Copy data from heap tuples instead of using references

The general rule is:
If the data is used within the bounds of table_open ... table_close > no need to copy
If the data is required for use even after the table is closed > copy

(cherry picked from commit dc9da7630f)

src/backend/columnar/columnar_tableam.c

@@ -3000,7 +3000,7 @@ InstalledExtensionVersionColumnar(void)
 		}
 
 
-		installedExtensionVersion = text_to_cstring(DatumGetTextPP(installedVersion));
+		installedExtensionVersion = text_to_cstring(DatumGetTextPCopy(installedVersion));
 	}
 	else
 	{

src/backend/distributed/commands/domain.c

@@ -175,7 +175,7 @@ RecreateDomainStmt(Oid domainOid)
 		 *
 		 * There is no supported way to go from a cooked expression to a raw expression.
 		 */
-		constraint->cooked_expr = TextDatumGetCString(conbin);
+		constraint->cooked_expr = text_to_cstring(DatumGetTextPCopy(conbin));
 
 		stmt->constraints = lappend(stmt->constraints, constraint);
 	}

src/backend/distributed/commands/role.c

@@ -337,6 +337,7 @@ ExtractEncryptedPassword(Oid roleOid)
 
 	Datum passwordDatum = heap_getattr(tuple, Anum_pg_authid_rolpassword,
 									   pgAuthIdDescription, &isNull);
+	char *passwordCstring = text_to_cstring(DatumGetTextPCopy(passwordDatum));
 
 	table_close(pgAuthId, AccessShareLock);
 	ReleaseSysCache(tuple);
@@ -346,7 +347,7 @@ ExtractEncryptedPassword(Oid roleOid)
 		return NULL;
 	}
 
-	return pstrdup(TextDatumGetCString(passwordDatum));
+	return pstrdup(passwordCstring);
 }
 
 
@@ -398,7 +399,7 @@ GenerateAlterRoleSetIfExistsCommandList(HeapTuple tuple,
 	 */
 	for (i = 0; i < nconfigs; i++)
 	{
-		char *config = TextDatumGetCString(configs[i]);
+		char *config = text_to_cstring(DatumGetTextPCopy(configs[i]));
 		stmt->setstmt = MakeVariableSetStmt(config);
 		commandList = lappend(commandList,
 							  (void *) CreateAlterRoleSetIfExistsCommand(stmt));

src/backend/distributed/commands/text_search.c

@@ -207,6 +207,7 @@ GetTextSearchDictionaryInitOptions(HeapTuple tup, Form_pg_ts_dict dict)
 	List *initOptionDefElemList = NIL;
 	if (!isnull)
 	{
+		/* TODO: might need copying */
 		initOptionDefElemList = deserialize_deflist(dictinitoption);
 	}
 

src/backend/distributed/deparser/citus_ruleutils.c

@@ -152,7 +152,7 @@ get_extension_version(Oid extensionId)
 										  RelationGetDescr(relation), &isNull);
 		if (!isNull)
 		{
-			versionName = text_to_cstring(DatumGetTextPP(versionDatum));
+			versionName = text_to_cstring(DatumGetTextPCopy(versionDatum));
 		}
 	}
 

src/backend/distributed/metadata/metadata_cache.c

@@ -67,6 +67,7 @@
 #include "utils/datum.h"
 #include "utils/elog.h"
 #include "utils/hsearch.h"
+#include "utils/jsonb.h"
 #if PG_VERSION_NUM >= PG_VERSION_13
 #include "common/hashfn.h"
 #endif
@@ -2249,7 +2250,7 @@ InstalledExtensionVersion(void)
 		MemoryContext oldMemoryContext = MemoryContextSwitchTo(
 			MetadataCacheMemoryContext);
 
-		installedExtensionVersion = text_to_cstring(DatumGetTextPP(installedVersion));
+		installedExtensionVersion = text_to_cstring(DatumGetTextPCopy(installedVersion));
 
 		MemoryContextSwitchTo(oldMemoryContext);
 	}
@@ -4883,6 +4884,10 @@ DistNodeMetadata(void)
 							"could not find any entries in pg_dist_metadata")));
 	}
 
+	/* copy the jsonb result before closing the table */
+	/* since that memory can be freed */
+	metadata = JsonbPGetDatum(DatumGetJsonbPCopy(metadata));
+
 	systable_endscan(scanDescriptor);
 	table_close(pgDistNodeMetadata, AccessShareLock);
 

src/backend/distributed/planner/multi_explain.c

@@ -1286,6 +1286,7 @@ ExplainAnalyzeDestPutTuple(TupleDestination *self, Task *task,
 			return;
 		}
 
+		/* TODO: might need copying */
 		char *fetchedExplainAnalyzePlan = TextDatumGetCString(explainAnalyze);
 		double fetchedExplainAnalyzeExecutionDuration = DatumGetFloat8(executionDuration);