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[PATCH v48 1/3] Subscripting for jsonb
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* [PATCH v48 1/3] Subscripting for jsonb
@ 2020-12-18 16:19  Dmitrii Dolgov <[email protected]>
  0 siblings, 0 replies; 5+ 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-&gt;'guid', jdoc-&gt;'name' FROM api WHERE jdoc @&gt; '{"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] 5+ messages in thread

* Re: Improve documentation for pg_upgrade, standbys and rsync
@ 2022-04-05 16:38  Robert Haas <[email protected]>
  0 siblings, 1 reply; 5+ messages in thread

From: Robert Haas @ 2022-04-05 16:38 UTC (permalink / raw)
  To: Stephen Frost <[email protected]>; +Cc: Laurenz Albe <[email protected]>; [email protected]

On Mon, Jul 26, 2021 at 3:11 PM Stephen Frost <[email protected]> wrote:
> * Laurenz Albe ([email protected]) wrote:
> > Thanks for looking at this!
>
> Sure.  Thanks for working on it!

Stephen, do you intend to do something about this patch in terms of
getting it committed? You're the only reviewer but haven't responded
to the thread for more than 5 months.

I don't feel that I know this area of the documentation well enough to
feel comfortable passing judgement on whether this change is an
improvement or not. However I do feel somewhat uncomfortable with
this:

-   <step>
-    <title>Prepare for standby server upgrades</title>
-
-    <para>
-     If you are upgrading standby servers using methods outlined in
section <xref
-     linkend="pgupgrade-step-replicas"/>, verify that the old standby
-     servers are caught up by running <application>pg_controldata</application>
-     against the old primary and standby clusters.  Verify that the
-     <quote>Latest checkpoint location</quote> values match in all clusters.
-     (There will be a mismatch if old standby servers were shut down
-     before the old primary or if the old standby servers are still running.)
-     Also, make sure <varname>wal_level</varname> is not set to
-     <literal>minimal</literal> in the
<filename>postgresql.conf</filename> file on the
-     new primary cluster.
-    </para>
-   </step>

Right now, we say that you should stop the standby servers and then
prepared for standby server upgrades. With this patch, we say that you
should first prepare for standby server upgrades, and then stop the
standby servers. But the last part of the text about preparing for
standby server upgrades now mentions things to be done after carrying
out the next step where the servers are actually stopped. That seems
confusing. Perhaps we need two separate steps here, one to be
performed before stopping both servers and the other after.

Also, let me express my general terror at the idea of anyone actually
using this procedure.

Regards,

-- 
Robert Haas
EDB: http://www.enterprisedb.com






^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* Re: Improve documentation for pg_upgrade, standbys and rsync
@ 2022-04-05 17:10  Stephen Frost <[email protected]>
  parent: Robert Haas <[email protected]>
  0 siblings, 2 replies; 5+ messages in thread

From: Stephen Frost @ 2022-04-05 17:10 UTC (permalink / raw)
  To: Robert Haas <[email protected]>; +Cc: Laurenz Albe <[email protected]>; [email protected]

Greetings,

* Robert Haas ([email protected]) wrote:
> On Mon, Jul 26, 2021 at 3:11 PM Stephen Frost <[email protected]> wrote:
> > * Laurenz Albe ([email protected]) wrote:
> > > Thanks for looking at this!
> >
> > Sure.  Thanks for working on it!
> 
> Stephen, do you intend to do something about this patch in terms of
> getting it committed? You're the only reviewer but haven't responded
> to the thread for more than 5 months.

I tried to be clear in the last email on the thread, the one which you
just responded to, here:

* Stephen Frost ([email protected]) wrote:
> This, of course, all comes back to the original complaint I had about
> documenting this approach, which is that these things should only be
> done by someone extremely familiar with the PG codebase, until and
> unless we write an actual tool to do this.

To be more explicit though- we should write a tool to do this.  We
shouldn't try to document a way to do it because it's hard to get right.
While rsync is very capable, what's needed to really do this goes beyond
what we could reasonably put into any rsync command or really even into
a documented procedure.  I get that we already have it documented (and
I'll note that doing so was against my recommendation..) and that some
folks (likely those who follow this mailing list) have had success using
it, but I'd really rather we just take it out and put it on a wiki
somewhere as a "we need a tool that does this stuff" and hope that
someone finds time to write one.

> I don't feel that I know this area of the documentation well enough to
> feel comfortable passing judgement on whether this change is an
> improvement or not. However I do feel somewhat uncomfortable with
> this:
> 
> -   <step>
> -    <title>Prepare for standby server upgrades</title>
> -
> -    <para>
> -     If you are upgrading standby servers using methods outlined in
> section <xref
> -     linkend="pgupgrade-step-replicas"/>, verify that the old standby
> -     servers are caught up by running <application>pg_controldata</application>
> -     against the old primary and standby clusters.  Verify that the
> -     <quote>Latest checkpoint location</quote> values match in all clusters.
> -     (There will be a mismatch if old standby servers were shut down
> -     before the old primary or if the old standby servers are still running.)
> -     Also, make sure <varname>wal_level</varname> is not set to
> -     <literal>minimal</literal> in the
> <filename>postgresql.conf</filename> file on the
> -     new primary cluster.
> -    </para>
> -   </step>
> 
> Right now, we say that you should stop the standby servers and then
> prepared for standby server upgrades. With this patch, we say that you
> should first prepare for standby server upgrades, and then stop the
> standby servers. But the last part of the text about preparing for
> standby server upgrades now mentions things to be done after carrying
> out the next step where the servers are actually stopped. That seems
> confusing. Perhaps we need two separate steps here, one to be
> performed before stopping both servers and the other after.

