quick check using hashkey */
+ if (entry->hashkey != hashkey)
+ continue;
+ if (execTuplesMatch(entry->firstTuple,
+ tuple,
+ tupdesc,
+ node->numCols, node->grpColIdx,
+ aggstate->eqfunctions,
+ tmpmem))
+ {
+ MemoryContextSwitchTo(oldContext);
+ return entry;
+ }
+ }
+
+ /* Not there, so build a new one */
+ MemoryContextSwitchTo(aggstate->aggcontext);
+ entrysize = sizeof(AggHashEntryData) +
+ (aggstate->numaggs - 1) * sizeof(AggStatePerGroupData);
+ entry = (AggHashEntry) palloc(entrysize);
+ MemSet(entry, 0, entrysize);
+
+ entry->hashkey = hashkey;
+ entry->firstTuple = heap_copytuple(tuple);
+
+ entry->next = hashtable->buckets[bucketno];
+ hashtable->buckets[bucketno] = entry;
+
+ MemoryContextSwitchTo(oldContext);
+
+ /* initialize aggregates for new tuple group */
+ initialize_aggregates(aggstate, aggstate->peragg, entry->pergroup);
+
+ return entry;
+}
/*
* ExecAgg -
*/
TupleTableSlot *
ExecAgg(Agg *node)
+{
+ AggState *aggstate = node->aggstate;
+
+ if (aggstate->agg_done)
+ return NULL;
+
+ if (node->aggstrategy == AGG_HASHED)
+ {
+ if (!aggstate->table_filled)
+ agg_fill_hash_table(node);
+ return agg_retrieve_hash_table(node);
+ }
+ else
+ {
+ return agg_retrieve_direct(node);
+ }
+}
+
+/*
+ * ExecAgg for non-hashed case
+ */
+static TupleTableSlot *
+agg_retrieve_direct(Agg *node)
{
AggState *aggstate;
- EState *estate;
Plan *outerPlan;
ExprContext *econtext;
+ ExprContext *tmpcontext;
ProjectionInfo *projInfo;
Datum *aggvalues;
bool *aggnulls;
AggStatePerAgg peragg;
- MemoryContext oldContext;
+ AggStatePerGroup pergroup;
TupleTableSlot *outerslot;
TupleTableSlot *firstSlot;
TupleTableSlot *resultSlot;
* get state info from node
*/
aggstate = node->aggstate;
- estate = node->plan.state;
outerPlan = outerPlan(node);
+ /* econtext is the per-output-tuple expression context */
econtext = aggstate->csstate.cstate.cs_ExprContext;
aggvalues = econtext->ecxt_aggvalues;
aggnulls = econtext->ecxt_aggnulls;
+ /* tmpcontext is the per-input-tuple expression context */
+ tmpcontext = aggstate->tmpcontext;
projInfo = aggstate->csstate.cstate.cs_ProjInfo;
peragg = aggstate->peragg;
+ pergroup = aggstate->pergroup;
firstSlot = aggstate->csstate.css_ScanTupleSlot;
/*
/*
* Clear the per-output-tuple context for each group
*/
- MemoryContextReset(aggstate->tup_cxt);
+ ResetExprContext(econtext);
/*
* Initialize working state for a new input tuple group
*/
- for (aggno = 0; aggno < aggstate->numaggs; aggno++)
- {
- AggStatePerAgg peraggstate = &peragg[aggno];
-
- initialize_aggregate(peraggstate);
- }
+ initialize_aggregates(aggstate, peragg, pergroup);
if (aggstate->grp_firstTuple != NULL)
{
aggstate->grp_firstTuple = NULL; /* don't keep two pointers */
/* set up for first advance_aggregates call */
- econtext->ecxt_scantuple = firstSlot;
+ tmpcontext->ecxt_scantuple = firstSlot;
/*
* Process each outer-plan tuple, and then fetch the next one,
*/
for (;;)
{
- advance_aggregates(aggstate, econtext);
+ advance_aggregates(aggstate, pergroup);
+
+ /* Reset per-input-tuple context after each tuple */
+ ResetExprContext(tmpcontext);
outerslot = ExecProcNode(outerPlan, (Plan *) node);
if (TupIsNull(outerslot))
break;
}
/* set up for next advance_aggregates call */
- econtext->ecxt_scantuple = outerslot;
+ tmpcontext->ecxt_scantuple = outerslot;
/*
* If we are grouping, check whether we've crossed a group
firstSlot->ttc_tupleDescriptor,
node->numCols, node->grpColIdx,
aggstate->eqfunctions,
- aggstate->agg_cxt[aggstate->which_cxt]))
+ tmpcontext->ecxt_per_tuple_memory))
{
/*
* Save the first input tuple of the next group.
