Shulou(Shulou.com)06/01 Report--

WaitForWALToBecomeAvailable: if (! InArchiveRecovery) currentSource = XLOG_FROM_PG_WAL; else if (currentSource = = 0) currentSource = XLOG_FROM_ARCHIVE; for (;;) {int oldSource = currentSource If (lastSourceFailed) {switch (currentSource) {case XLOG_FROM_ARCHIVE: case XLOG_FROM_PG_WAL:// if it is a standby and promote is executed or the TriggerFile file exists, then the shutdown receive process if (StandbyMode & & CheckForStandbyTrigger ()) {ShutdownWalRcv (); return false } if (! StandbyMode) return false / * the site of the build stream replication relationship: 1. If the last normal shutdown does not need to be restored, start from the checkpoint point 2, otherwise Start at the end of the restore * / if (PrimaryConnInfo) {if (fetching_ckpt) {ptr = RedoStartLSN Tli = ControlFile- > checkPointCopy.ThisTimeLineID;} else {ptr = RecPtr; tli = tliOfPointInHistory (tliRecPtr, expectedTLEs);} curFileTLI = tli; RequestXLogStreaming (tli, ptr, PrimaryConnInfo, PrimarySlotName) ReceivedUpto = 0;} currentSource = XLOG_FROM_STREAM; break .}}.} / * 1. The starting position of the stream copy pull log is at the beginning of the file where the site is located. 2, that is, the entire xlog file will be pulled again and the corresponding file of the pg_xlog directory will be overwritten. 3. Therefore, when starting with the main shutdown and standby again, you need to pay attention. Will pull the corresponding file from the new master and 4, overwrite the local file, but the local pg_control file has not been updated, so the read checkpoint location will point to a wrong location 5. In this case, build stream replication requires careful attention. * / RequestXLogStreaming: if (recptr% XLogSegSize! = 0) recptr-= recptr% XLogSegSize; walrcv- > receiveStart = recptr; walrcv- > receiveStartTLI = tli; SendPostmasterSignal (PMSIGNAL_START_WALRECEIVER); / / initiate a signal to wake up the receiver process

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