WalReceiver进程的描述结构WalRcvData，仅当作记录
代码语言：javascript复制typedef struct
{
pid_t pid;//当前walreciver进程的pid
WalRcvState walRcvState;//标记进程状态
pg_time_t startTime;//RequestXLogStream函数调用的开始时间
//startup进程第一次启动walreceiver进程时，是流复制需要的开始位置
XLogRecPtr receiveStart;//拉取日志的起始位置，文件对齐了，也就是从段文件头开始
TimeLineID receiveStartTLI;//拉取日志的时间线
/*receiver进程第一次启动时，设置为receiveStart和receiveStartTLI，后续每次接收的日志刷盘时更新*/
XLogRecPtr receivedUpto;
TimeLineID receivedTLI;
//第一次启动时，拉取日志的起始位置
XLogRecPtr latestChunkStart;
/*
* Time of send and receive of any message received.
*/
TimestampTz lastMsgSendTime;
TimestampTz lastMsgReceiptTime;
/*
* Latest reported end of WAL on the sender
*/
XLogRecPtr latestWalEnd;
TimestampTz latestWalEndTime;
//连接信息：PrimaryConnInfo<---primary_conninfo
char conninfo[MAXCONNINFO];
/*
* Host name (this can be a host name, an IP address, or a directory path)
* and port number of the active replication connection.
*/
char sender_host[NI_MAXHOST];
int sender_port;
//复制槽名：PrimarySlotName <--- primary_slot_name
char slotname[NAMEDATALEN];
/* set true once conninfo is ready to display (obfuscated pwds etc) */
bool ready_to_display;
/*
* Latch used by startup process to wake up walreceiver after telling it
* where to start streaming (after setting receiveStart and
* receiveStartTLI), and also to tell it to send apply feedback to the
* primary whenever specially marked commit records are applied. This is
* normally mapped to procLatch when walreceiver is running.
*/
Latch *latch;
slock_t mutex; /* locks shared variables shown above */
/*
* force walreceiver reply? This doesn't need to be locked; memory
* barriers for ordering are sufficient. But we do need atomic fetch and
* store semantics, so use sig_atomic_t.
*/
sig_atomic_t force_reply; /* used as a bool */
}
typedef enum
{
WALRCV_STOPPED, /* stopped and mustn't start up again */
WALRCV_STARTING, /* launched, but the process hasn't
* initialized yet */
WALRCV_STREAMING, /* walreceiver is streaming */
WALRCV_WAITING, /* stopped streaming, waiting for orders */
WALRCV_RESTARTING, /* asked to restart streaming */
WALRCV_STOPPING /* requested to stop, but still running */
} WalRcvState;
