了解一下数据库存储的数据，有助于排查问题。
概览
sonic-py-swsssdk/src/swsssdk/config/database.json记录了几个数据类型，另外sonic-swss-common/common/schema.h记录的更为全面一些，我们查看一下：
#define APPL_DB 0
#define ASIC_DB 1
#define COUNTERS_DB 2
#define LOGLEVEL_DB 3
#define CONFIG_DB 4
#define PFC_WD_DB 5
#define FLEX_COUNTER_DB 5
#define STATE_DB 6APPL_DB
#define APP_PORT_TABLE_NAME "PORT_TABLE" //记录了Ethernet端口，内含端口名称，index，端口状态，MTU和speed
#define APP_VLAN_TABLE_NAME "VLAN_TABLE" //记录了VLAN信息，只包含了配置状态
#define APP_VLAN_MEMBER_TABLE_NAME "VLAN_MEMBER_TABLE" //记录了端口和VLAN的对应关系，内含tag状态(tagged类似trunk，untagged类似access)
#define APP_LAG_TABLE_NAME "LAG_TABLE" //记录了LAG端口，内含端口状态和MTU
#define APP_LAG_MEMBER_TABLE_NAME "LAG_MEMBER_TABLE" //记录了端口和LAG的对应关系，内含配置状态
#define APP_INTF_TABLE_NAME "INTF_TABLE" //记录了端口的IP地址，内含协议族类型和范围
#define APP_NEIGH_TABLE_NAME "NEIGH_TABLE" //记录了neighbor的IP地址，内含协议族和neigbor的mac地址
#define APP_ROUTE_TABLE_NAME "ROUTE_TABLE" //记录了路由IP，内含端口名称以及下一跳信息
#define APP_TUNNEL_DECAP_TABLE_NAME "TUNNEL_DECAP_TABLE" //记录了tunnel信息
#define APP_MIRROR_SESSION_TABLE_NAME "MIRROR_SESSION" //记录了mirror信息
#define APP_FDB_TABLE_NAME "FDB_TABLE"
#define APP_PFC_WD_TABLE_NAME "PFC_WD_TABLE"
#define APP_SWITCH_TABLE_NAME "SWITCH_TABLE"
#define APP_COPP_TABLE_NAME "COPP_TABLE"ASIC_DB
sonic-sairedis/lib/inc/sairedis.h
#define ASIC_STATE_TABLE "ASIC_STATE"后面跟着如下内容。
sonic-sairedis/SAI/inc/saitypes.h
SAI_OBJECT_TYPE_NULL = 0, //invalid object type
SAI_OBJECT_TYPE_PORT = 1, //端口ID，内含状态，MTU，priority，speed等
SAI_OBJECT_TYPE_LAG = 2, //LAG端口ID，内含ACL信息
SAI_OBJECT_TYPE_VIRTUAL_ROUTER = 3, //虚拟路由
SAI_OBJECT_TYPE_NEXT_HOP = 4, //下一跳信息，内含IP，端口ID，类型
SAI_OBJECT_TYPE_NEXT_HOP_GROUP = 5, //下一跳的组的信息，内含类型，比如ECMP
SAI_OBJECT_TYPE_ROUTER_INTERFACE = 6, //路由信息，内含MTU，端口ID，源MAC，类型，router id等
SAI_OBJECT_TYPE_ACL_TABLE = 7, //ACL表配置信息
SAI_OBJECT_TYPE_ACL_ENTRY = 8, //ACL表项信息，内含ACL三色，DSCP，ECN，priority，table id等
SAI_OBJECT_TYPE_ACL_COUNTER = 9,
SAI_OBJECT_TYPE_ACL_RANGE = 10,
SAI_OBJECT_TYPE_ACL_TABLE_GROUP = 11, //ACL Table Group，内含ACL Stage和类型
SAI_OBJECT_TYPE_ACL_TABLE_GROUP_MEMBER = 12, //ACL Table Group Member，内含ACL Table id和ACL Table Group id
SAI_OBJECT_TYPE_HOSTIF = 13, //主机端口，内含name，status，type，tag
SAI_OBJECT_TYPE_MIRROR_SESSION = 14,
SAI_OBJECT_TYPE_SAMPLEPACKET = 15,
SAI_OBJECT_TYPE_STP = 16,
