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[PATCH v48 1/3] Subscripting for jsonb 3+ messages / 3 participants [nested] [flat]
* [PATCH v48 1/3] Subscripting for jsonb @ 2020-12-18 16:19 Dmitrii Dolgov <[email protected]> 0 siblings, 0 replies; 3+ messages in thread From: Dmitrii Dolgov @ 2020-12-18 16:19 UTC (permalink / raw) Subscripting implementation for jsonb. It does not support slices, does not have a limit for number of subscripts and for assignment expects a replace value to be of jsonb type. There is also one functional difference in assignment via subscripting from jsonb_set, when an original jsonb container is NULL, subscripting replaces it with an empty jsonb and proceed with assignment. For the sake of code reuse, some parts of jsonb functionality were rearranged to allow use the same functions for jsonb_set and assign subscripting operation. The original idea belongs to Oleg Bartunov. Reviewed-by: Tom Lane, Arthur Zakirov, Pavel Stehule, Dian M Fay --- doc/src/sgml/json.sgml | 51 ++++ src/backend/utils/adt/Makefile | 1 + src/backend/utils/adt/jsonb_util.c | 76 ++++- src/backend/utils/adt/jsonbsubs.c | 413 ++++++++++++++++++++++++++++ src/backend/utils/adt/jsonfuncs.c | 180 ++++++------ src/include/catalog/pg_proc.dat | 4 + src/include/catalog/pg_type.dat | 3 +- src/include/utils/jsonb.h | 6 +- src/test/regress/expected/jsonb.out | 272 +++++++++++++++++- src/test/regress/sql/jsonb.sql | 84 +++++- 10 files changed, 985 insertions(+), 105 deletions(-) create mode 100644 src/backend/utils/adt/jsonbsubs.c diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml index 5b9a5557a4..3ace5e444b 100644 --- a/doc/src/sgml/json.sgml +++ b/doc/src/sgml/json.sgml @@ -602,6 +602,57 @@ SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @> '{"tags": ["qu </para> </sect2> + <sect2 id="jsonb-subscripting"> + <title><type>jsonb</type> Subscripting</title> + <para> + The <type>jsonb</type> data type supports array-style subscripting expressions + to extract and modify elements. Nested values can be indicated by chaining + subscripting expressions, following the same rules as the <literal>path</literal> + argument in the <literal>jsonb_set</literal> function. If a <type>jsonb</type> + value is an array, numeric subscripts start at zero, and negative integers count + backwards from the last element of the array. Slice expressions are not supported. + The result of a subscripting expression is always of the jsonb data type. + </para> + + <para> + An example of subscripting syntax: +<programlisting> + +-- Extract object value by key +SELECT ('{"a": 1}'::jsonb)['a']; + +-- Extract nested object value by key path +SELECT ('{"a": {"b": {"c": 1}}}'::jsonb)['a']['b']['c']; + +-- Extract array element by index +SELECT ('[1, "2", null]'::jsonb)[1]; + +-- Update object value by key. Note the quotes around '1': the assigned +-- value must be of the jsonb type as well +UPDATE table_name SET jsonb_field['key'] = '1'; + +-- Filter records using a WHERE clause with subscripting. Since the result of +-- subscripting is jsonb, the value we compare it against must also be jsonb. +-- The double quotes make "value" also a valid jsonb string. +SELECT * FROM table_name WHERE jsonb_field['key'] = '"value"'; +</programlisting> + + <type>jsonb</type> assignment via subscripting handles a few edge cases + differently from <literal>jsonb_set</literal>. When a source <type>jsonb</type> + is <literal>NULL</literal>, assignment via subscripting will proceed as if + it was an empty JSON object: + +<programlisting> +-- Where jsonb_field was NULL, it is now {"a": 1} +UPDATE table_name SET jsonb_field['a'] = '1'; + +-- Where jsonb_field was NULL, it is now [1] +UPDATE table_name SET jsonb_field[0] = '1'; +</programlisting> + + </para> + </sect2> + <sect2> <title>Transforms</title> diff --git a/src/backend/utils/adt/Makefile b/src/backend/utils/adt/Makefile index 82732146d3..279ff15ade 100644 --- a/src/backend/utils/adt/Makefile +++ b/src/backend/utils/adt/Makefile @@ -50,6 +50,7 @@ OBJS = \ jsonb_op.o \ jsonb_util.o \ jsonfuncs.o \ + jsonbsubs.o \ jsonpath.o \ jsonpath_exec.o \ jsonpath_gram.o \ diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c index 4eeffa1424..41a1c1f9bb 100644 --- a/src/backend/utils/adt/jsonb_util.c +++ b/src/backend/utils/adt/jsonb_util.c @@ -68,18 +68,29 @@ static JsonbValue *pushJsonbValueScalar(JsonbParseState **pstate, JsonbIteratorToken seq, JsonbValue *scalarVal); +JsonbValue * +JsonbToJsonbValue(Jsonb *jsonb) +{ + JsonbValue *val = (JsonbValue *) palloc(sizeof(JsonbValue)); + + val->type = jbvBinary; + val->val.binary.data = &jsonb->root; + val->val.binary.len = VARSIZE(jsonb) - VARHDRSZ; + + return val; +} + /* * Turn an in-memory JsonbValue into a Jsonb for on-disk storage. * - * There isn't a JsonbToJsonbValue(), because generally we find it more - * convenient to directly iterate through the Jsonb representation and only - * really convert nested scalar values. JsonbIteratorNext() does this, so that - * clients of the iteration code don't have to directly deal with the binary - * representation (JsonbDeepContains() is a notable exception, although all - * exceptions are internal to this module). In general, functions that accept - * a JsonbValue argument are concerned with the manipulation of scalar values, - * or simple containers of scalar values, where it would be inconvenient to - * deal with a great amount of other state. + * Generally we find it more convenient to directly iterate through the Jsonb + * representation and only really convert nested scalar values. + * JsonbIteratorNext() does this, so that clients of the iteration code don't + * have to directly deal with the binary representation (JsonbDeepContains() is + * a notable exception, although all exceptions are internal to this module). + * In general, functions that accept a JsonbValue argument are concerned with + * the manipulation of scalar values, or simple containers of scalar values, + * where it would be inconvenient to deal with a great amount of other state. */ Jsonb * JsonbValueToJsonb(JsonbValue *val) @@ -563,6 +574,30 @@ pushJsonbValue(JsonbParseState **pstate, JsonbIteratorToken seq, JsonbValue *res = NULL; JsonbValue v; JsonbIteratorToken tok; + int i; + + if (jbval && (seq == WJB_ELEM || seq == WJB_VALUE) && jbval->type == jbvObject) + { + pushJsonbValue(pstate, WJB_BEGIN_OBJECT, NULL); + for (i = 0; i < jbval->val.object.nPairs; i++) + { + pushJsonbValue(pstate, WJB_KEY, &jbval->val.object.pairs[i].key); + pushJsonbValue(pstate, WJB_VALUE, &jbval->val.object.pairs[i].value); + } + + return pushJsonbValue(pstate, WJB_END_OBJECT, NULL); + } + + if (jbval && (seq == WJB_ELEM || seq == WJB_VALUE) && jbval->type == jbvArray) + { + pushJsonbValue(pstate, WJB_BEGIN_ARRAY, NULL); + for (i = 0; i < jbval->val.array.nElems; i++) + { + pushJsonbValue(pstate, WJB_ELEM, &jbval->val.array.elems[i]); + } + + return pushJsonbValue(pstate, WJB_END_ARRAY, NULL); + } if (!jbval || (seq != WJB_ELEM && seq != WJB_VALUE) || jbval->type != jbvBinary) @@ -573,9 +608,30 @@ pushJsonbValue(JsonbParseState **pstate, JsonbIteratorToken seq, /* unpack the binary and add each piece to the pstate */ it = JsonbIteratorInit(jbval->val.binary.data); + + if ((jbval->val.binary.data->header & JB_FSCALAR) && *pstate) + { + tok = JsonbIteratorNext(&it, &v, true); + Assert(tok == WJB_BEGIN_ARRAY); + Assert(v.type == jbvArray && v.val.array.rawScalar); + + tok = JsonbIteratorNext(&it, &v, true); + Assert(tok == WJB_ELEM); + + res = pushJsonbValueScalar(pstate, seq, &v); + + tok = JsonbIteratorNext(&it, &v, true); + Assert(tok == WJB_END_ARRAY); + Assert(it == NULL); + + return res; + } + while ((tok = JsonbIteratorNext(&it, &v, false)) != WJB_DONE) res = pushJsonbValueScalar(pstate, tok, - tok < WJB_BEGIN_ARRAY ? &v : NULL); + tok < WJB_BEGIN_ARRAY || + (tok == WJB_BEGIN_ARRAY && + v.val.array.rawScalar) ? &v : NULL); return res; } diff --git a/src/backend/utils/adt/jsonbsubs.c b/src/backend/utils/adt/jsonbsubs.c new file mode 100644 index 0000000000..5237414be4 --- /dev/null +++ b/src/backend/utils/adt/jsonbsubs.c @@ -0,0 +1,413 @@ +/*------------------------------------------------------------------------- + * + * jsonbsubs.c + * Subscripting support functions for jsonb. + * + * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/utils/adt/jsonbsubs.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "executor/execExpr.h" +#include "nodes/makefuncs.h" +#include "nodes/nodeFuncs.h" +#include "nodes/subscripting.h" +#include "parser/parse_coerce.h" +#include "parser/parse_expr.h" +#include "utils/jsonb.h" +#include "utils/jsonfuncs.h" +#include "utils/builtins.h" +#include "utils/lsyscache.h" + + +/* SubscriptingRefState.workspace for jsonb subscripting execution */ +typedef struct JsonbSubWorkspace +{ + bool expectArray; /* jsonb root is expected to be an array */ + Oid *indexOid; /* OID of coerced subscript expression, + could be only integer or text */ + Datum *index; /* Subscript values in Datum format */ +} JsonbSubWorkspace; + + +/* + * Finish parse analysis of a SubscriptingRef expression for a jsonb. + * + * Transform the subscript expressions, coerce them to text, + * and determine the result type of the SubscriptingRef node. + */ +static void +jsonb_subscript_transform(SubscriptingRef *sbsref, + List *indirection, + ParseState *pstate, + bool isSlice, + bool isAssignment) +{ + List *upperIndexpr = NIL; + ListCell *idx; + + /* + * Transform and convert the subscript expressions. Jsonb subscripting does + * not support slices, look only and the upper index. + */ + foreach(idx, indirection) + { + A_Indices *ai = lfirst_node(A_Indices, idx); + Node *subExpr; + + if (isSlice) + { + Node *expr = ai->uidx ? ai->uidx : ai->lidx; + + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("jsonb subscript does not support slices"), + parser_errposition(pstate, exprLocation(expr)))); + } + + if (ai->uidx) + { + Oid subExprType = InvalidOid, + targetType = UNKNOWNOID; + + subExpr = transformExpr(pstate, ai->uidx, pstate->p_expr_kind); + subExprType = exprType(subExpr); + + if (subExprType != UNKNOWNOID) + { + Oid targets[2] = {INT4OID, TEXTOID}; + + /* + * Jsonb can handle multiple subscript types, but cases when a + * subscript could be coerced to multiple target types must be + * avoided, similar to overloaded functions. It could be + * possibly extend with jsonpath in the future. + */ + for (int i = 0; i < 2; i++) + { + if (can_coerce_type(1, &subExprType, &targets[i], COERCION_IMPLICIT)) + { + /* + * One type has already succeeded, it means there are + * two coercion targets possible, failure. + */ + if (targetType != UNKNOWNOID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("subscript type is not supported"), + errhint("Jsonb subscript must be coerced " + "only to one type, integer or text."), + parser_errposition(pstate, exprLocation(subExpr)))); + + targetType = targets[i]; + } + } + + /* + * No suitable types were found, failure. + */ + if (targetType == UNKNOWNOID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("subscript type is not supported"), + errhint("Jsonb subscript must be coerced to either integer or text"), + parser_errposition(pstate, exprLocation(subExpr)))); + } + else + targetType = TEXTOID; + + /* + * We known from can_coerce_type that coercion will succeed, so + * coerce_type could be used. Note the implicit coercion context, + * which is required to handle subscripts of different types, + * similar to overloaded functions. + */ + subExpr = coerce_type(pstate, + subExpr, subExprType, + targetType, -1, + COERCION_IMPLICIT, + COERCE_IMPLICIT_CAST, + -1); + if (subExpr == NULL) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("jsonb subscript must have text type"), + parser_errposition(pstate, exprLocation(subExpr)))); + } + else + { + /* + * Slice with omitted upper bound. Should not happen as we already + * errored out on slice earlier, but handle this just in case. + */ + Assert(isSlice && ai->is_slice); + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("jsonb subscript does not support slices"), + parser_errposition(pstate, exprLocation(ai->uidx)))); + } + + upperIndexpr = lappend(upperIndexpr, subExpr); + } + + /* store the transformed lists into the SubscriptRef node */ + sbsref->refupperindexpr = upperIndexpr; + sbsref->reflowerindexpr = NIL; + + /* Determine the result type of the subscripting operation; always jsonb */ + sbsref->refrestype = JSONBOID; + sbsref->reftypmod = -1; +} + +/* + * During execution, process the subscripts in a SubscriptingRef expression. + * + * The subscript