Hi čt 12. 3. 2026 v 8:00 odesílatel Pavel Stehule <[email protected]> napsal:
> Hi > > čt 12. 3. 2026 v 5:30 odesílatel Tom Lane <[email protected]> napsal: > >> Peter Eisentraut <[email protected]> writes: >> > Maybe this could be written in such a way that it doesn't hardcode JSON >> > arrays specifically, but a type could have an iteration helper function >> > that would feed this feature? >> >> +1. ISTM that this feature would make sense for subscriptable types, >> so one way to shoehorn it into the system without a lot of new overhead >> could be to extend struct SubscriptRoutines to offer optional support >> function(s) for iterating through all the elements of a subscriptable >> object. >> > > attached patch do this - new interface has two methods: CreateForeachAIterator and iterate diff --git a/src/include/nodes/subscripting.h b/src/include/nodes/subscripting.h index 301f21dac2f..08bfe59ede4 100644 --- a/src/include/nodes/subscripting.h +++ b/src/include/nodes/subscripting.h @@ -154,6 +154,32 @@ typedef void (*SubscriptExecSetup) (const SubscriptingRef *sbsref, SubscriptingRefState *sbsrefstate, SubscriptExecSteps *methods); +typedef struct _ForeachAIterator ForeachAIterator; + +/* + * ForeachAIiterator is used by PLpgSQL FOREACH IN ARRAY statement. + * Input value should not be null, and inside CreateForeachAIterator + * routine must be copied to current (statement) context. "iterate" + * routine is called under short life memory context, that is resetted + * after any call. + */ +struct _ForeachAIterator +{ + bool (*iterate) (ForeachAIterator *self, + Datum *value, + bool *isnull, + Oid *typid, + int32 *typmod); + /* Private fields might appear beyond this point... */ +}; + +typedef ForeachAIterator * (*CreateForeachAIterator) (Datum value, + Oid typid, + int32 typmod, + int slice, + Oid target_typid, + int32 target_typmod); + /* Struct returned by the SQL-visible subscript handler function */ typedef struct SubscriptRoutines { @@ -163,6 +189,9 @@ typedef struct SubscriptRoutines bool fetch_leakproof; /* is fetch SubscriptingRef leakproof? */ bool store_leakproof; /* is assignment SubscriptingRef * leakproof? */ + + /* returns iterator used by PL/pgSQL FOREACH statement */ + CreateForeachAIterator create_foreach_a_iterator; } SubscriptRoutines; #endif /* SUBSCRIPTING_H */ Regards Pavel > > > Regards > > Pavel > > >> >> regards, tom lane >> >
From b7b6509381a7d6b4629b3b25ebb4a189b1eb34be Mon Sep 17 00:00:00 2001 From: "[email protected]" <[email protected]> Date: Mon, 23 Feb 2026 12:53:44 +0100 Subject: [PATCH] FOREACH scalar IN ARRAY jsonb_expr this patch introduce support FOREACH scalar_var IN ARRAY expr, when the result of the expression can be Jsonb. The design is based on behave of jsonb_array_elements functions. In this case, FOREACH enforce casting to target type (because we know target type) and try to reduce IO casting. Attention: IO casting can be more strict, then casting based on cast functions. DECLARE t int; BEGIN -- this can work because we use cast numeric -> int FOREACH t IN ARRAY '[1,2,3.14]'::jsonb LOOP -- this fails, because IO cast is used, and integer input function -- allows only digits FOREAC t IN JSON ARRAY '[1,2,3,"3.14"]'::jsonb LOOP Conceptual question is if casting should be strict like "old" PostgreSQL json function or lax as "new" SQL/JSON functions? I can imagine lax mode as default with possibility to switch to strict mode (this is not implemented now): FOREACH t IN ARRAY '[1,2,3]' ERROR ON EMPTY ERROR ON ERROR LOOP ... Because we use "old" syntax - FOREACH IN ARRAY, I prefer "old" behaviour, that is more similar to iteration over an array. The performance (best case for iteration over 1000 fields array) is about 4x better than when FOR IN SELECT jsonb_array_elements is used. --- doc/src/sgml/plpgsql.sgml | 62 +++- src/backend/utils/adt/arraysubs.c | 97 +++++- src/backend/utils/adt/jsonbsubs.c | 181 ++++++++++- src/include/nodes/subscripting.h | 29 ++ src/pl/plpgsql/src/Makefile | 2 +- .../plpgsql/src/expected/plpgsql_foreach.out | 297 ++++++++++++++++++ src/pl/plpgsql/src/meson.build | 1 + src/pl/plpgsql/src/pl_exec.c | 189 +++++------ src/pl/plpgsql/src/plpgsql.h | 3 +- src/pl/plpgsql/src/sql/plpgsql_foreach.sql | 252 +++++++++++++++ 10 files changed, 1016 insertions(+), 97 deletions(-) create mode 100644 src/pl/plpgsql/src/expected/plpgsql_foreach.out create mode 100644 src/pl/plpgsql/src/sql/plpgsql_foreach.sql diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 561f6e50d63..6bc9fb02e1e 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -2697,12 +2697,12 @@ END LOOP <optional> <replaceable>label</replaceable> </optional>; </sect2> <sect2 id="plpgsql-foreach-array"> - <title>Looping through