SAI_OBJECT_TYPE_HOSTIF_TRAP_GROUP = 17,
SAI_OBJECT_TYPE_POLICER = 18, //策略配置信息，内含cbs，cir，mode等信息
SAI_OBJECT_TYPE_WRED = 19, //WRED信息配置
SAI_OBJECT_TYPE_QOS_MAP = 20, //QoS映射信息
SAI_OBJECT_TYPE_QUEUE = 21, //Queue信息，没看到啥东西
SAI_OBJECT_TYPE_SCHEDULER = 22, //调度，内含调度类型和weight
SAI_OBJECT_TYPE_SCHEDULER_GROUP = 23, //调度组，内含包含的调度
SAI_OBJECT_TYPE_BUFFER_POOL = 24, //pool的大小，threshold，type
SAI_OBJECT_TYPE_BUFFER_PROFILE = 25, //pool的id，reserved size
SAI_OBJECT_TYPE_INGRESS_PRIORITY_GROUP = 26, //包含了buffer profile的id
SAI_OBJECT_TYPE_LAG_MEMBER = 27, //LAG id和Port id
SAI_OBJECT_TYPE_HASH = 28,
SAI_OBJECT_TYPE_UDF = 29,
SAI_OBJECT_TYPE_UDF_MATCH = 30,
SAI_OBJECT_TYPE_UDF_GROUP = 31,
SAI_OBJECT_TYPE_FDB_ENTRY = 32, //FDB表，内含mac，switch_id，port_id，action，type
SAI_OBJECT_TYPE_SWITCH = 33, //switch信息，内含hash seed，notify，LAG hash seed，mac
SAI_OBJECT_TYPE_HOSTIF_TRAP = 34, //内含action，group，type
SAI_OBJECT_TYPE_HOSTIF_TABLE_ENTRY = 35,
SAI_OBJECT_TYPE_NEIGHBOR_ENTRY = 36, //邻居信息，ip，mac
SAI_OBJECT_TYPE_ROUTE_ENTRY = 37, //路由信息，dest ip，next hop id，action
SAI_OBJECT_TYPE_VLAN = 38, //Vlan信息，主要是vid
SAI_OBJECT_TYPE_VLAN_MEMBER = 39, //vlan id和tagging mode
SAI_OBJECT_TYPE_HOSTIF_PACKET = 40,
SAI_OBJECT_TYPE_TUNNEL_MAP = 41,
SAI_OBJECT_TYPE_TUNNEL = 42, //tunnel信息，内含不少信息
SAI_OBJECT_TYPE_TUNNEL_TERM_TABLE_ENTRY = 43,
SAI_OBJECT_TYPE_FDB_FLUSH = 44,
SAI_OBJECT_TYPE_NEXT_HOP_GROUP_MEMBER = 45, //next hop信息
SAI_OBJECT_TYPE_STP_PORT = 46,
SAI_OBJECT_TYPE_RPF_GROUP = 47,
SAI_OBJECT_TYPE_RPF_GROUP_MEMBER = 48,
SAI_OBJECT_TYPE_L2MC_GROUP = 49,
SAI_OBJECT_TYPE_L2MC_GROUP_MEMBER = 50,
SAI_OBJECT_TYPE_IPMC_GROUP = 51,
SAI_OBJECT_TYPE_IPMC_GROUP_MEMBER = 52,
SAI_OBJECT_TYPE_L2MC_ENTRY = 53,
SAI_OBJECT_TYPE_IPMC_ENTRY = 54,
SAI_OBJECT_TYPE_MCAST_FDB_ENTRY = 55,
SAI_OBJECT_TYPE_HOSTIF_USER_DEFINED_TRAP = 56,
SAI_OBJECT_TYPE_BRIDGE = 57,
SAI_OBJECT_TYPE_BRIDGE_PORT = 58, //端口状态，端口id，类型
SAI_OBJECT_TYPE_TUNNEL_MAP_ENTRY = 59,
SAI_OBJECT_TYPE_TAM = 60,
SAI_OBJECT_TYPE_TAM_STAT = 61,
SAI_OBJECT_TYPE_TAM_SNAPSHOT = 62,
SAI_OBJECT_TYPE_TAM_TRANSPORTER = 63,
SAI_OBJECT_TYPE_TAM_THRESHOLD = 64,
SAI_OBJECT_TYPE_SEGMENTROUTE_SIDLIST = 65,
SAI_OBJECT_TYPE_PORT_POOL = 66,
SAI_OBJECT_TYPE_INSEG_ENTRY = 67,
SAI_OBJECT_TYPE_TAM_HISTOGRAM = 68,
SAI_OBJECT_TYPE_TAM_MICROBURST = 69,