expressions are already evaluated in Datum form in the + * SubscriptingRefState's arrays. Check and convert them as necessary. + * + * If any subscript is NULL, we throw error in assignment cases, or in fetch + * cases set result to NULL and return false (instructing caller to skip the + * rest of the SubscriptingRef sequence). + */ +static bool +jsonb_subscript_check_subscripts(ExprState *state, + ExprEvalStep *op, + ExprContext *econtext) +{ + SubscriptingRefState *sbsrefstate = op->d.sbsref_subscript.state; + JsonbSubWorkspace *workspace = (JsonbSubWorkspace *) sbsrefstate->workspace; + + /* + * In case if the first subscript is an integer, the source jsonb is + * expected to be an array. This information is not used directly, all such + * cases are handled within corresponding jsonb assign functions. But if + * the source jsonb is NULL the expected type will be used to construct an + * empty source. + */ + if (sbsrefstate->numupper > 0 && sbsrefstate->upperprovided[0] && + !sbsrefstate->upperindexnull[0] && workspace->indexOid[0] == INT4OID) + workspace->expectArray = true; + + /* Process upper subscripts */ + for (int i = 0; i < sbsrefstate->numupper; i++) + { + if (sbsrefstate->upperprovided[i]) + { + /* If any index expr yields NULL, result is NULL or error */ + if (sbsrefstate->upperindexnull[i]) + { + if (sbsrefstate->isassignment) + ereport(ERROR, + (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), + errmsg("jsonb subscript in assignment must not be null"))); + *op->resnull = true; + return false; + } + + /* + * For jsonb fetch and assign functions we need to provide path in + * text format. Convert if it's not already text. + */ + if (workspace->indexOid[i] == INT4OID) + { + Datum datum = sbsrefstate->upperindex[i]; + char *cs = DatumGetCString(DirectFunctionCall1(int4out, datum)); + workspace->index[i] = CStringGetTextDatum(cs); + } + else + workspace->index[i] = sbsrefstate->upperindex[i]; + } + } + + return true; +} + +/* + * Evaluate SubscriptingRef fetch for a jsonb element. + * + * Source container is in step's result variable (it's known not NULL, since + * we set fetch_strict to true). + */ +static void +jsonb_subscript_fetch(ExprState *state, + ExprEvalStep *op, + ExprContext *econtext) +{ + SubscriptingRefState *sbsrefstate = op->d.sbsref.state; + JsonbSubWorkspace *workspace = (JsonbSubWorkspace *) sbsrefstate->workspace; + Jsonb *jsonbSource; + + /* Should not get here if source jsonb (or any subscript) is null */ + Assert(!(*op->resnull)); + + jsonbSource = DatumGetJsonbP(*op->resvalue); + *op->resvalue = jsonb_get_element(jsonbSource, + workspace->index, + sbsrefstate->numupper, + op->resnull, + false); +} + +/* + * Evaluate SubscriptingRef assignment for a jsonb element assignment. + * + * Input container (possibly null) is in result area, replacement value is in + * SubscriptingRefState's replacevalue/replacenull. + */ +static void +jsonb_subscript_assign(ExprState *state, + ExprEvalStep *op, + ExprContext *econtext) +{ + SubscriptingRefState *sbsrefstate = op->d.sbsref.state; + JsonbSubWorkspace *workspace = (JsonbSubWorkspace *) sbsrefstate->workspace; + Jsonb *jsonbSource; + JsonbValue *replacevalue; + + if (sbsrefstate->replacenull) + { + replacevalue = (JsonbValue *) palloc(sizeof(JsonbValue)); + replacevalue->type = jbvNull; + } + else + replacevalue = + JsonbToJsonbValue(DatumGetJsonbP(sbsrefstate->replacevalue)); + + /* + * In case if the input container is null, set up an empty jsonb and + * proceed with the assignment. + */ + if (*op->resnull) + { + JsonbValue *newSource = (JsonbValue *) palloc(sizeof(JsonbValue)); + + /* + * To avoid any surprising results, set up an empty jsonb array in case + * of an array is expected (i.e. the first subscript is integer), + * otherwise jsonb object. + */ + if (workspace->expectArray) + { + newSource->type = jbvArray; + newSource->val.array.nElems = 0; + newSource->val.array.rawScalar = false; + } + else + { + newSource->type = jbvObject; + newSource->val.object.nPairs = 0; + } + + jsonbSource = JsonbValueToJsonb(newSource); + *op->resnull = false; + } + else + jsonbSource = DatumGetJsonbP(*op->resvalue); + + *op->resvalue = jsonb_set_element(jsonbSource, + workspace->index, + sbsrefstate->numupper, + replacevalue); + /* The result is never NULL, so no need to change *op->resnull */ +} + +/* + * Compute old jsonb element value for a SubscriptingRef assignment + * expression. Will only be called if the new-value subexpression + * contains SubscriptingRef or FieldStore. This is the same as the + * regular fetch case, except that we have to handle a null jsonb, + * and the value should be stored into the SubscriptingRefState's + * prevvalue/prevnull fields. + */ +static void +jsonb_subscript_fetch_old(ExprState *state, + ExprEvalStep *op, + ExprContext *econtext) +{ + SubscriptingRefState *sbsrefstate = op->d.sbsref.state; + + if (*op->resnull) + { + /* whole jsonb is null, so any element is too */ + sbsrefstate->prevvalue = (Datum) 0; + sbsrefstate->prevnull = true; + } + else + { + Jsonb *jsonbSource = DatumGetJsonbP(*op->resvalue); + sbsrefstate->prevvalue = jsonb_get_element(jsonbSource, + sbsrefstate->upperindex, + sbsrefstate->numupper, + &sbsrefstate->prevnull, + false); + } +} + +/* + * Set up execution state for a jsonb subscript operation. Opposite to the + * arrays subscription, there is no limit for number of subscripts as jsonb + * type itself doesn't have nesting limits. + */ +static void +jsonb_exec_setup(const SubscriptingRef *sbsref, + SubscriptingRefState *sbsrefstate, + SubscriptExecSteps *methods) +{ + JsonbSubWorkspace *workspace; + ListCell *lc; + int nupper = sbsref->refupperindexpr->length; + char *ptr; + + /* Allocate type-specific workspace with space for per-subscript data */ + workspace = palloc0(MAXALIGN(sizeof(JsonbSubWorkspace)) + + nupper * (sizeof(Datum) + sizeof(Oid))); + workspace->expectArray = false; + ptr = ((char *) workspace) + MAXALIGN(sizeof(JsonbSubWorkspace)); + workspace->indexOid = (Oid *) ptr; + ptr += nupper * sizeof(Oid); + workspace->index = (Datum *) ptr; + + sbsrefstate->workspace = workspace; + + /* Collect subscript data types necessary at execution time */ + foreach(lc, sbsref->refupperindexpr) + { + Node *expr = lfirst(lc); + int i = foreach_current_index(lc); + + workspace->indexOid[i] = exprType(expr); + } + + /* + * Pass back pointers to appropriate step execution functions. + */ + methods->sbs_check_subscripts = jsonb_subscript_check_subscripts; + methods->sbs_fetch = jsonb_subscript_fetch; + methods->sbs_assign = jsonb_subscript_assign; + methods->sbs_fetch_old = jsonb_subscript_fetch_old; +} + +/* + * jsonb_subscript_handler + * Subscripting handler for jsonb. + * + */ +Datum +jsonb_subscript_handler(PG_FUNCTION_ARGS) +{ + static const SubscriptRoutines sbsroutines = { + .transform = jsonb_subscript_transform, + .