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Do execGrouping.c via expression eval machinery.
This has a performance benefit on own, although not hugely so. The primary benefit is that it will allow for to JIT tuple deforming and comparator invocations. Author: Andres Freund Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de
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15 files changed

+498
-366
lines changed

15 files changed

+498
-366
lines changed

‎src/backend/executor/execExpr.c

Lines changed: 118 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3193,3 +3193,121 @@ ExecBuildAggTransCall(ExprState *state, AggState *aggstate,
31933193
as->d.agg_strict_trans_check.jumpnull = state->steps_len;
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}
31953195
}
3196+
3197+
/*
3198+
* Build equality expression that can be evaluated using ExecQual(), returning
3199+
* true if the expression context's inner/outer tuple are NOT DISTINCT. I.e
3200+
* two nulls match, a null and a not-null don't match.
3201+
*
3202+
* desc: tuple descriptor of the to-be-compared tuples
3203+
* numCols: the number of attributes to be examined
3204+
* keyColIdx: array of attribute column numbers
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* eqFunctions: array of function oids of the equality functions to use
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* parent: parent executor node
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*/
3208+
ExprState *
3209+
ExecBuildGroupingEqual(TupleDesc desc,
3210+
int numCols,
3211+
AttrNumber *keyColIdx,
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Oid *eqfunctions,
3213+
PlanState *parent)
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{
3215+
ExprState *state = makeNode(ExprState);
3216+
ExprEvalStep scratch = {0};
3217+
int natt;
3218+
int maxatt = -1;
3219+
List *adjust_jumps = NIL;
3220+
ListCell *lc;
3221+
3222+
/*
3223+
* When no columns are actually compared, the result's always true. See
3224+
* special case in ExecQual().
3225+
*/
3226+
if (numCols == 0)
3227+
return NULL;
3228+
3229+
state->expr = NULL;
3230+
state->flags = EEO_FLAG_IS_QUAL;
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state->parent = parent;
3232+
3233+
scratch.resvalue = &state->resvalue;
3234+
scratch.resnull = &state->resnull;
3235+
3236+
/* compute max needed attribute */
3237+
for (natt = 0; natt < numCols; natt++)
3238+
{
3239+
int attno = keyColIdx[natt];
3240+
3241+
if (attno > maxatt)
3242+
maxatt = attno;
3243+
}
3244+
Assert(maxatt >= 0);
3245+
3246+
/* push deform steps */
3247+
scratch.opcode = EEOP_INNER_FETCHSOME;
3248+
scratch.d.fetch.last_var = maxatt;
3249+
ExprEvalPushStep(state, &scratch);
3250+
3251+
scratch.opcode = EEOP_OUTER_FETCHSOME;
3252+
scratch.d.fetch.last_var = maxatt;
3253+
ExprEvalPushStep(state, &scratch);
3254+
3255+
/*
3256+
* Start comparing at the last field (least significant sort key). That's
3257+
* the most likely to be different if we are dealing with sorted input.
3258+
*/
3259+
for (natt = numCols; --natt >= 0;)
3260+
{
3261+
int attno = keyColIdx[natt];
3262+
Form_pg_attribute att = TupleDescAttr(desc, attno - 1);
3263+
Var *larg,
3264+
*rarg;
3265+
List *args;
3266+
3267+
/*
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* Reusing ExecInitFunc() requires creating Vars, but still seems
3269+
* worth it from a code reuse perspective.
3270+
*/
3271+
3272+
/* left arg */
3273+
larg = makeVar(INNER_VAR, attno, att->atttypid,
3274+
att->atttypmod, InvalidOid, 0);
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/* right arg */
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rarg = makeVar(OUTER_VAR, attno, att->atttypid,
3277+
att->atttypmod, InvalidOid, 0);
3278+
args = list_make2(larg, rarg);
3279+
3280+
/* evaluate distinctness */
3281+
ExecInitFunc(&scratch, NULL,
3282+
args, eqfunctions[natt], InvalidOid,
3283+
state);
3284+
scratch.opcode = EEOP_NOT_DISTINCT;
3285+
ExprEvalPushStep(state, &scratch);
3286+
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/* then emit EEOP_QUAL to detect if result is false (or null) */
3288+
scratch.opcode = EEOP_QUAL;
3289+
scratch.d.qualexpr.jumpdone = -1;
3290+
ExprEvalPushStep(state, &scratch);
3291+
adjust_jumps = lappend_int(adjust_jumps,
3292+
state->steps_len - 1);
3293+
}
3294+
3295+
/* adjust jump targets */
3296+
foreach(lc, adjust_jumps)
3297+
{
3298+
ExprEvalStep *as = &state->steps[lfirst_int(lc)];
3299+
3300+
Assert(as->opcode == EEOP_QUAL);
3301+
Assert(as->d.qualexpr.jumpdone == -1);
3302+
as->d.qualexpr.jumpdone = state->steps_len;
3303+
}
3304+
3305+
scratch.resvalue = NULL;
3306+
scratch.resnull = NULL;
3307+
scratch.opcode = EEOP_DONE;
3308+
ExprEvalPushStep(state, &scratch);
3309+
3310+
ExecReadyExpr(state);
3311+
3312+
return state;
3313+
}

‎src/backend/executor/execExprInterp.c

Lines changed: 29 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -355,6 +355,7 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
355355
&&CASE_EEOP_MAKE_READONLY,
356356
&&CASE_EEOP_IOCOERCE,
357357
&&CASE_EEOP_DISTINCT,
358+
&&CASE_EEOP_NOT_DISTINCT,
358359
&&CASE_EEOP_NULLIF,
359360
&&CASE_EEOP_SQLVALUEFUNCTION,
360361
&&CASE_EEOP_CURRENTOFEXPR,
@@ -1198,6 +1199,34 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
11981199
EEO_NEXT();
11991200
}
12001201

1202+
/* see EEOP_DISTINCT for comments, this is just inverted */
1203+
EEO_CASE(EEOP_NOT_DISTINCT)
1204+
{
1205+
FunctionCallInfo fcinfo = op->d.func.fcinfo_data;
1206+
1207+
if (fcinfo->argnull[0] && fcinfo->argnull[1])
1208+
{
1209+
*op->resvalue = BoolGetDatum(true);
1210+
*op->resnull = false;
1211+
}
1212+
else if (fcinfo->argnull[0] || fcinfo->argnull[1])
1213+
{
1214+
*op->resvalue = BoolGetDatum(false);
1215+
*op->resnull = false;
1216+
}
1217+
else
1218+
{
1219+
Datum eqresult;
1220+
1221+
fcinfo->isnull = false;
1222+
eqresult = op->d.func.fn_addr(fcinfo);
1223+
*op->resvalue = eqresult;
1224+
*op->resnull = fcinfo->isnull;
1225+
}
1226+
1227+
EEO_NEXT();
1228+
}
1229+
12011230
EEO_CASE(EEOP_NULLIF)
12021231
{
12031232
/*

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