接前文:初步学习pg_control文件之五 ,DB_IN_ARCHIVE_RECOVERY何时出现?
看代码:如果recovery.conf文件存在,则返回 InArchiveRecovery = true。
/* * See if there is a recovery command file (recovery.conf), and if so * read in parameters for archive recovery and XLOG streaming. * The file is parsed using the main configuration parser. */ static void readRecoveryCommandFile(void) { … fd = AllocateFile(RECOVERY_COMMAND_FILE, "r"); if (fd == NULL) { if (errno == ENOENT) return; /* not there, so no archive recovery */ ereport(FATAL, (errcode_for_file_access(), errmsg("could not open recovery command file \"%s\": %m", RECOVERY_COMMAND_FILE))); } … /* Enable fetching from archive recovery area */ InArchiveRecovery = true; … }
然后,如果pg_control文件的state不是 DB_SHUTDOWNED状态,则可以认为需要recovery,
此时,如果 InArchiveRecovery 为true,则开始设置DB_IN_ARCHIVE_RECOVERY 状态。
/* * This must be called ONCE during postmaster or standalone-backend startup */ void StartupXLOG(void) { … /* * Check for recovery control file, and if so set up state for offline * recovery */ readRecoveryCommandFile(); … /* * Check whether we need to force recovery from WAL. If it appears to * have been a clean shutdown and we did not have a recovery.conf file, * then assume no recovery needed. */ if (XLByteLT(checkPoint.redo, RecPtr)) { if (wasShutdown) ereport(PANIC, (errmsg("invalid redo record in shutdown checkpoint"))); InRecovery = true; } else if (ControlFile->state != DB_SHUTDOWNED) InRecovery = true; else if (InArchiveRecovery) { /* force recovery due to presence of recovery.conf */ InRecovery = true; } /* REDO */ if (InRecovery) { int rmid; /* use volatile pointer to prevent code rearrangement */ volatile XLogCtlData *xlogctl = XLogCtl; /* * Update pg_control to show that we are recovering and to show the * selected checkpoint as the place we are starting from. We also mark * pg_control with any minimum recovery stop point obtained from a * backup history file. */ if (InArchiveRecovery) ControlFile->state = DB_IN_ARCHIVE_RECOVERY; else { ereport(LOG, (errmsg("database system was not properly shut down; " automatic recovery in progress))); ControlFile->state = DB_IN_CRASH_RECOVERY; } … UpdateControlFile(); … } … }