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 */ + }; + + PG_RETURN_POINTER(&sbsroutines); +} diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c index 69100feab7..5a0ba6b220 100644 --- a/src/backend/utils/adt/jsonfuncs.c +++ b/src/backend/utils/adt/jsonfuncs.c @@ -461,18 +461,18 @@ static Datum populate_domain(DomainIOData *io, Oid typid, const char *colname, /* functions supporting jsonb_delete, jsonb_set and jsonb_concat */ static JsonbValue *IteratorConcat(JsonbIterator **it1, JsonbIterator **it2, JsonbParseState **state); -static JsonbValue *setPath(JsonbIterator **it, Datum *path_elems, +extern JsonbValue *setPath(JsonbIterator **it, Datum *path_elems, bool *path_nulls, int path_len, - JsonbParseState **st, int level, Jsonb *newval, + JsonbParseState **st, int level, JsonbValue *newval, int op_type); static void setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls, int path_len, JsonbParseState **st, int level, - Jsonb *newval, uint32 npairs, int op_type); + JsonbValue *newval, uint32 npairs, int op_type); static void setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls, int path_len, JsonbParseState **st, - int level, Jsonb *newval, uint32 nelems, int op_type); -static void addJsonbToParseState(JsonbParseState **jbps, Jsonb *jb); + int level, + JsonbValue *newval, uint32 nelems, int op_type); /* function supporting iterate_json_values */ static void iterate_values_scalar(void *state, char *token, JsonTokenType tokentype); @@ -1448,13 +1448,9 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) ArrayType *path = PG_GETARG_ARRAYTYPE_P(1); Datum *pathtext; bool *pathnulls; + bool isnull; int npath; - int i; - bool have_object = false, - have_array = false; - JsonbValue *jbvp = NULL; - JsonbValue jbvbuf; - JsonbContainer *container; + Datum res; /* * If the array contains any null elements, return NULL, on the grounds @@ -1469,9 +1465,26 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) deconstruct_array(path, TEXTOID, -1, false, TYPALIGN_INT, &pathtext, &pathnulls, &npath); - /* Identify whether we have object, array, or scalar at top-level */ - container = &jb->root; + res = jsonb_get_element(jb, pathtext, npath, &isnull, as_text); + if (isnull) + PG_RETURN_NULL(); + else + PG_RETURN_DATUM(res); +} + +Datum +jsonb_get_element(Jsonb *jb, Datum *path, int npath, bool *isnull, bool as_text) +{ + JsonbContainer *container = &jb->root; + JsonbValue *jbvp = NULL; + int i; + bool have_object = false, + have_array = false; + + *isnull = false; + + /* Identify whether we have object, array, or scalar at top-level */ if (JB_ROOT_IS_OBJECT(jb)) have_object = true; else if (JB_ROOT_IS_ARRAY(jb) && !JB_ROOT_IS_SCALAR(jb)) @@ -1496,7 +1509,7 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) { if (as_text) { - PG_RETURN_TEXT_P(cstring_to_text(JsonbToCString(NULL, + return PointerGetDatum(cstring_to_text(JsonbToCString(NULL, container, VARSIZE(jb)))); } @@ -1512,22 +1525,25 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) if (have_object) { jbvp = getKeyJsonValueFromContainer(container, - VARDATA(pathtext[i]), - VARSIZE(pathtext[i]) - VARHDRSZ, - &jbvbuf); + VARDATA(path[i]), + VARSIZE(path[i]) - VARHDRSZ, + NULL); } else if (have_array) { long lindex; uint32 index; - char *indextext = TextDatumGetCString(pathtext[i]); + char *indextext = TextDatumGetCString(path[i]); char *endptr; errno = 0; lindex = strtol(indextext, &endptr, 10); if (endptr == indextext || *endptr != '\0' || errno != 0 || lindex > INT_MAX || lindex < INT_MIN) - PG_RETURN_NULL(); + { + *isnull = true; + return PointerGetDatum(NULL); + } if (lindex >= 0) { @@ -1545,7 +1561,10 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) nelements = JsonContainerSize(container); if (-lindex > nelements) - PG_RETURN_NULL(); + { + *isnull = true; + return PointerGetDatum(NULL); + } else index = nelements + lindex; } @@ -1555,11 +1574,15 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) else { /* scalar, extraction yields a null */ - PG_RETURN_NULL(); + *isnull = true; + return PointerGetDatum(NULL); } if (jbvp == NULL) - PG_RETURN_NULL(); + { + *isnull = true; + return PointerGetDatum(NULL); + } else if (i == npath - 1) break; @@ -1581,9 +1604,12 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) if (as_text) { if (jbvp->type == jbvNull) - PG_RETURN_NULL(); + { + *isnull = true; + return PointerGetDatum(NULL); + } - PG_RETURN_TEXT_P(JsonbValueAsText(jbvp)); + return PointerGetDatum(JsonbValueAsText(jbvp)); } else { @@ -1594,6 +1620,28 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text) } } +Datum +jsonb_set_element(Jsonb* jb, Datum *path, int path_len, + JsonbValue *newval) +{ + JsonbValue *res; + JsonbParseState *state = NULL; + JsonbIterator *it; + bool *path_nulls = palloc0(path_len * sizeof(bool)); + + if (newval->type == jbvArray && newval->val.array.rawScalar) + *newval = newval->val.array.elems[0]; + + it = JsonbIteratorInit(&jb->root); + + res = setPath(&it, path, path_nulls, path_len, &state, 0, + newval, JB_PATH_CREATE); + + pfree(path_nulls); + + PG_RETURN_JSONB_P(JsonbValueToJsonb(res)); +} + /* * Return the text representation of the given JsonbValue. */ @@ -4151,58 +4199,6 @@ jsonb_strip_nulls(PG_FUNCTION_ARGS) PG_RETURN_POINTER(JsonbValueToJsonb(res)); } -/* - * Add values from the jsonb to the parse state. - * - * If the parse state container is an object, the jsonb is pushed as - * a value, not a key. - * - * This needs to be done using an iterator because pushJsonbValue doesn't - * like getting jbvBinary values, so we can't just push jb as a whole. - */ -static void -addJsonbToParseState(JsonbParseState **jbps, Jsonb *jb) -{ - JsonbIterator *it; - JsonbValue *o = &(*jbps)->contVal; - JsonbValue v; - JsonbIteratorToken