SAI_OBJECT_TYPE_DTEL = 70, /**< experimental */
SAI_OBJECT_TYPE_DTEL_QUEUE_REPORT = 71, /**< experimental */
SAI_OBJECT_TYPE_DTEL_INT_SESSION = 72, /**< experimental */
SAI_OBJECT_TYPE_DTEL_REPORT_SESSION = 73, /**< experimental */
SAI_OBJECT_TYPE_DTEL_EVENT = 74, /**< experimental */
SAI_OBJECT_TYPE_BFD_SESSION = 75,
SAI_OBJECT_TYPE_MAX = 76,COUNTERS_DB
#define COUNTERS_PORT_NAME_MAP "COUNTERS_PORT_NAME_MAP" //端口名字和ID的映射关系
#define COUNTERS_TABLE "COUNTERS" //端口ID和对应的端口统计信息
#define COUNTERS_QUEUE_NAME_MAP "COUNTERS_QUEUE_NAME_MAP" //端口名字队列和ID的映射关系
#define COUNTERS_QUEUE_PORT_MAP "COUNTERS_QUEUE_PORT_MAP" //端口ID和队列ID的对应关系
#define COUNTERS_QUEUE_INDEX_MAP "COUNTERS_QUEUE_INDEX_MAP" //队列id和端口队列index的对应关系
#define COUNTERS_QUEUE_TYPE_MAP "COUNTERS_QUEUE_TYPE_MAP" //队列id和类型的对应关系，单播多播之类的
#define COUNTERS_CRM_TABLE "CRM"LOGLEVEL_DB
#define DAEMON_TABLE_NAME "DAEMON_TABLE"
#define DAEMON_LOGLEVEL "LOGLEVEL"
#define DAEMON_LOGOUTPUT "LOGOUTPUT"CONFIG_DB
#define CFG_PORT_TABLE_NAME "PORT" //端口信息，内含名称，lanes和speed
#define CFG_PORT_CABLE_LEN_TABLE_NAME "CABLE_LENGTH" //端口支持的线长度
#define CFG_INTF_TABLE_NAME "INTERFACE" //端口信息，主要是端口名称和ip
#define CFG_LOOPBACK_INTERFACE_TABLE_NAME "LOOPBACK_INTERFACE" //loopback端口，和上面一样
#define CFG_MGMT_INTERFACE_TABLE_NAME "MGMT_INTERFACE" //管理端口，和上面一样
#define CFG_LAG_INTF_TABLE_NAME "PORTCHANNEL_INTERFACE" //portchannel端口，
#define CFG_VLAN_INTF_TABLE_NAME "VLAN_INTERFACE" //VLAN端口
#define CFG_LAG_TABLE_NAME "PORTCHANNEL" //主要记录了portchannel中包含的端口
#define CFG_VLAN_TABLE_NAME "VLAN" //主要记录了vlan id
#define CFG_VLAN_MEMBER_TABLE_NAME "VLAN_MEMBER" //主要记录了vlan包含的端口
#define CFG_SWITCH_TABLE_NAME "SWITCH"
#define CFG_VRF_TABLE_NAME "VRF"
#define CFG_CRM_TABLE_NAME "CRM"
#define CFG_VXLAN_TUNNEL_DECAP_TABLE_NAME "VXLAN_TUNNEL_DECAP"
#define CFG_DHCP_SERVER_TABLE_NAME "DHCP_SERVER" //以下记录了几个server的ip
#define CFG_NTP_SERVER_TABLE_NAME "NTP_SERVER"
#define CFG_SYSLOG_SERVER_TABLE_NAME "SYSLOG_SERVER"
#define CFG_BGP_NEIGHBOR_TABLE_NAME "BGP_NEIGHBOR" //内含ip，端口状态，asn，holdtime，keepalive，本地ip，name等
#define CFG_DEVICE_METADATA_TABLE_NAME "DEVICE_METADATA" //貌似也是和bgp相关的
#define CFG_DEVICE_NEIGHBOR_TABLE_NAME "DEVICE_NEIGHBOR"
#define CFG_DEVICE_NEIGHBOR_METADATA_TABLE_NAME "DEVICE_NEIGHBOR_METADATA"
