From 66a9003e2e3ec05e9b62d6bfb6797fa35fb01d15 Mon Sep 17 00:00:00 2001 From: Amit Langote Date: Fri, 21 Jul 2023 19:28:31 +0900 Subject: [PATCH] Don't include CaseTestExpr in JsonValueExpr.formatted_expr MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A CaseTestExpr is currently being put into JsonValueExpr.formatted_expr as placeholder for the result of evaluating JsonValueExpr.raw_expr, which in turn is evaluated separately. Though, there's no need for this indirection if raw_expr itself can be embedded into formatted_expr and evaluated as part of evaluating the latter, especially as there is no special reason to evaluate it separately. So this commit makes it so. As a result, JsonValueExpr.raw_expr no longer needs to be evaluated in ExecInterpExpr(), eval_const_exprs_mutator() etc. and is now only used for displaying the original "unformatted" expression in ruleutils.c. Comments about and the code manipulating formatted_expr is updated to mention that it is now always set and is the expression that gives a JsonValueExpr its runtime value. While at it, this also removes the function makeCaseTestExpr(), because the code in makeJsonConstructorExpr() looks more readable without it IMO and isn't used by anyone else either. Finally, a note is added in the comment above CaseTestExpr's definition that JsonConstructorExpr is also using it. Backpatched to 16 from the development branch to keep the code in sync across branches. Reviewed-by: Álvaro Herrera Discussion: https://postgr.es/m/CA+HiwqE4XTdfb1nW=Ojoy_tQSRhYt-q_kb6i5d4xcKyrLC1Nbg@mail.gmail.com --- src/backend/executor/execExpr.c | 17 +-------- src/backend/nodes/makefuncs.c | 7 ++-- src/backend/nodes/nodeFuncs.c | 4 +- src/backend/optimizer/util/clauses.c | 23 +++-------- src/backend/parser/gram.y | 4 +- src/backend/parser/parse_expr.c | 57 ++++++++++++++++------------ src/include/nodes/makefuncs.h | 3 +- src/include/nodes/primnodes.h | 8 +++- 8 files changed, 56 insertions(+), 67 deletions(-) diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c index e6e616865c..bf3a08c5f0 100644 --- a/src/backend/executor/execExpr.c +++ b/src/backend/executor/execExpr.c @@ -2294,21 +2294,8 @@ ExecInitExprRec(Expr *node, ExprState *state, { JsonValueExpr *jve = (JsonValueExpr *) node; - ExecInitExprRec(jve->raw_expr, state, resv, resnull); - - if (jve->formatted_expr) - { - Datum *innermost_caseval = state->innermost_caseval; - bool *innermost_isnull = state->innermost_casenull; - - state->innermost_caseval = resv; - state->innermost_casenull = resnull; - - ExecInitExprRec(jve->formatted_expr, state, resv, resnull); - - state->innermost_caseval = innermost_caseval; - state->innermost_casenull = innermost_isnull; - } + Assert(jve->formatted_expr != NULL); + ExecInitExprRec(jve->formatted_expr, state, resv, resnull); break; } diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c index 39e1884cf4..0e7e6e46d9 100644 --- a/src/backend/nodes/makefuncs.c +++ b/src/backend/nodes/makefuncs.c @@ -848,12 +848,13 @@ makeJsonFormat(JsonFormatType type, JsonEncoding encoding, int location) * creates a JsonValueExpr node */ JsonValueExpr * -makeJsonValueExpr(Expr *expr, JsonFormat *format) +makeJsonValueExpr(Expr *raw_expr, Expr *formatted_expr, + JsonFormat *format) { JsonValueExpr *jve = makeNode(JsonValueExpr); - jve->raw_expr = expr; - jve->formatted_expr = NULL; + jve->raw_expr = raw_expr; + jve->formatted_expr = formatted_expr; jve->format = format; return jve; diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c index c41e6bb984..503d76aae0 100644 --- a/src/backend/nodes/nodeFuncs.c +++ b/src/backend/nodes/nodeFuncs.c @@ -225,9 +225,7 @@ exprType(const Node *expr) { const JsonValueExpr *jve = (const JsonValueExpr *) expr; - type = exprType((Node *) - (jve->formatted_expr ? jve->formatted_expr : - jve->raw_expr)); + type = exprType((Node *) jve->formatted_expr); } break; case T_JsonConstructorExpr: diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 7f453b04f8..da258968b8 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -2827,25 +2827,12 @@ eval_const_expressions_mutator(Node *node, case T_JsonValueExpr: { JsonValueExpr *jve = (JsonValueExpr *) node; - Node *raw; + Node *formatted; - raw = eval_const_expressions_mutator((Node *) jve->raw_expr, - context); - if (raw && IsA(raw, Const)) - { - Node *formatted; - Node *save_case_val = context->case_val; - - context->case_val = raw; - - formatted = eval_const_expressions_mutator((Node *) jve->formatted_expr, - context); - - context->case_val = save_case_val; - - if (formatted && IsA(formatted, Const)) - return formatted; - } + formatted = eval_const_expressions_mutator((Node *) jve->formatted_expr, + context); + if (formatted && IsA(formatted, Const)) + return formatted; break; } diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index edb6c00ece..c31b373358 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -16353,7 +16353,9 @@ opt_asymmetric: ASYMMETRIC json_value_expr: a_expr json_format_clause_opt { - $$ = (Node *) makeJsonValueExpr((Expr *) $1, castNode(JsonFormat, $2)); + /* formatted_expr will be set during parse-analysis. */ + $$ = (Node *) makeJsonValueExpr((Expr *) $1, NULL, + castNode(JsonFormat, $2)); } ; diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 286e85d726..c08c06373a 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -3202,24 +3202,13 @@ makeJsonByteaToTextConversion(Node *expr, JsonFormat *format, int location) return (Node *) fexpr; } -/* - * Make a CaseTestExpr node. - */ -static Node * -makeCaseTestExpr(Node *expr) -{ - CaseTestExpr *placeholder = makeNode(CaseTestExpr); - - placeholder->typeId = exprType(expr); - placeholder->typeMod = exprTypmod(expr); - placeholder->collation = exprCollation(expr); - - return (Node *) placeholder; -} - /* * Transform JSON value expression using specified input JSON format or * default format otherwise. + * + * Returned expression is either ve->raw_expr coerced to text (if needed) or + * a JsonValueExpr with formatted_expr set to the coerced copy of raw_expr + * if the specified format requires it. */ static Node * transformJsonValueExpr(ParseState *pstate, const char *constructName, @@ -3268,11 +3257,8 @@ transformJsonValueExpr(ParseState *pstate, const char *constructName, if (format != JS_FORMAT_DEFAULT) { Oid targettype = format == JS_FORMAT_JSONB ? JSONBOID : JSONOID; - Node *orig = makeCaseTestExpr(expr); Node *coerced; - expr = orig; - if (exprtype != BYTEAOID && typcategory != TYPCATEGORY_STRING) ereport(ERROR, errcode(ERRCODE_DATATYPE_MISMATCH), @@ -3310,7 +3296,7 @@ transformJsonValueExpr(ParseState *pstate, const char *constructName, coerced = (Node *) fexpr; } - if (coerced == orig) + if (coerced == expr) expr = rawexpr; else { @@ -3322,6 +3308,10 @@ transformJsonValueExpr(ParseState *pstate, const char *constructName, } } + /* If returning a JsonValueExpr, formatted_expr must have been set. */ + Assert(!IsA(expr, JsonValueExpr) || + ((JsonValueExpr *) expr)->formatted_expr != NULL); + return expr; } @@ -3537,8 +3527,22 @@ makeJsonConstructorExpr(ParseState *pstate, JsonConstructorType type, jsctor->absent_on_null = absent_on_null; jsctor->location = location; + /* + * Coerce to the RETURNING type and format, if needed. We abuse + * CaseTestExpr here as placeholder to pass the result of either + * evaluating 'fexpr' or whatever is produced by ExecEvalJsonConstructor() + * that is of type JSON or JSONB to the coercion function. + */ if (fexpr) - placeholder = makeCaseTestExpr((Node *) fexpr); + { + CaseTestExpr *cte = makeNode(CaseTestExpr); + + cte->typeId = exprType((Node *) fexpr); + cte->typeMod = exprTypmod((Node *) fexpr); + cte->collation = exprCollation((Node *) fexpr); + + placeholder = (Node *) cte; + } else { CaseTestExpr *cte = makeNode(CaseTestExpr); @@ -3635,7 +3639,12 @@ transformJsonArrayQueryConstructor(ParseState *pstate, makeString(pstrdup("a"))); colref->location = ctor->location; - agg->arg = makeJsonValueExpr((Expr *) colref, ctor->format); + /* + * No formatting necessary, so set formatted_expr to be the same as + * raw_expr. + */ + agg->arg = makeJsonValueExpr((Expr *) colref, (Expr *) colref, + ctor->format); agg->absent_on_null = ctor->absent_on_null; agg->constructor = makeNode(JsonAggConstructor); agg->constructor->agg_order = NIL; @@ -3900,13 +3909,11 @@ transformJsonParseArg(ParseState *pstate, Node *jsexpr, JsonFormat *format, { JsonValueExpr *jve; - expr = makeCaseTestExpr(raw_expr); + expr = raw_expr; expr = makeJsonByteaToTextConversion(expr, format, exprLocation(expr)); *exprtype = TEXTOID; - jve = makeJsonValueExpr((Expr *) raw_expr, format); - - jve->formatted_expr = (Expr *) expr; + jve = makeJsonValueExpr((Expr *) raw_expr, (Expr *) expr, format); expr = (Node *) jve; } else diff --git a/src/include/nodes/makefuncs.h b/src/include/nodes/makefuncs.h index 06d991b725..3180703005 100644 --- a/src/include/nodes/makefuncs.h +++ b/src/include/nodes/makefuncs.h @@ -110,7 +110,8 @@ extern VacuumRelation *makeVacuumRelation(RangeVar *relation, Oid oid, List *va_ extern JsonFormat *makeJsonFormat(JsonFormatType type, JsonEncoding encoding, int location); -extern JsonValueExpr *makeJsonValueExpr(Expr *expr, JsonFormat *format); +extern JsonValueExpr *makeJsonValueExpr(Expr *raw_expr, Expr *formatted_expr, + JsonFormat *format); extern Node *makeJsonKeyValue(Node *key, Node *value); extern Node *makeJsonIsPredicate(Node *expr, JsonFormat *format, JsonValueType item_type, bool unique_keys, diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h index 792a743f72..e1aadc39cf 100644 --- a/src/include/nodes/primnodes.h +++ b/src/include/nodes/primnodes.h @@ -1264,6 +1264,8 @@ typedef struct CaseWhen * see build_coercion_expression(). * * Nested FieldStore/SubscriptingRef assignment expressions in INSERT/UPDATE; * see transformAssignmentIndirection(). + * * Placeholder for intermediate results in some SQL/JSON expression nodes, + * such as JsonConstructorExpr. * * The uses in CaseExpr and ArrayCoerceExpr are safe only to the extent that * there is not any other CaseExpr or ArrayCoerceExpr between the value source @@ -1593,12 +1595,16 @@ typedef struct JsonReturning /* * JsonValueExpr - * representation of JSON value expression (expr [FORMAT JsonFormat]) + * + * The actual value is obtained by evaluating formatted_expr. raw_expr is + * only there for displaying the original user-written expression and is not + * evaluated by ExecInterpExpr() and eval_const_exprs_mutator(). */ typedef struct JsonValueExpr { NodeTag type; Expr *raw_expr; /* raw expression */ - Expr *formatted_expr; /* formatted expression or NULL */ + Expr *formatted_expr; /* formatted expression */ JsonFormat *format; /* FORMAT clause, if specified */ } JsonValueExpr;