type; - - it = JsonbIteratorInit(&jb->root); - - Assert(o->type == jbvArray || o->type == jbvObject); - - if (JB_ROOT_IS_SCALAR(jb)) - { - (void) JsonbIteratorNext(&it, &v, false); /* skip array header */ - Assert(v.type == jbvArray); - (void) JsonbIteratorNext(&it, &v, false); /* fetch scalar value */ - - switch (o->type) - { - case jbvArray: - (void) pushJsonbValue(jbps, WJB_ELEM, &v); - break; - case jbvObject: - (void) pushJsonbValue(jbps, WJB_VALUE, &v); - break; - default: - elog(ERROR, "unexpected parent of nested structure"); - } - } - else - { - while ((type = JsonbIteratorNext(&it, &v, false)) != WJB_DONE) - { - if (type == WJB_KEY || type == WJB_VALUE || type == WJB_ELEM) - (void) pushJsonbValue(jbps, type, &v); - else - (void) pushJsonbValue(jbps, type, NULL); - } - } - -} - /* * SQL function jsonb_pretty (jsonb) * @@ -4474,7 +4470,8 @@ jsonb_set(PG_FUNCTION_ARGS) { Jsonb *in = PG_GETARG_JSONB_P(0); ArrayType *path = PG_GETARG_ARRAYTYPE_P(1); - Jsonb *newval = PG_GETARG_JSONB_P(2); + Jsonb *newjsonb = PG_GETARG_JSONB_P(2); + JsonbValue *newval = JsonbToJsonbValue(newjsonb); bool create = PG_GETARG_BOOL(3); JsonbValue *res = NULL; Datum *path_elems; @@ -4632,7 +4629,8 @@ jsonb_insert(PG_FUNCTION_ARGS) { Jsonb *in = PG_GETARG_JSONB_P(0); ArrayType *path = PG_GETARG_ARRAYTYPE_P(1); - Jsonb *newval = PG_GETARG_JSONB_P(2); + Jsonb *newjsonb = PG_GETARG_JSONB_P(2); + JsonbValue *newval = JsonbToJsonbValue(newjsonb); bool after = PG_GETARG_BOOL(3); JsonbValue *res = NULL; Datum *path_elems; @@ -4787,10 +4785,10 @@ IteratorConcat(JsonbIterator **it1, JsonbIterator **it2, * All path elements before the last must already exist * whatever bits in op_type are set, or nothing is done. */ -static JsonbValue * +JsonbValue * setPath(JsonbIterator **it, Datum *path_elems, bool *path_nulls, int path_len, - JsonbParseState **st, int level, Jsonb *newval, int op_type) + JsonbParseState **st, int level, JsonbValue *newval, int op_type) { JsonbValue v; JsonbIteratorToken r; @@ -4843,11 +4841,11 @@ setPath(JsonbIterator **it, Datum *path_elems, static void setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls, int path_len, JsonbParseState **st, int level, - Jsonb *newval, uint32 npairs, int op_type) + JsonbValue *newval, uint32 npairs, int op_type) { - JsonbValue v; int i; - JsonbValue k; + JsonbValue k, + v; bool done = false; if (level >= path_len || path_nulls[level]) @@ -4864,7 +4862,7 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls, newkey.val.string.val = VARDATA_ANY(path_elems[level]); (void) pushJsonbValue(st, WJB_KEY, &newkey); - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_VALUE, newval); } for (i = 0; i < npairs; i++) @@ -4895,7 +4893,7 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls, if (!(op_type & JB_PATH_DELETE)) { (void) pushJsonbValue(st, WJB_KEY, &k); - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_VALUE, newval); } done = true; } @@ -4918,7 +4916,7 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls, newkey.val.string.val = VARDATA_ANY(path_elems[level]); (void) pushJsonbValue(st, WJB_KEY, &newkey); - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_VALUE, newval); } (void) pushJsonbValue(st, r, &k); @@ -4950,7 +4948,7 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls, static void setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls, int path_len, JsonbParseState **st, int level, - Jsonb *newval, uint32 nelems, int op_type) + JsonbValue *newval, uint32 nelems, int op_type) { JsonbValue v; int idx, @@ -4998,7 +4996,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls, (op_type & JB_PATH_CREATE_OR_INSERT)) { Assert(newval != NULL); - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_ELEM, newval); done = true; } @@ -5014,7 +5012,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls, r = JsonbIteratorNext(it, &v, true); /* skip */ if (op_type & (JB_PATH_INSERT_BEFORE | JB_PATH_CREATE)) - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_ELEM, newval); /* * We should keep current value only in case of @@ -5025,7 +5023,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls, (void) pushJsonbValue(st, r, &v); if (op_type & (JB_PATH_INSERT_AFTER | JB_PATH_REPLACE)) - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_ELEM, newval); done = true; } @@ -5059,7 +5057,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls, if ((op_type & JB_PATH_CREATE_OR_INSERT) && !done && level == path_len - 1 && i == nelems - 1) { - addJsonbToParseState(st, newval); + (void) pushJsonbValue(st, WJB_ELEM, newval); } } } diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 139f4a08bd..feae8cc4b0 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -11239,6 +11239,10 @@ { oid => '9256', descr => 'raw array subscripting support', proname => 'raw_array_subscript_handler', prorettype => 'internal', proargtypes => 'internal', prosrc => 'raw_array_subscript_handler' }, +# type subscripting support +{ oid => '6098', descr => 'jsonb subscripting logic', + proname => 'jsonb_subscript_handler', prorettype => 'internal', + proargtypes => 'internal', prosrc => 'jsonb_subscript_handler' }, # collation management functions { oid => '3445', descr => 'import collations from operating system', diff --git a/src/include/catalog/pg_type.dat b/src/include/catalog/pg_type.dat index 62018f063a..4a530ca907 100644 --- a/src/include/catalog/pg_type.dat +++ b/src/include/catalog/pg_type.dat @@ -444,7 +444,8 @@ { oid => '3802', array_type_oid => '3807', descr => 'Binary JSON', typname => 'jsonb', typlen => '-1', typbyval => 'f', typcategory => 'U', typinput => 'jsonb_in', typoutput => 'jsonb_out', typreceive => 'jsonb_recv', - typsend => 'jsonb_send', typalign => 'i', typstorage => 'x' }, + typsend => 'jsonb_send', typalign => 'i', typstorage => 'x', + typsubscript => 'jsonb_subscript_handler' }, { oid => '4072', array_type_oid => '4073', descr => 'JSON path', typname => 'jsonpath', typlen => '-1', typbyval => 'f', typcategory => 'U', typinput => 'jsonpath_in', typoutput => 'jsonpath_out', diff --git a/src/include/utils/jsonb.h b/src/include/utils/jsonb.h index 5860011693..64f1ccbf77 100644 --- a/src/include/utils/jsonb.h +++ b/src/include/utils/jsonb.h @@ -392,6 +392,7 @@ extern JsonbValue *pushJsonbValue(JsonbParseState **pstate, extern JsonbIterator *JsonbIteratorInit(JsonbContainer *container); extern JsonbIteratorToken JsonbIteratorNext(JsonbIterator **it, JsonbValue *val, bool skipNested); +extern JsonbValue *JsonbToJsonbValue(Jsonb *jsonb); extern Jsonb *JsonbValueToJsonb(JsonbValue *val); extern bool JsonbDeepContains(JsonbIterator **val, JsonbIterator **mContained); @@ -407,5 +408,8 @@ extern char *JsonbToCStringIndent(StringInfo out, JsonbContainer *in, extern bool JsonbExtractScalar(JsonbContainer *jbc, JsonbValue *res); extern const char *JsonbTypeName(JsonbValue *jb); - +extern Datum jsonb_set_element(Jsonb *jb, Datum *path, int path_len, + JsonbValue *newval); +extern Datum jsonb_get_element(Jsonb *jb, Datum *path, int npath, + bool *isnull, bool as_text); #endif /* __JSONB_H__ */ diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out index 1e6c6ef200..46bf2e2353 100644 --- a/src/test/regress/expected/jsonb.out +++ b/src/test/regress/expected/jsonb.out @@ -4599,7 +4599,7 @@ select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'use_ {"a": 1, "b": null} (1 row) -\pset null +\pset null '' -- jsonb_insert select jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"'); jsonb_insert @@ -4729,6 +4729,276 @@ HINT: Try using the function jsonb_set to replace key value. select jsonb_insert('{"a": {"b": "value"}}', '{a, b}', '"new_value"', true); ERROR: cannot replace existing key HINT: Try using the function jsonb_set to replace key value. +-- jsonb subscript +select ('123'::jsonb)['a']; + jsonb +------- + +(1 row) + +select ('123'::jsonb)[0]; + jsonb +------- + +(1 row) + +select ('123'::jsonb)[NULL]; + jsonb +------- + +(1 row) + +select ('{"a": 1}'::jsonb)['a']; + jsonb +------- + 1 +(1 row) + +select ('{"a": 1}'::jsonb)[0]; + jsonb +------- + +(1 row) + +select ('{"a": 1}'::jsonb)['not_exist']; + jsonb +------- + +(1 row) + +select ('{"a": 1}'::jsonb)[NULL]; + jsonb +------- + +(1 row) + +select ('[1, "2", null]'::jsonb)['a']; + jsonb +------- + +(1 row) + +select ('[1, "2", null]'::jsonb)[0]; + jsonb +------- + 1 +(1 row) + +select ('[1, "2", null]'::jsonb)['1']; + jsonb +------- + "2" +(1 row) + +select ('[1, "2", null]'::jsonb)[1.0]; +ERROR: subscript type is not supported +LINE 1: select ('[1, "2", null]'::jsonb)[1.0]; + ^ +HINT: Jsonb subscript must be coerced to either integer or text +select ('[1, "2", null]'::jsonb)[2]; + jsonb +------- + null +(1 row) + +select ('[1, "2", null]'::jsonb)[3]; + jsonb +------- + +(1 row) + +select ('[1, "2", null]'::jsonb)[-2]; + jsonb +------- + "2" +(1 row) + +select ('[1, "2", null]'::jsonb)[1]['a']; + jsonb +------- + +(1 row) + +select ('[1, "2", null]'::jsonb)[1][0]; + jsonb +------- + +(1 row) + +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['b']; + jsonb +------- + "c" +(1 row) + +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['d']; + jsonb +----------- + [1, 2, 3] +(1 row) + +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['d'][1]; + jsonb +------- + 2 +(1 row) + +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['d']['a']; + jsonb +------- + +(1 row) + +select ('{"a": {"a1": {"a2": "aaa"}}, "b": "bbb", "c": "ccc"}'::jsonb)['a']['a1']; + jsonb +--------------- + {"a2": "aaa"} +(1 row) + +select ('{"a": {"a1": {"a2": "aaa"}}, "b": "bbb", "c": "ccc"}'::jsonb)['a']['a1']['a2']; + jsonb +------- + "aaa" +(1 row) + +select ('{"a": {"a1": {"a2": "aaa"}}, "b": "bbb", "c": "ccc"}'::jsonb)['a']['a1']['a2']['a3']; + jsonb +------- + +(1 row) + +select ('{"a": ["a1", {"b1": ["aaa", "bbb", "ccc"]}], "b": "bb"}'::jsonb)['a'][1]['b1']; + jsonb +----------------------- + ["aaa", "bbb", "ccc"] +(1 row) + +select ('{"a": ["a1", {"b1": ["aaa", "bbb", "ccc"]}], "b": "bb"}'::jsonb)['a'][1]['b1'][2]; + jsonb +------- + "ccc" +(1 row) + +-- slices are not supported +select ('{"a": 1}'::jsonb)['a':'b']; +ERROR: jsonb subscript does not support slices +LINE 1: select ('{"a": 1}'::jsonb)['a':'b']; + ^ +select ('[1, "2", null]'::jsonb)[1:2]; +ERROR: jsonb subscript does not support slices +LINE 1: select ('[1, "2", null]'::jsonb)[1:2]; + ^ +select ('[1, "2", null]'::jsonb)[:2]; +ERROR: jsonb subscript does not support slices +LINE 1: select ('[1, "2", null]'::jsonb)[:2]; + ^ +select ('[1, "2", null]'::jsonb)[1:]; +ERROR: jsonb subscript does not support slices +LINE 1: select ('[1, "2", null]'::jsonb)[1:]; + ^ +select ('[1, "2", null]'::jsonb)[:]; +ERROR: jsonb subscript does not support slices +create TEMP TABLE test_jsonb_subscript ( + id int, + test_json jsonb +); +insert into test_jsonb_subscript values +(1, '{}'), -- empty jsonb +(2, '{"key": "value"}'); -- jsonb with data +-- update empty jsonb +update test_jsonb_subscript set test_json['a'] = '1' where id = 1; +select * from test_jsonb_subscript; + id | test_json +----+------------------ + 2 | {"key": "value"} + 1 | {"a": 1} +(2 rows) + +-- update jsonb with some data +update test_jsonb_subscript set test_json['a'] = '1' where id = 2; +select * from test_jsonb_subscript; + id | test_json +----+-------------------------- + 1 | {"a": 1} + 2 | {"a": 1, "key": "value"} +(2 rows) + +-- replace jsonb +update test_jsonb_subscript set test_json['a'] = '"test"'; +select * from test_jsonb_subscript; + id | test_json +----+------------------------------- + 1 | {"a": "test"} + 2 | {"a": "test", "key": "value"} +(2 rows) + +-- replace by object +update test_jsonb_subscript set test_json['a'] = '{"b": 1}'::jsonb; +select * from test_jsonb_subscript; + id | test_json +----+--------------------------------- + 1 | {"a": {"b": 1}} + 2 | {"a": {"b": 1}, "key": "value"} +(2 rows) + +-- replace by array +update test_jsonb_subscript set test_json['a'] = '[1, 2, 3]'::jsonb; +select * from test_jsonb_subscript; + id | test_json +----+---------------------------------- + 1 | {"a": [1, 2, 3]} + 2 | {"a": [1, 2, 3], "key": "value"} +(2 rows) + +-- use jsonb subscription in where clause +select * from test_jsonb_subscript where test_json['key'] = '"value"'; + id | test_json +----+---------------------------------- + 2 | {"a": [1, 2, 3], "key": "value"} +(1 row) + +select * from test_jsonb_subscript where test_json['key_doesnt_exists'] = '"value"'; + id | test_json +----+----------- +(0 rows) + +select * from test_jsonb_subscript where test_json['key'] = '"wrong_value"'; + id | test_json +----+----------- +(0 rows) + +-- NULL +update test_jsonb_subscript set