/*
* Done scanning input tuple group. Finalize each aggregate
* calculation, and stash results in the per-output-tuple context.
- *
- * This is a bit tricky when there are both DISTINCT and plain
- * aggregates: we must first finalize all the plain aggs and then
- * all the DISTINCT ones. This is needed because the last
- * transition values for the plain aggs are stored in the
- * not-current working context, and we have to evaluate those aggs
- * (and stash the results in the output tup_cxt!) before we start
- * flipping contexts again in process_sorted_aggregate.
*/
- oldContext = MemoryContextSwitchTo(aggstate->tup_cxt);
- for (aggno = 0; aggno < aggstate->numaggs; aggno++)
- {
- AggStatePerAgg peraggstate = &peragg[aggno];
-
- if (!peraggstate->aggref->aggdistinct)
- finalize_aggregate(peraggstate,
- &aggvalues[aggno], &aggnulls[aggno]);
- }
- MemoryContextSwitchTo(oldContext);
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
{
AggStatePerAgg peraggstate = &peragg[aggno];
+ AggStatePerGroup pergroupstate = &pergroup[aggno];
if (peraggstate->aggref->aggdistinct)
- {
- process_sorted_aggregate(aggstate, peraggstate);
- oldContext = MemoryContextSwitchTo(aggstate->tup_cxt);
- finalize_aggregate(peraggstate,
- &aggvalues[aggno], &aggnulls[aggno]);
- MemoryContextSwitchTo(oldContext);
- }
+ process_sorted_aggregate(aggstate, peraggstate, pergroupstate);
+
+ finalize_aggregate(aggstate, peraggstate, pergroupstate,
+ &aggvalues[aggno], &aggnulls[aggno]);
}
/*
}
/*
- * Do projection and qual check in the per-output-tuple context.
+ * Form a projection tuple using the aggregate results and the
+ * representative input tuple. Store it in the result tuple slot.
+ * Note we do not support aggregates returning sets ...
+ */
+ econtext->ecxt_scantuple = firstSlot;
+ resultSlot = ExecProject(projInfo, NULL);
+
+ /*
+ * If the completed tuple does not match the qualifications, it is
+ * ignored and we loop back to try to process another group.
+ * Otherwise, return the tuple.
+ */
+ }
+ while (!ExecQual(node->plan.qual, econtext, false));
+
+ return resultSlot;
+}
+
+/*
+ * ExecAgg for hashed case: phase 1, read input and build hash table
+ */
+static void
+agg_fill_hash_table(Agg *node)
+{
+ AggState *aggstate;
+ Plan *outerPlan;
+ ExprContext *tmpcontext;
+ AggHashEntry entry;
+ TupleTableSlot *outerslot;
+
+ /*
+ * get state info from node
+ */
+ aggstate = node->aggstate;
+ outerPlan = outerPlan(node);
+ /* tmpcontext is the per-input-tuple expression context */
+ tmpcontext = aggstate->tmpcontext;
+
+ /*
+ * Process each outer-plan tuple, and then fetch the next one,
+ * until we exhaust the outer plan.