It should really be both- things to do on the primary ahead of time
(truncate all unlogged tables, make sure there aren't any orphaned
temporary tables, etc), and then things to do on the replicas after
shutting the primary down (basically, make sure they are fully caught up
with where the primary was at shutdown).  I tried to explain that in my
prior email but perhaps didn't do a very good job.

> Also, let me express my general terror at the idea of anyone actually
> using this procedure.

I mean, yeah, I agree.

Thanks,

Stephen


Attachments:

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^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* Re: Improve documentation for pg_upgrade, standbys and rsync
@ 2022-04-05 18:59  Bruce Momjian <[email protected]>
  parent: Stephen Frost <[email protected]>
  1 sibling, 0 replies; 5+ messages in thread

From: Bruce Momjian @ 2022-04-05 18:59 UTC (permalink / raw)
  To: Stephen Frost <[email protected]>; +Cc: Robert Haas <[email protected]>; Laurenz Albe <[email protected]>; [email protected]

On Tue, Apr  5, 2022 at 01:10:38PM -0400, Stephen Frost wrote:
> To be more explicit though- we should write a tool to do this.  We
> shouldn't try to document a way to do it because it's hard to get right.
> While rsync is very capable, what's needed to really do this goes beyond
> what we could reasonably put into any rsync command or really even into
> a documented procedure.  I get that we already have it documented (and
> I'll note that doing so was against my recommendation..) and that some
> folks (likely those who follow this mailing list) have had success using
> it, but I'd really rather we just take it out and put it on a wiki
> somewhere as a "we need a tool that does this stuff" and hope that
> someone finds time to write one.

Well, I think pg_upgrade needs a tool, let alone for standby upgrades,
but 13 years in, no one has written one, so I am not holding my breath. 
Also, we need to document the procedure _somewhere_ --- if we don't the
only procedure is embedded in a tool. and that seems even worse than
what we have now.

> It should really be both- things to do on the primary ahead of time
> (truncate all unlogged tables, make sure there aren't any orphaned
> temporary tables, etc), and then things to do on the replicas after
> shutting the primary down (basically, make sure they are fully caught up
> with where the primary was at shutdown).  I tried to explain that in my
> prior email but perhaps didn't do a very good job.
> 
> > Also, let me express my general terror at the idea of anyone actually
> > using this procedure.
> 
> I mean, yeah, I agree.

I thought that was true for pg_upgrade in general?  ;-)

Seems like a pull up your sleeves and hold your nose --- I am good at
those tasks.  ;-)  Should I work on this?  Tangentially, I see that my
old macros fastgetattr and heap_getattr have finally been retired by
commit e27f4ee0a7.  :-)

-- 
  Bruce Momjian  <[email protected]>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson






^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* Re: Improve documentation for pg_upgrade, standbys and rsync
@ 2022-04-08 05:14  Laurenz Albe <[email protected]>
  parent: Stephen Frost <[email protected]>
  1 sibling, 0 replies; 5+ messages in thread

From: Laurenz Albe @ 2022-04-08 05:14 UTC (permalink / raw)
  To: Stephen Frost <[email protected]>; Robert Haas <[email protected]>; +Cc: [email protected]

On Tue, 2022-04-05 at 13:10 -0400, Stephen Frost wrote:
> * Robert Haas ([email protected]) wrote:
> On Mon, Jul 26, 2021 at 3:11 PM Stephen Frost <[email protected]> wrote:
> > * Laurenz Albe ([email protected]) wrote:
> > > > Thanks for looking at this!
> > > 
> > > Sure.  Thanks for working on it!
> > 
> > Stephen, do you intend to do something about this patch in terms of
> > getting it committed? You're the only reviewer but haven't responded
> > to the thread for more than 5 months.
> 
> I tried to be clear in the last email on the thread, the one which you
> just responded to, here:
> 
> * Stephen Frost ([email protected]) wrote:
> > This, of course, all comes back to the original complaint I had about
> > documenting this approach, which is that these things should only be
> > done by someone extremely familiar with the PG codebase, until and
> > unless we write an actual tool to do this.
> 
> To be more explicit though- we should write a tool to do this.  We
> shouldn't try to document a way to do it because it's hard to get right.

I see no agreement on this patch.  I'll withdraw it from the commitfest
to avoid hogging resources.  Thanks everyone for the review.

Yours,
Laurenz Albe







^ permalink  raw  reply  [nested|flat] 5+ messages in thread


end of thread, other threads:[~2022-04-08 05:14 UTC | newest]

Thread overview: 5+ 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]>
2022-04-05 16:38 Re: Improve documentation for pg_upgrade, standbys and rsync Robert Haas <[email protected]>
2022-04-05 17:10 ` Re: Improve documentation for pg_upgrade, standbys and rsync Stephen Frost <[email protected]>
2022-04-05 18:59   ` Re: Improve documentation for pg_upgrade, standbys and rsync Bruce Momjian <[email protected]>
2022-04-08 05:14   ` Re: Improve documentation for pg_upgrade, standbys and rsync Laurenz Albe <[email protected]>

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