Add telemetry for access methods

Add telemetry for tracking access methods used, number of pages for
each access method, and number of instances using each access method.

.github/workflows/code_style.yaml

@@ -66,7 +66,7 @@ jobs:
       - name: Run codespell
         run: |
           find . -type f \( -name "*.c" -or -name "*.h" -or -name "*.yaml" -or -name "*.sh" \) \
-            -exec codespell -L "inh,larg,inout" {} \+
+            -exec codespell -L "brin,inh,larg,inout" {} \+
 
   cc_checks:
     name: Check code formatting

.unreleased/pr_6810

@@ -0,0 +1 @@
+Implements: #6810 Add telemetry for access methods

src/jsonb_utils.c

@@ -57,6 +57,45 @@ ts_jsonb_add_str(JsonbParseState *state, const char *key, const char *value)
 	ts_jsonb_add_value(state, key, &json_value);
 }
 
+void
+ts_jsonb_set_value_by_type(JsonbValue *value, Oid typeid, Datum datum)
+{
+	switch (typeid)
+	{
+		Oid typeOut;
+		bool isvarlena;
+		char *str;
+
+		case INT8OID:
+			value->type = jbvNumeric;
+			value->val.numeric = DatumGetNumeric(DirectFunctionCall1(int8_numeric, datum));
+			break;
+
+		case INT2OID:
+			value->type = jbvNumeric;
+			value->val.numeric = DatumGetNumeric(DirectFunctionCall1(int2_numeric, datum));
+			break;
+
+		case INT4OID:
+			value->type = jbvNumeric;
+			value->val.numeric = DatumGetNumeric(DirectFunctionCall1(int4_numeric, datum));
+			break;
+
+		case NUMERICOID:
+			value->type = jbvNumeric;
+			value->val.numeric = DatumGetNumeric(datum);
+			break;
+
+		default:
+			getTypeOutputInfo(typeid, &typeOut, &isvarlena);
+			str = OidOutputFunctionCall(typeOut, datum);
+			value->type = jbvString;
+			value->val.string.val = str;
+			value->val.string.len = strlen(str);
+			break;
+	}
+}
+
 void
 ts_jsonb_add_int32(JsonbParseState *state, const char *key, const int32 int_value)
 {

src/jsonb_utils.h

@@ -23,6 +23,7 @@ extern TSDLLEXPORT void ts_jsonb_add_int64(JsonbParseState *state, const char *k
 										   const int64 value);
 extern TSDLLEXPORT void ts_jsonb_add_numeric(JsonbParseState *state, const char *key,
 											 const Numeric value);
+extern TSDLLEXPORT void ts_jsonb_set_value_by_type(JsonbValue *value, Oid typeid, Datum datum);
 
 extern void ts_jsonb_add_value(JsonbParseState *state, const char *key, JsonbValue *value);
 

src/telemetry/telemetry.c

@@ -757,6 +757,93 @@ add_replication_telemetry(JsonbParseState *state)
 #define REQ_RELS_CONTINUOUS_AGGS "continuous_aggregates"
 #define REQ_FUNCTIONS_USED "functions_used"
 #define REQ_REPLICATION "replication"
+#define REQ_ACCESS_METHODS "access_methods"
+
+/*
+ * Add the result of a query as a sub-object to the JSONB.
+ *
+ * Each row from the query generates a separate object keyed by one of the
+ * columns. Each row will be represented as an object and stored under the
+ * "key" column. For example, with this query:
+ *
+ *    select amname as name,
+ *           sum(relpages) as pages,
+ *			 count(*) as instances
+ *		from pg_class join pg_am on relam = pg_am.oid
+ *	  group by pg_am.oid;
+ *
+ * might generate the object
+ *
+ * {
+ *    "brin" : {
+ *       "instances" : 44,
+ *       "pages" : 432
+ *    },
+ *    "btree" : {
+ *       "instances" : 99,
+ *       "pages" : 1234
+ *    }
+ * }
+ */
+static void
+add_query_result_dict(JsonbParseState *state, const char *query)
+{
+	MemoryContext orig_context = CurrentMemoryContext;
+
+	int res;
+	if (SPI_connect() != SPI_OK_CONNECT)
+		elog(ERROR, "could not connect to SPI");
+
+	/* Lock down search_path */
+	res = SPI_execute("SET LOCAL search_path TO pg_catalog, pg_temp", false, 0);
+	Ensure(res >= 0, "could not set search path");
+
+	res = SPI_execute(query, true, 0);
+	Ensure(res >= 0, "could not execute query");
+
+	MemoryContext spi_context = MemoryContextSwitchTo(orig_context);
+
+	(void) pushJsonbValue(&state, WJB_BEGIN_OBJECT, NULL);
+	for (uint64 r = 0; r < SPI_processed; r++)
+	{
+		char *key_string = SPI_getvalue(SPI_tuptable->vals[r], SPI_tuptable->tupdesc, 1);
+		JsonbValue key = {
+			.type = jbvString,
+			.val.string.val = pstrdup(key_string),
+			.val.string.len = strlen(key_string),
+		};
+
+		(void) pushJsonbValue(&state, WJB_KEY, &key);
+
+		(void) pushJsonbValue(&state, WJB_BEGIN_OBJECT, NULL);
+		for (int c = 1; c < SPI_tuptable->tupdesc->natts; ++c)
+		{
+			bool isnull;
+			Datum val_datum =
+				SPI_getbinval(SPI_tuptable->vals[r], SPI_tuptable->tupdesc, c + 1, &isnull);
+			if (!isnull)
+			{
+				char *key_string = SPI_fname(SPI_tuptable->tupdesc, c + 1);
+				JsonbValue key = {
+					.type = jbvString,
+					.val.string.val = pstrdup(key_string),
+					.val.string.len = strlen(key_string),
+				};
+				JsonbValue value;
+				ts_jsonb_set_value_by_type(&value,
+										   SPI_gettypeid(SPI_tuptable->tupdesc, c + 1),
+										   val_datum);
+				(void) pushJsonbValue(&state, WJB_KEY, &key);
+				(void) pushJsonbValue(&state, WJB_VALUE, &value);
+			}
+		}
+		pushJsonbValue(&state, WJB_END_OBJECT, NULL);
+	}
+	MemoryContextSwitchTo(spi_context);
+	res = SPI_finish();
+	Assert(res == SPI_OK_FINISH);
+	(void) pushJsonbValue(&state, WJB_END_OBJECT, NULL);
+}
 