+ */
+ for (;;)
+ {
+ outerslot = ExecProcNode(outerPlan, (Plan *) node);
+ if (TupIsNull(outerslot))
+ break;
+ /* set up for advance_aggregates call */
+ tmpcontext->ecxt_scantuple = outerslot;
+
+ /* Find or build hashtable entry for this tuple's group */
+ entry = lookup_hash_entry(node, outerslot);
+
+ /* Advance the aggregates */
+ advance_aggregates(aggstate, entry->pergroup);
+
+ /* Reset per-input-tuple context after each tuple */
+ ResetExprContext(tmpcontext);
+ }
+
+ aggstate->table_filled = true;
+ /* Initialize to walk the hash table */
+ aggstate->next_hash_entry = NULL;
+ aggstate->next_hash_bucket = 0;
+}
+
+/*
+ * ExecAgg for hashed case: phase 2, retrieving groups from hash table
+ */
+static TupleTableSlot *
+agg_retrieve_hash_table(Agg *node)
+{
+ AggState *aggstate;
+ ExprContext *econtext;
+ ProjectionInfo *projInfo;
+ Datum *aggvalues;
+ bool *aggnulls;
+ AggStatePerAgg peragg;
+ AggStatePerGroup pergroup;
+ AggHashTable hashtable;
+ AggHashEntry entry;
+ TupleTableSlot *firstSlot;
+ TupleTableSlot *resultSlot;
+ int aggno;
+
+ /*
+ * get state info from node
+ */
+ aggstate = node->aggstate;
+ /* econtext is the per-output-tuple expression context */
+ econtext = aggstate->csstate.cstate.cs_ExprContext;
+ aggvalues = econtext->ecxt_aggvalues;
+ aggnulls = econtext->ecxt_aggnulls;
+ projInfo = aggstate->csstate.cstate.cs_ProjInfo;
+ peragg = aggstate->peragg;
+ hashtable = aggstate->hashtable;
+ firstSlot = aggstate->csstate.css_ScanTupleSlot;
+
+ /*
+ * We loop retrieving groups until we find one matching
+ * node->plan.qual
+ */
+ do
+ {
+ if (aggstate->agg_done)
+ return NULL;
+
+ /*
+ * Find the next entry in the hash table
+ */
+ entry = aggstate->next_hash_entry;
+ while (entry == NULL)
+ {
+ if (aggstate->next_hash_bucket >= hashtable->nbuckets)
+ {
+ /* No more entries in hashtable, so done */
+ aggstate->agg_done = TRUE;
+ return NULL;
+ }
+ entry = hashtable->buckets[aggstate->next_hash_bucket++];
+ }
+ aggstate->next_hash_entry = entry->next;
+
+ /*
+ * Clear the per-output-tuple context for each group
+ */
+ ResetExprContext(econtext);
+
+ /*
+ * Store the copied first input tuple in the tuple table slot
+ * reserved for it, so that it can be used in ExecProject.
*/
- econtext->ecxt_per_tuple_memory = aggstate->tup_cxt;
+ ExecStoreTuple(entry->firstTuple,
+ firstSlot,
+ InvalidBuffer,
+ false);
+
+ pergroup = entry->pergroup;
+
+ /*
+ * Finalize each aggregate calculation, and stash results in the
+ * per-output-tuple context.
+ */
+ for (aggno = 0; aggno < aggstate->numaggs; aggno++)
+ {
+ AggStatePerAgg peraggstate = &peragg[aggno];
+ AggStatePerGroup pergroupstate = &pergroup[aggno];
+
+ Assert(!peraggstate->aggref->aggdistinct);
+ finalize_aggregate(aggstate, peraggstate, pergroupstate,
+ &aggvalues[aggno], &aggnulls[aggno]);
+ }
/*
* Form a projection tuple using the aggregate results and the
aggstate = makeNode(AggState);
node->aggstate = aggstate;
aggstate->eqfunctions = NULL;
- aggstate->grp_firstTuple = NULL;
+ aggstate->peragg = NULL;
aggstate->agg_done = false;
+ aggstate->pergroup = NULL;
+ aggstate->grp_firstTuple = NULL;
+ aggstate->hashtable = NULL;
/*
* find aggregates in targetlist and quals
}
/*
- * Create expression context
+ * Create expression contexts. We need two, one for per-input-tuple
+ * processing and one for per-output-tuple processing. We cheat a little
+ * by using ExecAssignExprContext() to build both.
*/
ExecAssignExprContext(estate, &aggstate->csstate.cstate);
+ aggstate->tmpcontext = aggstate->csstate.cstate.cs_ExprContext;
+ ExecAssignExprContext(estate, &aggstate->csstate.cstate);
/*
- * We actually need three separate expression memory contexts: one for
- * calculating per-output-tuple values (ie, the finished aggregate
- * results), and two that we ping-pong between for per-input-tuple
- * evaluation of input expressions and transition functions. The
- * context made by ExecAssignExprContext() is used as the output
- * context.
+ * We also need a long-lived memory context for holding hashtable
+ * data structures and transition values. NOTE: the details of what
+ * is stored in aggcontext and what is stored in the regular per-query
+ * memory context are driven by a simple decision: we want to reset the
+ * aggcontext in ExecReScanAgg to recover no-longer-wanted space.