Arrays</title> + <title>Looping through Arrays or Jsonb arrays</title> <para> The <literal>FOREACH</literal> loop is much like a <literal>FOR</literal> loop, but instead of iterating through the rows returned by an SQL query, - it iterates through the elements of an array value. + it iterates through the elements of an array value or of jsonb array value. (In general, <literal>FOREACH</literal> is meant for looping through components of a composite-valued expression; variants for looping through composites besides arrays may be added in future.) @@ -2778,6 +2778,64 @@ NOTICE: row = {7,8,9} NOTICE: row = {10,11,12} </programlisting> </para> + + <para> + The <literal>SLICE</literal> higher than zero cannot be used when iterates + through jsonb arrays. + </para> + + <para> + The <literal>FOREACH</literal> loop over jsonb arrays uses + same syntax like <literal>FOREACH</literal> loop over arrays, + but instead of iterating through elements of the array, + it iterates through the elements of a Jsonb array value. + </para> + + <para> + The target can be a scalar variable, a composite variable, or a list + of scalar variables. When variable is not scalar, then assigned value + should be a JSON object and the JSON attributes are assigned by names. + +<programlisting> +CREATE FUNCTION print_elements(jsonb) RETURNS void AS $$ +DECLARE + x int; +BEGIN + FOREACH x IN ARRAY $1 + LOOP + RAISE NOTICE 'row = %', x; + END LOOP; +END; +$$ LANGUAGE plpgsql; + +SELECT print_elements('[1,2,3]'); +NOTICE: row = 1 +NOTICE: row = 2 +NOTICE: row = 3 + +CREATE FUNCTION print_fields(jsonb) RETURNS void AS $$ +DECLARE + x int; y varchar; +BEGIN + FOREACH x, y IN ARRAY $1 + LOOP + RAISE NOTICE 'x: %, y: %', x, y; + END LOOP; +END; +$$ LANGUAGE plpgsql; + +SELECT print_fields('[{},{"x":10},{"y":"Hi"},{"y":"Hi", "x":1000}]'); +NOTICE: x: <NULL>, y: <NULL> +NOTICE: x: 10, y: <NULL> +NOTICE: x: <NULL>, y: Hi +NOTICE: x: 1000, y: Hi +</programlisting> + </para> + + <para> + The target variable can be of type <literal>RECORD</literal>, but the real structure has to be + assigned before usage in the <literal>FOREACH</literal> statement. + </para> </sect2> <sect2 id="plpgsql-error-trapping"> diff --git a/src/backend/utils/adt/arraysubs.c b/src/backend/utils/adt/arraysubs.c index 2bf9e9509fb..a42248ed633 100644 --- a/src/backend/utils/adt/arraysubs.c +++ b/src/backend/utils/adt/arraysubs.c @@ -23,6 +23,7 @@ #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "utils/array.h" +#include "utils/builtins.h" #include "utils/fmgrprotos.h" #include "utils/lsyscache.h" @@ -46,6 +47,96 @@ typedef struct ArraySubWorkspace int lowerindex[MAXDIM]; } ArraySubWorkspace; +typedef struct +{ + ForeachAIterator pub; + ArrayIterator it; + Oid result_typid; + int32 result_typmod; +} ForeachAArrayIterState; + +static bool +foreach_a_array_iterate(ForeachAIterator *self, + Datum *value, bool *isnull, + Oid *typid, int32 *typmod) +{ + ForeachAArrayIterState *iter = (ForeachAArrayIterState *) self; + + *typid = iter->result_typid; + *typmod = iter->result_typmod; + + return array_iterate(iter->it, value, isnull); +} + +/* + * Used by plpgsql FOREACH IN ARRAY when input expression is an array + */ +static ForeachAIterator * +create_foreach_a_array_iterator(Datum value, Oid typid, int32 typmod, + int slice, Oid target_typid, int32 target_typmod) +{ + ForeachAArrayIterState *iter = palloc0(sizeof(ForeachAArrayIterState)); + ArrayType *arr; + Oid target_elem_typid; + + /* check the type of the expression - must be an array */ + if (!OidIsValid(get_element_type(typid))) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("FOREACH expression must yield an array, not type %s", + format_type_be(typid)))); + + /* + * We must copy the array into current context, because input expression + * is evaluated in context cleaned by exec_eval_cleanup. + */ + arr = DatumGetArrayTypePCopy(value); + + /* Slice dimension must be less than or equal to array dimension */ + if (slice < 0 || slice > ARR_NDIM(arr)) + ereport(ERROR, + (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR), + errmsg("slice dimension (%d) is out of the valid range 0..