test_json[NULL] = '1'; +ERROR: jsonb subscript in assignment must not be null +update test_jsonb_subscript set test_json['another_key'] = NULL; +select * from test_jsonb_subscript; + id | test_json +----+------------------------------------------------------- + 1 | {"a": [1, 2, 3], "another_key": null} + 2 | {"a": [1, 2, 3], "key": "value", "another_key": null} +(2 rows) + +-- NULL as jsonb source +insert into test_jsonb_subscript values (3, NULL); +update test_jsonb_subscript set test_json['a'] = '1' where id = 3; +select * from test_jsonb_subscript; + id | test_json +----+------------------------------------------------------- + 1 | {"a": [1, 2, 3], "another_key": null} + 2 | {"a": [1, 2, 3], "key": "value", "another_key": null} + 3 | {"a": 1} +(3 rows) + +update test_jsonb_subscript set test_json = NULL where id = 3; +update test_jsonb_subscript set test_json[0] = '1'; +select * from test_jsonb_subscript; + id | test_json +----+--------------------------------------------------------------- + 1 | {"0": 1, "a": [1, 2, 3], "another_key": null} + 2 | {"0": 1, "a": [1, 2, 3], "key": "value", "another_key": null} + 3 | [1] +(3 rows) + -- jsonb to tsvector select to_tsvector('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'::jsonb); to_tsvector diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql index b6409767f6..20aa8fe0e2 100644 --- a/src/test/regress/sql/jsonb.sql +++ b/src/test/regress/sql/jsonb.sql @@ -1177,7 +1177,7 @@ select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'retu select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'delete_key') as delete_key; select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'use_json_null') as use_json_null; -\pset null +\pset null '' -- jsonb_insert select jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"'); @@ -1208,6 +1208,88 @@ select jsonb_insert('{"a": {"b": "value"}}', '{a, c}', '"new_value"', true); select jsonb_insert('{"a": {"b": "value"}}', '{a, b}', '"new_value"'); select jsonb_insert('{"a": {"b": "value"}}', '{a, b}', '"new_value"', true); +-- jsonb subscript +select ('123'::jsonb)['a']; +select ('123'::jsonb)[0]; +select ('123'::jsonb)[NULL]; +select ('{"a": 1}'::jsonb)['a']; +select ('{"a": 1}'::jsonb)[0]; +select ('{"a": 1}'::jsonb)['not_exist']; +select ('{"a": 1}'::jsonb)[NULL]; +select ('[1, "2", null]'::jsonb)['a']; +select ('[1, "2", null]'::jsonb)[0]; +select ('[1, "2", null]'::jsonb)['1']; +select ('[1, "2", null]'::jsonb)[1.0]; +select ('[1, "2", null]'::jsonb)[2]; +select ('[1, "2", null]'::jsonb)[3]; +select ('[1, "2", null]'::jsonb)[-2]; +select ('[1, "2", null]'::jsonb)[1]['a']; +select ('[1, "2", null]'::jsonb)[1][0]; +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['b']; +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['d']; +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['d'][1]; +select ('{"a": 1, "b": "c", "d": [1, 2, 3]}'::jsonb)['d']['a']; +select ('{"a": {"a1": {"a2": "aaa"}}, "b": "bbb", "c": "ccc"}'::jsonb)['a']['a1']; +select ('{"a": {"a1": {"a2": "aaa"}}, "b": "bbb", "c": "ccc"}'::jsonb)['a']['a1']['a2']; +select ('{"a": {"a1": {"a2": "aaa"}}, "b": "bbb", "c": "ccc"}'::jsonb)['a']['a1']['a2']['a3']; +select ('{"a": ["a1", {"b1": ["aaa", "bbb", "ccc"]}], "b": "bb"}'::jsonb)['a'][1]['b1']; +select ('{"a": ["a1", {"b1": ["aaa", "bbb", "ccc"]}], "b": "bb"}'::jsonb)['a'][1]['b1'][2]; + +-- slices are not supported +select ('{"a": 1}'::jsonb)['a':'b']; +select ('[1, "2", null]'::jsonb)[1:2]; +select ('[1, "2", null]'::jsonb)[:2]; +select ('[1, "2", null]'::jsonb)[1:]; +select ('[1, "2", null]'::jsonb)[:]; + +create TEMP TABLE test_jsonb_subscript ( + id int, + test_json jsonb +); + +insert into test_jsonb_subscript values +(1, '{}'), -- empty jsonb +(2, '{"key": "value"}'); -- jsonb with data + +-- update empty jsonb +update test_jsonb_subscript set test_json['a'] = '1' where id = 1; +select * from test_jsonb_subscript; + +-- update jsonb with some data +update test_jsonb_subscript set test_json['a'] = '1' where id = 2; +select * from test_jsonb_subscript; + +-- replace jsonb +update test_jsonb_subscript set test_json['a'] = '"test"'; +select * from test_jsonb_subscript; + +-- replace by object +update test_jsonb_subscript set test_json['a'] = '{"b": 1}'::jsonb; +select * from test_jsonb_subscript; + +-- replace by array +update test_jsonb_subscript set test_json['a'] = '[1, 2, 3]'::jsonb; +select * from test_jsonb_subscript; + +-- use jsonb subscription in where clause +select * from test_jsonb_subscript where test_json['key'] = '"value"'; +select * from test_jsonb_subscript where test_json['key_doesnt_exists'] = '"value"'; +select * from test_jsonb_subscript where test_json['key'] = '"wrong_value"'; + +-- NULL +update test_jsonb_subscript set test_json[NULL] = '1'; +update test_jsonb_subscript set test_json['another_key'] = NULL; +select * from test_jsonb_subscript; + +-- NULL as jsonb source +insert into test_jsonb_subscript values (3, NULL); +update test_jsonb_subscript set test_json['a'] = '1' where id = 3; +select * from test_jsonb_subscript; + +update test_jsonb_subscript set test_json = NULL where id = 3; +update test_jsonb_subscript set test_json[0] = '1'; +select * from test_jsonb_subscript; + -- jsonb to tsvector select to_tsvector('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'::jsonb); -- 2.21.0 --m4t3wpskod5t4yye Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="v48-0002-Filling-gaps-in-jsonb.patch" ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: linux cachestat in file Readv and Prefetch @ 2024-02-17 23:10 Tomas Vondra <[email protected]> 2024-03-14 18:04 ` Re: linux cachestat in file Readv and Prefetch Robert Haas <[email protected]> 0 siblings, 1 reply; 3+ messages in thread From: Tomas Vondra @ 2024-02-17 23:10 UTC (permalink / raw) To: pgsql-hackers On 1/18/24 01:25, Cedric Villemain wrote: > Hi, > > I was testing the index prefetch and streamIO patches and I added > cachestat() syscall to get a better view of the prefetching. > > It's a new linux syscall, it requires 6.5, it provides numerous > interesting information from the VM for the range of pages examined. > It's way way faster than the old mincore() and provides much more > valuable information: > > uint64 nr_cache; /* Number of cached pages */ > uint64 nr_dirty; /* Number of dirty pages */ > uint64 nr_writeback; /* Number of pages marked for writeback. */ > uint64 nr_evicted; /* Number of pages evicted from the cache. */ > /* > * Number of recently evicted pages. A page is recently evicted if its > * last eviction was recent enough that its reentry to the cache would > * indicate that it is actively being used by the system, and that there > * is memory pressure on the system. > */ > uint64 nr_recently_evicted; > > > While here I also added some quick tweaks to suspend prefetching on > memory pressure. I may be missing some important bit behind this idea, but this does not seem like a great idea to me. The comment added to FilePrefetch says this: /* * last time we visit this file (somewhere), nr_recently_evicted pages * of the range were just removed from vm cache, it's a sign a memory * pressure. so do not prefetch further. * it is hard to guess if it is always the right choice in absence of * more information like: * - prefetching distance expected overall * - access pattern/backend maybe */ Firstly, is this even a good way to detect memory pressure? It's clearly limited to a single 1GB segment, so what's the chance we'll even see the "pressure" on a big database with many files? If we close/reopen the file (which on large databases we tend to do very often) how does that affect the data reported for the file descriptor? I'm not sure I even agree with the idea that we should stop prefetching when there is memory pressure. IMHO it's perfectly fine to keep prefetching stuff even if it triggers eviction of unnecessary pages from page cache. That's kinda why the eviction exists. > It's working but I have absolutely not checked the performance impact of > my additions. > Well ... I'd argue at least some basic evaluation of performance is a rather important / expected part of a proposal for a patch that aims to improve a performance-focused feature. It's impossible to have any sort of discussion about such patch without that. regards -- Tomas Vondra EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: linux cachestat in file Readv and Prefetch 2024-02-17 23:10 Re: linux cachestat in file Readv and Prefetch Tomas Vondra <[email protected]> @ 2024-03-14 18:04 ` Robert Haas <[email protected]> 0 siblings, 0 replies; 3+ messages in thread From: Robert Haas @ 2024-03-14 18:04 UTC (permalink / raw) To: Tomas Vondra <[email protected]>; +Cc: pgsql-hackers On Sat, Feb 17, 2024 at 6:10 PM Tomas Vondra <[email protected]> wrote: > I may be missing some important bit behind this idea, but this does not > seem like a great idea to me. The comment added to FilePrefetch says this: > > /* > * last time we visit this file (somewhere), nr_recently_evicted pages > * of the range were just removed from vm cache, it's a sign a memory > * pressure. so do not prefetch further. > * it is hard to guess if it is always the right choice in absence of > * more information like: > * - prefetching distance expected overall > * - access pattern/backend maybe > */ > > Firstly, is this even a good way to detect memory pressure? It's clearly > limited to a single 1GB segment, so what's the chance we'll even see the > "pressure" on a big database with many files? > > If we close/reopen the file (which on large databases we tend to do very > often) how does that affect the data reported for the file descriptor? > > I'm not sure I even agree with the idea that we should stop prefetching > when there is memory pressure. IMHO it's perfectly fine to keep > prefetching stuff even if it triggers eviction of unnecessary pages from > page cache. That's kinda why the eviction exists. I agree with all of these criticisms. I think it's the job of pg_prewarm to do what the user requests, not to second-guess whether the user requested the right thing. One of the things that frustrates people about the ring-buffer system is that it's hard to get all of your data cached in shared_buffers by just reading it, e.g. SELECT * FROM my_table. If pg_prewarm also isn't guaranteed to actually read your data, and may decide that your data didn't need to be read after all, then what exactly is a user supposed to do if they're absolutely sure that they know better than PostgreSQL itself and want to guarantee that their data actually does get read? So I think a feature like this would at the very least need to be optional, but it's unclear to me why we'd want it at all, and I feel like Cedric's email doesn't really answer that question. I suppose that if you could detect useless prefetching and skip it, you'd save a bit of work, but under what circumstances does anyone use pg_prewarm so aggressively as to make that a problem, and why wouldn't the solution be for the user to just calm down a little bit? There shouldn't be any particular reason why the user can't know both the size of shared_buffers and the approximate size of the OS cache; indeed, they can probably know the latter much more reliably than PostgreSQL itself can. So it should be fairly easy to avoid just prefetching more data than will fit, and then you don't have to worry about any of this. And you'll probably get a better result, too, because, along the same lines as Tomas's remarks above, I doubt that this would be an accurate method anyway. > Well ... I'd argue at least some basic evaluation of performance is a > rather important / expected part of a proposal for a patch that aims to > improve a performance-focused feature. It's impossible to have any sort > of discussion about such patch without that. Right. I'm going to mark this patch as Rejected in the CommitFest application for now. If in subsequent discussion that comes to seem like the wrong result, then we can revise accordingly, but right now it looks extremely unlikely to me that this is something that we'd want. -- Robert Haas EDB: http://www.enterprisedb.com ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2024-03-14 18:04 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2020-12-18 16:19 [PATCH v48 1/3] Subscripting for jsonb Dmitrii Dolgov <[email protected]> 2024-02-17 23:10 Re: linux cachestat in file Readv and Prefetch Tomas Vondra <[email protected]> 2024-03-14 18:04 ` Re: linux cachestat in file Readv and Prefetch Robert Haas <[email protected]>
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