*/
- aggstate->tup_cxt =
- aggstate->csstate.cstate.cs_ExprContext->ecxt_per_tuple_memory;
- aggstate->agg_cxt[0] =
+ aggstate->aggcontext =
AllocSetContextCreate(CurrentMemoryContext,
- "AggExprContext1",
+ "AggContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
- aggstate->agg_cxt[1] =
- AllocSetContextCreate(CurrentMemoryContext,
- "AggExprContext2",
- ALLOCSET_DEFAULT_MINSIZE,
- ALLOCSET_DEFAULT_INITSIZE,
- ALLOCSET_DEFAULT_MAXSIZE);
- aggstate->which_cxt = 0;
#define AGG_NSLOTS 2
ExecInitResultTupleSlot(estate, &aggstate->csstate.cstate);
/*
- * Set up aggregate-result storage in the expr context, and also
+ * Set up aggregate-result storage in the output expr context, and also
* allocate my private per-agg working storage
*/
econtext = aggstate->csstate.cstate.cs_ExprContext;
MemSet(peragg, 0, sizeof(AggStatePerAggData) * numaggs);
aggstate->peragg = peragg;
+ if (node->aggstrategy == AGG_HASHED)
+ {
+ build_hash_table(node);
+ aggstate->table_filled = false;
+ }
+ else
+ {
+ AggStatePerGroup pergroup;
+
+ pergroup = (AggStatePerGroup) palloc(sizeof(AggStatePerGroupData) * numaggs);
+ MemSet(pergroup, 0, sizeof(AggStatePerGroupData) * numaggs);
+ aggstate->pergroup = pergroup;
+ }
+
/*
* initialize child nodes
*/
{
/*
* Note: use the type from the input expression here, not from
- * pg_proc.proargtypes, because the latter might be 0.
+ * pg_proc.proargtypes, because the latter might be a pseudotype.
* (Consider COUNT(*).)
*/
Oid inputType = exprType(aggref->target);
Oid eq_function;
+ /* We don't implement DISTINCT aggs in the HASHED case */
+ Assert(node->aggstrategy != AGG_HASHED);
+
peraggstate->inputType = inputType;
get_typlenbyval(inputType,
&peraggstate->inputtypeLen,
{
AggState *aggstate = node->aggstate;
Plan *outerPlan;
+ int aggno;
+
+ /* Make sure we have closed any open tuplesorts */
+ for (aggno = 0; aggno < aggstate->numaggs; aggno++)
+ {
+ AggStatePerAgg peraggstate = &aggstate->peragg[aggno];
+
+ if (peraggstate->sortstate)
+ tuplesort_end(peraggstate->sortstate);
+ }
ExecFreeProjectionInfo(&aggstate->csstate.cstate);
/*
- * Make sure ExecFreeExprContext() frees the right expr context...
+ * Free both the expr contexts.
*/
- aggstate->csstate.cstate.cs_ExprContext->ecxt_per_tuple_memory =
- aggstate->tup_cxt;
+ ExecFreeExprContext(&aggstate->csstate.cstate);
+ aggstate->csstate.cstate.cs_ExprContext = aggstate->tmpcontext;
ExecFreeExprContext(&aggstate->csstate.cstate);
- /*
- * ... and I free the others.
- */
- MemoryContextDelete(aggstate->agg_cxt[0]);
- MemoryContextDelete(aggstate->agg_cxt[1]);
+ MemoryContextDelete(aggstate->aggcontext);
outerPlan = outerPlan(node);
ExecEndNode(outerPlan, (Plan *) node);
{
AggState *aggstate = node->aggstate;
ExprContext *econtext = aggstate->csstate.cstate.cs_ExprContext;
+ int aggno;
+
+ /* Make sure we have closed any open tuplesorts */
+ for (aggno = 0; aggno < aggstate->numaggs; aggno++)
+ {
+ AggStatePerAgg peraggstate = &aggstate->peragg[aggno];
+
+ if (peraggstate->sortstate)
+ tuplesort_end(peraggstate->sortstate);
+ peraggstate->sortstate = NULL;
+ }
aggstate->agg_done = false;
if (aggstate->grp_firstTuple != NULL)
MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * aggstate->numaggs);
MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * aggstate->numaggs);
+ MemoryContextReset(aggstate->aggcontext);
+
+ if (node->aggstrategy == AGG_HASHED)
+ {
+ build_hash_table(node);
+ aggstate->table_filled = false;
+ }
+
/*
* if chgParam of subnode is not null then plan will be re-scanned by
* first ExecProcNode.
projects / postgresql.git / commitdiff