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Simplify executor's handling of CaseTestExpr & CoerceToDomainValue.

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Instead of deciding at runtime whether to read from casetest.value
or caseValue_datum, split EEOP_CASE_TESTVAL into two opcodes and
make the decision during expression compilation.  Similarly for
EEOP_DOMAIN_TESTVAL.  This actually results in net less code,
mainly because llvmjit_expr.c's code for handling these opcodes
gets shorter.  The performance gain is doubtless negligible, but
this seems worth changing anyway on grounds of simplicity and
understandability.

Author: Andreas Karlsson <andreas@proxel.se>
Co-authored-by: Xing Guo <higuoxing@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CACpMh+AiBYAWn+D1aU7Rsy-V1tox06Cbc0H3qA7rwL5zdJ=anQ@mail.gmail.com
This commit is contained in:
Tom Lane
2025-01-30 13:21:42 -05:00
parent 6252b1eaf8
commit 115a365519
4 changed files with 65 additions and 90 deletions
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34
src/backend/executor/execExpr.c
View File

@@ -1901,13 +1901,17 @@ ExecInitExprRec(Expr *node, ExprState *state,
* actually within a CaseExpr, ArrayCoerceExpr, etc structure.
* That can happen because some parts of the system abuse
* CaseTestExpr to cause a read of a value externally supplied
* in econtext->caseValue_datum. We'll take care of that
* scenario at runtime.
* in econtext->caseValue_datum. We'll take care of that by
* generating a specialized operation.
*/
scratch.opcode = EEOP_CASE_TESTVAL;
scratch.d.casetest.value = state->innermost_caseval;
scratch.d.casetest.isnull = state->innermost_casenull;
if (state->innermost_caseval == NULL)
scratch.opcode = EEOP_CASE_TESTVAL_EXT;
else
{
scratch.opcode = EEOP_CASE_TESTVAL;
scratch.d.casetest.value = state->innermost_caseval;
scratch.d.casetest.isnull = state->innermost_casenull;
}
ExprEvalPushStep(state, &scratch);
break;
}
@@ -2594,14 +2598,18 @@ ExecInitExprRec(Expr *node, ExprState *state,
* that innermost_domainval could be NULL, if we're compiling
* a standalone domain check rather than one embedded in a
* larger expression. In that case we must read from
* econtext->domainValue_datum. We'll take care of that
* scenario at runtime.
* econtext->domainValue_datum. We'll take care of that by
* generating a specialized operation.
*/
scratch.opcode = EEOP_DOMAIN_TESTVAL;
/* we share instruction union variant with case testval */
scratch.d.casetest.value = state->innermost_domainval;
scratch.d.casetest.isnull = state->innermost_domainnull;
if (state->innermost_domainval == NULL)
scratch.opcode = EEOP_DOMAIN_TESTVAL_EXT;
else
{
scratch.opcode = EEOP_DOMAIN_TESTVAL;
/* we share instruction union variant with case testval */
scratch.d.casetest.value = state->innermost_domainval;
scratch.d.casetest.isnull = state->innermost_domainnull;
}
ExprEvalPushStep(state, &scratch);
break;
}

59
src/backend/executor/execExprInterp.c
View File

@@ -365,8 +365,7 @@ ExecReadyInterpretedExpr(ExprState *state)
return;
}
else if (step0 == EEOP_CASE_TESTVAL &&
step1 == EEOP_FUNCEXPR_STRICT &&
state->steps[0].d.casetest.value)
step1 == EEOP_FUNCEXPR_STRICT)
{
state->evalfunc_private = ExecJustApplyFuncToCase;
return;
@@ -524,6 +523,7 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
&&CASE_EEOP_PARAM_CALLBACK,
&&CASE_EEOP_PARAM_SET,
&&CASE_EEOP_CASE_TESTVAL,
&&CASE_EEOP_CASE_TESTVAL_EXT,
&&CASE_EEOP_MAKE_READONLY,
&&CASE_EEOP_IOCOERCE,
&&CASE_EEOP_IOCOERCE_SAFE,
@@ -548,6 +548,7 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
&&CASE_EEOP_SBSREF_ASSIGN,
&&CASE_EEOP_SBSREF_FETCH,
&&CASE_EEOP_DOMAIN_TESTVAL,
&&CASE_EEOP_DOMAIN_TESTVAL_EXT,
&&CASE_EEOP_DOMAIN_NOTNULL,
&&CASE_EEOP_DOMAIN_CHECK,
&&CASE_EEOP_HASHDATUM_SET_INITVAL,
@@ -1273,44 +1274,16 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
EEO_CASE(EEOP_CASE_TESTVAL)
{
/*
* Normally upper parts of the expression tree have setup the
* values to be returned here, but some parts of the system
* currently misuse {caseValue,domainValue}_{datum,isNull} to set
* run-time data. So if no values have been set-up, use
* ExprContext's. This isn't pretty, but also not *that* ugly,
* and this is unlikely to be performance sensitive enough to
* worry about an extra branch.
*/
if (op->d.casetest.value)
{
*op->resvalue = *op->d.casetest.value;
*op->resnull = *op->d.casetest.isnull;
}
else
{
*op->resvalue = econtext->caseValue_datum;
*op->resnull = econtext->caseValue_isNull;
}
*op->resvalue = *op->d.casetest.value;
*op->resnull = *op->d.casetest.isnull;
EEO_NEXT();
}
EEO_CASE(EEOP_DOMAIN_TESTVAL)
EEO_CASE(EEOP_CASE_TESTVAL_EXT)
{
/*
* See EEOP_CASE_TESTVAL comment.
*/
if (op->d.casetest.value)
{
*op->resvalue = *op->d.casetest.value;
*op->resnull = *op->d.casetest.isnull;
}
else
{
*op->resvalue = econtext->domainValue_datum;
*op->resnull = econtext->domainValue_isNull;
}
*op->resvalue = econtext->caseValue_datum;
*op->resnull = econtext->caseValue_isNull;
EEO_NEXT();
}
@@ -1726,6 +1699,22 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
EEO_NEXT();
}
EEO_CASE(EEOP_DOMAIN_TESTVAL)
{
*op->resvalue = *op->d.casetest.value;
*op->resnull = *op->d.casetest.isnull;
EEO_NEXT();
}
EEO_CASE(EEOP_DOMAIN_TESTVAL_EXT)
{
*op->resvalue = econtext->domainValue_datum;
*op->resnull = econtext->domainValue_isNull;
EEO_NEXT();
}
EEO_CASE(EEOP_DOMAIN_NOTNULL)
{
/* too complex for an inline implementation */