typedef enum PortalStrategy {    PORTAL_ONE_SELECT, // SQL语句包含单一的SELECT查询    PORTAL_ONE_RETURNING, // INSERT/UPDATE/DELETE语句包含Returning    PORTAL_ONE_MOD_WITH, // 查询语句包含With    PORTAL_UTIL_SELECT, // 工具类型查询语句，如explain    PORTAL_MULTI_QUERY // 所有其他类型查询语句} PortalStrategy;

bool PortalRun(    Portal portal, long count, bool isTopLevel, DestReceiver* dest, DestReceiver* altdest, char* completionTag){        …        switch (portal->strategy) {            case PORTAL_ONE_SELECT:                …            case PORTAL_MULTI_QUERY: // insert从这里进入                PortalRunMulti(portal, isTopLevel, dest, altdest, completionTag);                 /* Prevent portal's commands from being re-executed */                MarkPortalDone(portal);                /* Always complete at end of RunMulti */                result = true;                break;    …}