%d", + slice, ARR_NDIM(arr)))); + + /* + * Sanity-check the target type. We don't try very hard here, and + * should not be too picky since it's possible that exec_assign_value can + * coerce values of different types. But it seems worthwhile to complain + * if the array-ness of the loop variable is not right. + */ + target_elem_typid = get_element_type(target_typid); + + if (slice > 0 && target_elem_typid == InvalidOid) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("FOREACH ... SLICE loop variable must be of an array type"))); + if (slice == 0 && target_elem_typid != InvalidOid) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("FOREACH loop variable must not be of an array type"))); + + /* Identify iterator result type */ + if (slice > 0) + { + /* When slicing, nominal type of result is same as array type */ + iter->result_typid = typid; + iter->result_typmod = typmod; + } + else + { + /* Without slicing, results are individual array elements */ + iter->result_typid = ARR_ELEMTYPE(arr); + iter->result_typmod = typmod; + } + + /* Create an iterator to step through the array */ + iter->it = array_create_iterator(arr, slice, NULL); + + iter->pub.iterate = foreach_a_array_iterate; + + return (ForeachAIterator *) iter; +} /* * Finish parse analysis of a SubscriptingRef expression for an array. @@ -545,7 +636,8 @@ array_subscript_handler(PG_FUNCTION_ARGS) .exec_setup = array_exec_setup, .fetch_strict = true, /* fetch returns NULL for NULL inputs */ .fetch_leakproof = true, /* fetch returns NULL for bad subscript */ - .store_leakproof = false /* ... but assignment throws error */ + .store_leakproof = false, /* ... but assignment throws error */ + .create_foreach_a_iterator = create_foreach_a_array_iterator }; PG_RETURN_POINTER(&sbsroutines); @@ -572,7 +664,8 @@ raw_array_subscript_handler(PG_FUNCTION_ARGS) .exec_setup = array_exec_setup, .fetch_strict = true, /* fetch returns NULL for NULL inputs */ .fetch_leakproof = true, /* fetch returns NULL for bad subscript */ - .store_leakproof = false /* ... but assignment throws error */ + .store_leakproof = false, /* ... but assignment throws error */ + .create_foreach_a_iterator = create_foreach_a_array_iterator }; PG_RETURN_POINTER(&sbsroutines); diff --git a/src/backend/utils/adt/jsonbsubs.c b/src/backend/utils/adt/jsonbsubs.c index f2745b29a3f..ad2edf525de 100644 --- a/src/backend/utils/adt/jsonbsubs.c +++ b/src/backend/utils/adt/jsonbsubs.c @@ -22,6 +22,7 @@ #include "parser/parse_expr.h" #include "utils/builtins.h" #include "utils/jsonb.h" +#include "utils/jsonfuncs.h" /* SubscriptingRefState.workspace for jsonb subscripting execution */ @@ -33,6 +34,17 @@ typedef struct JsonbSubWorkspace Datum *index; /* Subscript values in Datum format */ } JsonbSubWorkspace; +typedef struct +{ + ForeachAIterator pub; + JsonbIterator *it; + bool skip_nested; + Oid target_typid; + int32 target_typmod; + + MemoryContext cache_mcxt; + void *cache; +} ForeachAJsonbIterState; /* * Finish parse analysis of a SubscriptingRef expression for a jsonb. @@ -394,6 +406,172 @@ jsonb_exec_setup(const SubscriptingRef *sbsref, methods->sbs_fetch_old = jsonb_subscript_fetch_old; } +/* + * Convert JsonbValue to Datum. This function is used in + * generic array iterator, that is used by FOREACH plpgsql + * statement. Against other cases, the result should not be + * necessary of expected_typid, because the value can be + * converted later when the value is assigned to PL/pgSQL + * variable. This can be more effective than generic IO + * cast used by json_populate_type. + */ +static Datum +JsonbValueToDatum(JsonbValue *jbv, + Oid *typid, int32 *typmod, bool *isnull, + Oid expected_typid, int32 expected_typmod, + void **cache, MemoryContext mcxt) +{ + Datum result; + + *isnull = false; + *typmod = -1; + + /* + * These types can holds JSON null, so must be processed + * before processing jbvNull. We don't want to convert + * JSON null, to SQL null, when targer is of JSON. + */ + if (expected_typid == JSONBOID || expected_typid == JSONOID) + { + Jsonb *jb = JsonbValueToJsonb(jbv); + + if (expected_typid == JSONOID) + { + char *str; + + str = JsonbToCString(NULL, &jb->root, VARSIZE(jb)); + result = PointerGetDatum(cstring_to_text(str)); + } + else + result = PointerGetDatum(jb); + + *typid = expected_typid; + } + + /* + * For special cases we can skip conversion to Jsonb + * and possibly IO cast. + */ + else if (jbv->type == jbvNull) + { + result = (Datum) 0; + *isnull = true; + *typid = expected_typid; + } + else if (jbv->type == jbvString) + { + text *txt = cstring_to_text_with_len(jbv->val.string.val, + jbv->val.string.len); + + result = PointerGetDatum(txt); + *typid = TEXTOID; + } + else if (jbv->type == jbvNumeric) + { + result = PointerGetDatum(jbv->val.numeric); + *typid = NUMERICOID; + } + else if (jbv->type == jbvBool) + { + result = BoolGetDatum(jbv->val.boolean); + *typid = BOOLOID; + } + + /* generic conversion */ + else + { + Jsonb *jb = JsonbValueToJsonb(jbv); + + result = json_populate_type(PointerGetDatum(jb), JSONBOID, + expected_typid, expected_typmod, + cache, mcxt, + isnull, false, NULL); + + *typid = expected_typid; + *typmod = expected_typmod; + } + + return result; +} + +static bool +foreach_a_jsonb_iterate(ForeachAIterator *self, + Datum *value, bool *isnull, + Oid *typid, int32 *typmod) +{ + ForeachAJsonbIterState *iter = (ForeachAJsonbIterState *) self; + JsonbIteratorToken r; + JsonbValue jbv; + + while ((r = JsonbIteratorNext(&iter->it, &jbv, iter->skip_nested)) != WJB_DONE) + { + iter->skip_nested = true; + + if (r == WJB_ELEM) + { + *value = JsonbValueToDatum(&jbv, typid, typmod, isnull, + iter->target_typid, iter->target_typmod, + &iter->cache, iter->cache_mcxt); + + return true; + } + } + + return false; +} + +/* + * Create foreach array iterator for jsonb array + */ +static ForeachAIterator * +create_foreach_a_jsonb_iterator(Datum value, Oid typid, int32 typmod, + int slice, Oid target_typid, int32 target_typmod) +{ + ForeachAJsonbIterState *iter = palloc0(sizeof(ForeachAJsonbIterState)); + Jsonb *jb; + + if (typid != JSONBOID) + elog(ERROR, "unexpected source type"); + + if (slice > 0) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("jsonb array iterator doesn't support slicing"))); + + /* + * We must copy the JSON into current context, because input expression + * is evaluated in context cleaned by exec_eval_cleanup. + */ + jb = DatumGetJsonbPCopy(value); + + /* + * Jsonb iterator is designed like jsonb_array_element. Input value + * must be json array. + */ + if (JB_ROOT_IS_SCALAR(jb)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("FOREACH expression must evaluate to a JSON array"), + errhint("Cannot iterate over a scalar value."))); + else if (JB_ROOT_IS_OBJECT(jb)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("FOREACH expression must evaluate to a JSON array"), + errdetail("Cannot iterate over an object value."))); + + Assert(JB_ROOT_IS_ARRAY(jb)); + + iter->it = JsonbIteratorInit(&jb->root); + + iter->target_typid = target_typid; + iter->target_typmod = target_typmod; + iter->cache_mcxt = CurrentMemoryContext; + + iter->pub.iterate = foreach_a_jsonb_iterate; + + return (ForeachAIterator *) iter; +} + /* * jsonb_subscript_handler * Subscripting handler for jsonb. @@ -407,7 +585,8 @@ jsonb_subscript_handler(PG_FUNCTION_ARGS) .exec_setup = jsonb_exec_setup, .fetch_strict = true, /* fetch returns NULL for NULL inputs */ .fetch_leakproof = true, /* fetch returns NULL for bad subscript */ - .store_leakproof = false /* ... but assignment throws error */ + .store_leakproof = false, /* ... but assignment throws error */ + .create_foreach_a_iterator = create_foreach_a_jsonb_iterator }; PG_RETURN_POINTER(&sbsroutines); diff --git a/src/include/nodes/subscripting.h b/src/include/nodes/subscripting.h index 301f21dac2f..08bfe59ede4 100644 --- a/src/include/nodes/subscripting.h +++ b/src/include/nodes/subscripting.h @@ -154,6 +154,32 @@ typedef void (*SubscriptExecSetup) (const SubscriptingRef *sbsref, SubscriptingRefState *sbsrefstate, SubscriptExecSteps *methods); +typedef struct _ForeachAIterator ForeachAIterator; + +/* + * ForeachAIiterator is used by PLpgSQL FOREACH IN ARRAY statement. + * Input value should not be null, and inside CreateForeachAIterator + * routine must be copied to current (statement) context. "iterate" + * routine is called under short life memory context, that is resetted + * after any call. + */ +struct _ForeachAIterator +{ + bool (*iterate) (ForeachAIterator *self, + Datum *value, + bool *isnull, + Oid *typid, + int32 *typmod); + /* Private fields might appear beyond this point... */ +}; + +typedef ForeachAIterator * (*CreateForeachAIterator) (Datum value, + Oid typid, + int32 typmod, + int slice, + Oid target_typid, + int32 target_typmod); + /* Struct returned by the SQL-visible subscript handler function */ typedef struct SubscriptRoutines { @@ -163,6 +189,9 @@ typedef struct SubscriptRoutines bool fetch_leakproof; /* is fetch SubscriptingRef leakproof? */ bool store_leakproof; /* is assignment SubscriptingRef * leakproof? */ + + /* returns iterator used by PL/pgSQL FOREACH statement */ + CreateForeachAIterator create_foreach_a_iterator; } SubscriptRoutines; #endif /* SUBSCRIPTING_H */ diff --git a/src/pl/plpgsql/src/Makefile b/src/pl/plpgsql/src/Makefile index 63cb96fae3e..5bd0cf31dfc 100644 --- a/src/pl/plpgsql/src/Makefile +++ b/src/pl/plpgsql/src/Makefile @@ -35,7 +35,7 @@ REGRESS_OPTS = --dbname=$(PL_TESTDB) REGRESS = plpgsql_array plpgsql_cache plpgsql_call plpgsql_control \ plpgsql_copy plpgsql_domain plpgsql_misc \ plpgsql_record plpgsql_simple plpgsql_transaction \ - plpgsql_trap plpgsql_trigger plpgsql_varprops + plpgsql_trap plpgsql_trigger plpgsql_varprops plpgsql_foreach # where to find gen_keywordlist.pl and subsidiary files TOOLSDIR = $(top_srcdir)/src/tools diff --git a/src/pl/plpgsql/src/expected/plpgsql_foreach.out b/src/pl/plpgsql/src/expected/plpgsql_foreach.out new file mode 100644 index 00000000000..ddc571f3c79 --- /dev/null +++ b/src/pl/plpgsql/src/expected/plpgsql_foreach.out @@ -0,0 +1,297 @@ +-- input must be a JSON array +do $$ +declare x numeric; +begin + foreach x in array NULL::jsonb -- fail + loop + raise notice '%', x; + end loop; +end; +$$; +ERROR: FOREACH expression must not be null +CONTEXT: PL/pgSQL function inline_code_block line 4 at FOREACH over array +do $$ +declare x numeric; +begin + foreach x in array jsonb '10' -- fail + loop + raise notice '%', x; + end loop; +end; +$$; +ERROR: FOREACH expression must evaluate to a JSON array +HINT: Cannot iterate over a scalar value. +CONTEXT: PL/pgSQL function inline_code_block line 4 at FOREACH over array +do $$ +declare x numeric; +begin + foreach x in array jsonb '{}' -- fail + loop + raise notice '%', x; + end loop; +end; +$$; +ERROR: FOREACH expression must evaluate to a JSON array +DETAIL: Cannot iterate over an object value. +CONTEXT: PL/pgSQL function inline_code_block line 4 at FOREACH over array +-- numeric to numeric +do $$ +declare x numeric; +begin + foreach x in array jsonb '[10,20,30,3.14, null]' + loop + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 10 +NOTICE: 20 +NOTICE: 30 +NOTICE: 3.14 +NOTICE: <NULL> +-- numeric to int by cast +do $$ +declare x int; +begin + foreach x in array jsonb '[10,20,30,3.14, null]' + loop + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 10 +NOTICE: 20 +NOTICE: 30 +NOTICE: 3 +NOTICE: <NULL> +-- test of FOUND variable +do $$ +declare x int; +begin + foreach x in array jsonb '[10]' + loop + raise notice '%', x; + end loop; + raise notice 'FOUND: %', found; +end; +$$; +NOTICE: 10 +NOTICE: FOUND: t +-- test of FOUND variable +do $$ +declare x int; +begin + foreach x in array jsonb '[]' + loop + raise notice '%', x; + end loop; + raise notice 'FOUND: %', found; +end; +$$; +NOTICE: FOUND: f +-- conversion "3.14" to int should to fail due IO cast +do $$ +declare x int; +begin + foreach x in array jsonb '["10",20,30,"3.14"]' + loop + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 10 +NOTICE: 20 +NOTICE: 30 +ERROR: invalid input syntax for type integer: "3.14" +CONTEXT: PL/pgSQL function inline_code_block line 4 at FOREACH over array +do $$ +declare x boolean; +begin + foreach x in array jsonb '[true, false]' + loop + if x then + raise notice 'true'; + else + raise notice 'false'; + end if; + end loop; +end; +$$; +NOTICE: true +NOTICE: false +-- jsonb to jsonb +do $$ +declare x jsonb; +begin + foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]' + loop + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 10 +NOTICE: 20 +NOTICE: 30 +NOTICE: 3.14 +NOTICE: null +NOTICE: "Hi" +-- jsonb to json +do $$ +declare x json; +begin + foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]' + loop + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 10 +NOTICE: 20 +NOTICE: 30 +NOTICE: 3.14 +NOTICE: null +NOTICE: "Hi" +-- iteration over composites +do $$ +declare x int; y numeric; z varchar; +begin + foreach x, y, z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]' + loop + raise notice 'x: %, y: %, z: %', x, y, z; + end loop; +end; +$$; +NOTICE: x: <NULL>, y: <NULL>, z: <NULL> +NOTICE: x: <NULL>, y: <NULL>, z: Hi +NOTICE: x: <NULL>, y: 3.14, z: <NULL> +NOTICE: x: 10, y: 3.14, z: Hi +create type t3 as (x int, y numeric, z varchar); +do $$ +declare c t3; +begin + foreach c in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]' + loop + raise notice 'x: %, y: %, z: %', c.x, c.y, c.z; + end loop; +end; +$$; +NOTICE: x: <NULL>, y: <NULL>, z: <NULL> +NOTICE: x: <NULL>, y: <NULL>, z: Hi +NOTICE: x: <NULL>, y: 3.14, z: <NULL> +NOTICE: x: 10, y: 3.14, z: Hi +do $$ +declare c t3; +begin + foreach c.x, c.y, c.z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]' + loop + raise notice 'x: %, y: %, z: %', c.x, c.y, c.z; + end loop; +end; +$$; +NOTICE: x: <NULL>, y: <NULL>, z: <NULL> +NOTICE: x: <NULL>, y: <NULL>, z: Hi +NOTICE: x: <NULL>, y: 3.14, z: <NULL> +NOTICE: x: 10, y: 3.14, z: Hi +drop type t3; +-- target can be a array +do $$ +declare x int[]; +begin + foreach x in array jsonb '[[1,2,3],[4,5,6]]' + loop + raise notice '% % %', x[1], x[2], x[3]; + end loop; +end; +$$; +NOTICE: 1 2 3 +NOTICE: 4 5 6 +do $$ +declare x varchar[]; +begin + foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]' + loop + raise notice '% %', x[1], x[2]; + end loop; +end; +$$; +NOTICE: Hi Hello +NOTICE: Hello Hi +do $$ +declare x varchar[]; +begin + foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]' + loop + raise notice '% %', x[1], x[2]; + end loop; +end; +$$; +NOTICE: Hi Hello +NOTICE: Hello Hi +do $$ +declare x int[]; y varchar; +begin + foreach x, y in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]' + loop + raise notice '% % %, y: %', x[1], x[2], x[3], y; + end loop; +end; +$$; +NOTICE: 1 2 3, y: Hi +NOTICE: 4 5 6, y: Hi +create