Function UpdateIdIndexToSetStatsState

pg_documentdb/src/metadata/index.c:3146–3236

static void
UpdateIdIndexToSetStatsState(uint64 collectionId, bool enableStats)
{
	StringInfoData queryStringInfo;
	initStringInfo(&queryStringInfo);

	appendStringInfo(&queryStringInfo,
					 "SELECT index_id, index_spec FROM %s.collection_indexes"
					 " WHERE collection_id = %lu AND (index_spec).index_name = '_id_' LIMIT 1 FOR UPDATE",
					 ApiCatalogSchemaName, collectionId);

	/* all args are non-null */
	bool readOnly = false;
	int numValues = 2;
	bool isNull[2];
	Datum results[2];
	ExtensionExecuteMultiValueQueryViaSPI(queryStringInfo.data, readOnly,
										  SPI_OK_SELECT, results, isNull,
										  numValues);

	if (isNull[0] || isNull[1])
	{
		ereport(ERROR, (errmsg(
							"Could not find primary key index for collection. This is unexpected")));
	}

	IndexDetails indexDetails = { 0 };
	indexDetails.indexId = DatumGetInt32(results[0]);
	indexDetails.indexSpec = *DatumGetIndexSpec(results[1]);
	indexDetails.collectionId = collectionId;

	pgbson *indexOptions = indexDetails.indexSpec.indexOptions;
	if (indexOptions == NULL)
	{
		indexOptions = PgbsonInitEmpty();
	}

	bson_iter_t iter;
	pgbson_writer optionsWriter;
	PgbsonWriterInit(&optionsWriter);
	PgbsonInitIterator(indexOptions, &iter);
	bool foundStatsEnabled = false;
	while (bson_iter_next(&iter))
	{
		const char *key = bson_iter_key(&iter);
		const bson_value_t *value = bson_iter_value(&iter);
		if (strcmp(key, "statsEnabled") == 0)
		{
			foundStatsEnabled = true;

			/* Skip writing the field if it's false (disabled) */
			if (enableStats)
			{
				PgbsonWriterAppendBool(&optionsWriter, key, -1, true);
			}
		}
		else
		{