#define CFG_MIRROR_SESSION_TABLE_NAME "MIRROR_SESSION" //内含源、目的IP
#define CFG_ACL_TABLE_NAME "ACL_TABLE"
#define CFG_ACL_RULE_TABLE_NAME "ACL_RULE"
#define CFG_PFC_WD_TABLE_NAME "PFC_WD_TABLE"
#define CFG_FLEX_COUNTER_TABLE_NAME "FLEX_COUNTER_TABLE"
#define CFG_PFC_PRIORITY_TO_PRIORITY_GROUP_MAP_TABLE_NAME "PFC_PRIORITY_TO_PRIORITY_GROUP_MAP"
#define CFG_TC_TO_PRIORITY_GROUP_MAP_TABLE_NAME "TC_TO_PRIORITY_GROUP_MAP"
#define CFG_PFC_PRIORITY_TO_QUEUE_MAP_TABLE_NAME "MAP_PFC_PRIORITY_TO_QUEUE"
#define CFG_TC_TO_QUEUE_MAP_TABLE_NAME "TC_TO_QUEUE_MAP"
#define CFG_DSCP_TO_TC_MAP_TABLE_NAME "DSCP_TO_TC_MAP"
#define CFG_SCHEDULER_TABLE_NAME "SCHEDULER"
#define CFG_PORT_QOS_MAP_TABLE_NAME "PORT_QOS_MAP"
#define CFG_WRED_PROFILE_TABLE_NAME "WRED_PROFILE"
#define CFG_QUEUE_TABLE_NAME "QUEUE"
#define CFG_BUFFER_POOL_TABLE_NAME "BUFFER_POOL"
#define CFG_BUFFER_PROFILE_TABLE_NAME "BUFFER_PROFILE"
#define CFG_BUFFER_QUEUE_TABLE_NAME "BUFFER_QUEUE"
#define CFG_BUFFER_PG_TABLE_NAME "BUFFER_PG"
#define CFG_BUFFER_PORT_INGRESS_PROFILE_LIST_NAME "BUFFER_PORT_INGRESS_PROFILE_LIST"
#define CFG_BUFFER_PORT_EGRESS_PROFILE_LIST_NAME "BUFFER_PORT_EGRESS_PROFILE_LIST"PFC_WD_DB
FLEX_COUNTER_DB
#define PFC_WD_POLL_MSECS 100
#define FLEX_COUNTER_TABLE "FLEX_COUNTER_TABLE"
#define PORT_COUNTER_ID_LIST "PORT_COUNTER_ID_LIST"
#define QUEUE_COUNTER_ID_LIST "QUEUE_COUNTER_ID_LIST"
#define QUEUE_ATTR_ID_LIST "QUEUE_ATTR_ID_LIST"
#define PFC_WD_STATE_TABLE "PFC_WD_STATE_TABLE"
#define PFC_WD_PORT_COUNTER_ID_LIST "PORT_COUNTER_ID_LIST"
#define PFC_WD_QUEUE_COUNTER_ID_LIST "QUEUE_COUNTER_ID_LIST"
#define PFC_WD_QUEUE_ATTR_ID_LIST "QUEUE_ATTR_ID_LIST"
#define PLUGIN_TABLE "PLUGIN_TABLE"
#define LUA_PLUGIN_TYPE "LUA_PLUGIN_TYPE"
#define SAI_OBJECT_TYPE "SAI_OBJECT_TYPE"
#define POLL_INTERVAL_FIELD "POLL_INTERVAL"
#define QUEUE_PLUGIN_FIELD "QUEUE_PLUGIN_LIST"
#define PORT_PLUGIN_FIELD "PORT_PLUGIN_LIT"
#define FLEX_COUNTER_STATUS_FIELD "FLEX_COUNTER_STATUS"
#define FLEX_COUNTER_GROUP_TABLE "FLEX_COUNTER_GROUP_TABLE"STATE_DB
#define STATE_PORT_TABLE_NAME "PORT_TABLE" //记录端口的状态
#define STATE_LAG_TABLE_NAME "LAG_TABLE" //LAG状态
#define STATE_VLAN_TABLE_NAME "VLAN_TABLE" //VLAN状态
#define STATE_VLAN_MEMBER_TABLE_NAME "VLAN_MEMBER_TABLE"
#define STATE_INTERFACE_TABLE_NAME "INTERFACE_TABLE"