type t2 as (x int[], y varchar); +do $$ +declare c t2; +begin + foreach c in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]' + loop + raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y; + end loop; +end; +$$; +NOTICE: 1 2 3, y: Hi +NOTICE: 4 5 6, y: Hi +drop type t2; +-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING +do $$ +declare x int; +begin + foreach x in array jsonb '[1,2,3,4,5]' + loop + exit when x = 3; + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 1 +NOTICE: 2 +do $$ +declare x int; +begin + foreach x in array jsonb '[1,2,3,4,5]' + loop + continue when x % 2 = 0; + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 1 +NOTICE: 3 +NOTICE: 5 +-- Variable instead of string +DO $$ +declare + x int; + arr jsonb; +begin + select jsonb_agg(i) into arr + from generate_series(1,3) g(i); + + foreach x in array arr + loop + raise notice '%', x; + end loop; +end; +$$; +NOTICE: 1 +NOTICE: 2 +NOTICE: 3 diff --git a/src/pl/plpgsql/src/meson.build b/src/pl/plpgsql/src/meson.build index 6ff27006cfc..609eed7a28d 100644 --- a/src/pl/plpgsql/src/meson.build +++ b/src/pl/plpgsql/src/meson.build @@ -88,6 +88,7 @@ tests += { 'plpgsql_trap', 'plpgsql_trigger', 'plpgsql_varprops', + 'plpgsql_foreach', ], }, } diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c index 84552e32c87..331d64119c1 100644 --- a/src/pl/plpgsql/src/pl_exec.c +++ b/src/pl/plpgsql/src/pl_exec.c @@ -29,6 +29,7 @@ #include "mb/stringinfo_mb.h" #include "miscadmin.h" #include "nodes/nodeFuncs.h" +#include "nodes/subscripting.h" #include "nodes/supportnodes.h" #include "optimizer/optimizer.h" #include "parser/parse_coerce.h" @@ -2994,40 +2995,49 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt) return rc; } - /* ---------- - * exec_stmt_foreach_a Loop over elements or slices of an array - * - * When looping over elements, the loop variable is the same type that the - * array stores (eg: integer), when looping through slices, the loop variable - * is an array of size and dimensions to match the size of the slice. - * ---------- + * exec_stmt_foreach_a Loop over elements in an array or jsonb array + * ---------- */ static int exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt) { - ArrayType *arr; - Oid arrtype; - int32 arrtypmod; - PLpgSQL_datum *loop_var; - Oid loop_var_elem_type; - bool found = false; + Datum expr; + Oid expr_typid; + int32 expr_typmod; + bool isnull; + PLpgSQL_datum *target_var; + Oid target_typid; + int32 target_typmod; + Oid target_collation; + Datum value; + Oid typid; + int32 typmod; int rc = PLPGSQL_RC_OK; + const struct SubscriptRoutines *sbroutines; + ForeachAIterator *iterator; MemoryContext stmt_mcontext; + MemoryContext tmp_cxt; MemoryContext oldcontext; - ArrayIterator array_iterator; - Oid iterator_result_type; - int32 iterator_result_typmod; - Datum value; - bool isnull; + bool found = false; - /* get the value of the array expression */ - value = exec_eval_expr(estate, stmt->expr, &isnull, &arrtype, &arrtypmod); + /* get the value of the expression */ + expr = exec_eval_expr(estate, stmt->expr, &isnull, + &expr_typid, &expr_typmod); if (isnull) ereport(ERROR, (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), errmsg("FOREACH expression must not be null"))); + sbroutines = getSubscriptingRoutines(expr_typid, NULL); + if (!sbroutines) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("cannot iterate over type %s because it does not support subscripting", + format_type_be(expr_typid)))); + + Assert(sbroutines->create_foreach_a_iterator); + /* * Do as much as possible of the code below in stmt_mcontext, to avoid any * leaks from called subroutines. We need a private stmt_mcontext since @@ -3037,79 +3047,34 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt) push_stmt_mcontext(estate); oldcontext = MemoryContextSwitchTo(stmt_mcontext); - /* check the type of the expression - must be an array */ - if (!OidIsValid(get_element_type(arrtype))) - ereport(ERROR, - (errcode(ERRCODE_DATATYPE_MISMATCH), - errmsg("FOREACH expression must yield an array, not type %s", - format_type_be(arrtype)))); + /* Set up the target (loop) variable */ + target_var = estate->datums[stmt->varno]; + + plpgsql_exec_get_datum_type_info(estate, target_var, + &target_typid, &target_typmod, + &target_collation); /* - * We must copy the array into stmt_mcontext, else it will disappear in - * exec_eval_cleanup. This is annoying, but cleanup will certainly happen - * while running the loop body, so we have little choice. + * inside iterator constroctor, the expr should be copied to + * current memory context (stmt_mcontext). Without it, it will be released + * by next exec_eval_cleanup. The iterator constructor should + * be called under stmt memory context. */ - arr = DatumGetArrayTypePCopy(value); + iterator = sbroutines->create_foreach_a_iterator(expr, + expr_typid, expr_typmod, + stmt->slice, target_typid, + target_typmod); /* Clean up any leftover temporary memory */ exec_eval_cleanup(estate); - /* Slice dimension must be less than or equal to array dimension */ - if (stmt->slice < 0 || stmt->slice > ARR_NDIM(arr)) - ereport(ERROR, - (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR), - errmsg("slice dimension (%d) is out of the valid range 0..