 static Jsonb *
 build_telemetry_report()
@@ -937,6 +1024,15 @@ build_telemetry_report()
 	add_replication_telemetry(parse_state);
 	pushJsonbValue(&parse_state, WJB_END_OBJECT, NULL);
 
+	key.type = jbvString;
+	key.val.string.val = REQ_ACCESS_METHODS;
+	key.val.string.len = strlen(REQ_ACCESS_METHODS);
+	(void) pushJsonbValue(&parse_state, WJB_KEY, &key);
+	add_query_result_dict(parse_state,
+						  "SELECT amname AS name, sum(relpages) AS pages, count(*) AS "
+						  "instances FROM pg_class JOIN pg_am ON relam = pg_am.oid "
+						  "GROUP BY amname");
+
 	/* end of telemetry object */
 	result = pushJsonbValue(&parse_state, WJB_END_OBJECT, NULL);
 

test/expected/telemetry.out

@@ -350,6 +350,7 @@ WHERE key != 'os_name_pretty';
  db_metadata
  replication
  build_os_name
+ access_methods
  functions_used
  install_method
  installed_time
@@ -377,7 +378,7 @@ WHERE key != 'os_name_pretty';
  num_compression_policies_fixed
  num_user_defined_actions_fixed
  num_continuous_aggs_policies_fixed
-(37 rows)
+(38 rows)
 
 CREATE MATERIALIZED VIEW telemetry_report AS
 SELECT t FROM get_telemetry_report() t;
@@ -395,6 +396,17 @@ SELECT t -> 'instance_metadata' FROM telemetry_report;
  {"cloud": "ci"}
 (1 row)
 
+-- Check access methods
+SELECT t->'access_methods' ? 'btree',
+       t->'access_methods' ? 'heap',
+       CAST(t->'access_methods'->'btree'->'pages' AS int) > 0,
+       CAST(t->'access_methods'->'btree'->'instances' AS int) > 0
+  FROM telemetry_report;
+ ?column? | ?column? | ?column? | ?column? 
+----------+----------+----------+----------
+ t        | t        | t        | t
+(1 row)
+
 WITH t AS (
 	 SELECT t -> 'relations' AS rels
 	 FROM telemetry_report

test/sql/telemetry.sql

@@ -166,6 +166,13 @@ SELECT t -> 'db_metadata' FROM telemetry_report;
 -- check timescaledb_telemetry.cloud
 SELECT t -> 'instance_metadata' FROM telemetry_report;
 
+-- Check access methods
+SELECT t->'access_methods' ? 'btree',
+       t->'access_methods' ? 'heap',
+       CAST(t->'access_methods'->'btree'->'pages' AS int) > 0,
+       CAST(t->'access_methods'->'btree'->'instances' AS int) > 0
+  FROM telemetry_report;
+
 WITH t AS (
 	 SELECT t -> 'relations' AS rels
 	 FROM telemetry_report