%d", - stmt->slice, ARR_NDIM(arr)))); - - /* Set up the loop variable and see if it is of an array type */ - loop_var = estate->datums[stmt->varno]; - if (loop_var->dtype == PLPGSQL_DTYPE_REC || - loop_var->dtype == PLPGSQL_DTYPE_ROW) - { - /* - * Record/row variable is certainly not of array type, and might not - * be initialized at all yet, so don't try to get its type - */ - loop_var_elem_type = InvalidOid; - } - else - loop_var_elem_type = get_element_type(plpgsql_exec_get_datum_type(estate, - loop_var)); + tmp_cxt = AllocSetContextCreate(stmt_mcontext, + "FOREACH IN ARRAY temporary cxt", + ALLOCSET_DEFAULT_SIZES); - /* - * Sanity-check the loop variable type. We don't try very hard here, and - * should not be too picky since it's possible that exec_assign_value can - * coerce values of different types. But it seems worthwhile to complain - * if the array-ness of the loop variable is not right. - */ - if (stmt->slice > 0 && loop_var_elem_type == InvalidOid) - ereport(ERROR, - (errcode(ERRCODE_DATATYPE_MISMATCH), - errmsg("FOREACH ... SLICE loop variable must be of an array type"))); - if (stmt->slice == 0 && loop_var_elem_type != InvalidOid) - ereport(ERROR, - (errcode(ERRCODE_DATATYPE_MISMATCH), - errmsg("FOREACH loop variable must not be of an array type"))); + MemoryContextSwitchTo(tmp_cxt); - /* Create an iterator to step through the array */ - array_iterator = array_create_iterator(arr, stmt->slice, NULL); - - /* Identify iterator result type */ - if (stmt->slice > 0) - { - /* When slicing, nominal type of result is same as array type */ - iterator_result_type = arrtype; - iterator_result_typmod = arrtypmod; - } - else - { - /* Without slicing, results are individual array elements */ - iterator_result_type = ARR_ELEMTYPE(arr); - iterator_result_typmod = arrtypmod; - } - - /* Iterate over the array elements or slices */ - while (array_iterate(array_iterator, &value, &isnull)) + while (iterator->iterate(iterator, &value, &isnull, &typid, &typmod)) { found = true; /* looped at least once */ @@ -3117,12 +3082,9 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt) MemoryContextSwitchTo(oldcontext); /* Assign current element/slice to the loop variable */ - exec_assign_value(estate, loop_var, value, isnull, - iterator_result_type, iterator_result_typmod); + exec_assign_value(estate, target_var, value, isnull, typid, typmod); - /* In slice case, value is temporary; must free it to avoid leakage */ - if (stmt->slice > 0) - pfree(DatumGetPointer(value)); + MemoryContextReset(tmp_cxt); /* * Execute the statements @@ -3131,7 +3093,7 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt) LOOP_RC_PROCESSING(stmt->label, break); - MemoryContextSwitchTo(stmt_mcontext); + MemoryContextSwitchTo(tmp_cxt); } /* Restore memory context state */ @@ -5537,6 +5499,53 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate, break; } + case PLPGSQL_DTYPE_ROW: + { + PLpgSQL_row *row = (PLpgSQL_row *) datum; + + if (!row->rowtupdesc) + { + int i; + + row->rowtupdesc = CreateTemplateTupleDesc(row->nfields); + + for (i = 0; i < row->nfields; i++) + { + PLpgSQL_datum *var = estate->datums[row->varnos[i]]; + Oid vartypid; + int32 vartypmod; + Oid varcollation; + + /* + * We cannot use fieldnames for tupdescentry, because + * these names can be suffixed by name of row variable. + * Unfortunately, the PLpgSQL_recfield is not casted to + * PLpgSQL_variable. + */ + plpgsql_exec_get_datum_type_info(estate, var, + &vartypid, &vartypmod, + &varcollation); + + TupleDescInitEntry(row->rowtupdesc, i + 1, + var->refname, vartypid, vartypmod, + 0); + TupleDescInitEntryCollation(row->rowtupdesc, i + 1, + varcollation); + } + + TupleDescFinalize(row->rowtupdesc); + + /* Make sure we have a valid type/typmod setting */ + BlessTupleDesc(row->rowtupdesc); + } + + *typeId = row->rowtupdesc->tdtypeid; + *typMod = row->rowtupdesc->tdtypmod; + /* composite types are never collatable */ + *collation = InvalidOid; + break; + } + case PLPGSQL_DTYPE_REC: { PLpgSQL_rec *rec = (PLpgSQL_rec *) datum; diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h index addb14a9959..5cbdb4ecd9d 100644 --- a/src/pl/plpgsql/src/plpgsql.h +++ b/src/pl/plpgsql/src/plpgsql.h @@ -299,6 +299,7 @@ typedef struct PLpgSQL_datum { PLpgSQL_datum_type dtype; int dno; + char *refname; } PLpgSQL_datum; /* @@ -444,9 +445,9 @@ typedef struct PLpgSQL_recfield { PLpgSQL_datum_type dtype; int dno; + char *fieldname; /* name of field */ /* end of PLpgSQL_datum fields */ - char *fieldname; /* name of field */ int recparentno; /* dno of parent record */ int nextfield; /* dno of next child, or -1 if none */ uint64 rectupledescid; /* record's tupledesc ID as of last lookup */ diff --git a/src/pl/plpgsql/src/sql/plpgsql_foreach.sql b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql new file mode 100644 index 00000000000..a64004417af --- /dev/null +++ b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql @@ -0,0 +1,252 @@ +-- input must be a JSON array +do $$ +declare x numeric; +begin + foreach x in array NULL::jsonb -- fail + loop + raise notice '%', x; + end loop; +end; +$$; + +do $$ +declare x numeric; +begin + foreach x in array jsonb '10' -- fail + loop + raise notice '%', x; + end loop; +end; +$$; + +do $$ +declare x numeric; +begin + foreach x in array jsonb '{}' -- fail + loop + raise notice '%', x; + end loop; +end; +$$; + +-- numeric to numeric +do $$ +declare x numeric; +begin + foreach x in array jsonb '[10,20,30,3.14, null]' + loop + raise notice '%', x; + end loop; +end; +$$; + +-- numeric to int by cast +do $$ +declare x int; +begin + foreach x in array jsonb '[10,20,30,3.14, null]' + loop + raise notice '%', x; + end loop; +end; +$$; + +-- test of FOUND variable +do $$ +declare x int; +begin + foreach x in array jsonb '[10]' + loop + raise notice '%', x; + end loop; + raise notice 'FOUND: %', found; +end; +$$; + +-- test of FOUND variable +do $$ +declare x int; +begin + foreach x in array jsonb '[]' + loop + raise notice '%', x; + end loop; + raise notice 'FOUND: %', found; +end; +$$; + +-- conversion "3.14" to int should to fail due IO cast +do $$ +declare x int; +begin + foreach x in array jsonb '["10",20,30,"3.14"]' + loop + raise notice '%', x; + end loop; +end; +$$; + +do $$ +declare x boolean; +begin + foreach x in array jsonb '[true, false]' + loop + if x then + raise notice 'true'; + else + raise notice 'false'; + end if; + end loop; +end; +$$; + +-- jsonb to jsonb +do $$ +declare x jsonb; +begin + foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]' + loop + raise notice '%', x; + end loop; +end; +$$; + +-- jsonb to json +do $$ +declare x json; +begin + foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]' + loop + raise notice '%', x; + end loop; +end; +$$; + +-- iteration over composites +do $$ +declare x int; y numeric; z varchar; +begin + foreach x, y, z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]' + loop + raise notice 'x: %, y: %, z: %', x, y, z; + end loop; +end; +$$; + +create type t3 as (x int, y numeric, z varchar); + +do $$ +declare c t3; +begin + foreach c in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]' + loop + raise notice 'x: %, y: %, z: %', c.x, c.y, c.z; + end loop; +end; +$$; + +do $$ +declare c t3; +begin + foreach c.x, c.y, c.z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]' + loop + raise notice 'x: %, y: %, z: %', c.x, c.y, c.z; + end loop; +end; +$$; + +drop type t3; + +-- target can be a array +do $$ +declare x int[]; +begin + foreach x in array jsonb '[[1,2,3],[4,5,6]]' + loop + raise notice '% % %', x[1], x[2], x[3]; + end loop; +end; +$$; + +do $$ +declare x varchar[]; +begin + foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]' + loop + raise notice '% %', x[1], x[2]; + end loop; +end; +$$; + +do $$ +declare x varchar[]; +begin + foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]' + loop + raise notice '% %', x[1], x[2]; + end loop; +end; +$$; + +do $$ +declare x int[]; y varchar; +begin + foreach x, y in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]' + loop + raise notice '% % %, y: %', x[1], x[2], x[3], y; + end loop; +end; +$$; + +create type t2 as (x int[], y varchar); + +do $$ +declare c t2; +begin + foreach c in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]' + loop + raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y; + end loop; +end; +$$; + +drop type t2; + +-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING +do $$ +declare x int; +begin + foreach x in array jsonb '[1,2,3,4,5]' + loop + exit when x = 3; + raise notice '%', x; + end loop; +end; +$$; + +do $$ +declare x int; +begin + foreach x in array jsonb '[1,2,3,4,5]' + loop + continue when x % 2 = 0; + raise notice '%', x; + end loop; +end; +$$; + +-- Variable instead of string +DO $$ +declare + x int; + arr jsonb; +begin + select jsonb_agg(i) into arr + from generate_series(1,3) g(i); + + foreach x in array arr + loop + raise notice '%', x; + end loop; +end; +$$; -- 2.53.0
