diff options
Diffstat (limited to 'src/backend/access/transam/xlogfuncs.c')
| -rw-r--r-- | src/backend/access/transam/xlogfuncs.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c index 97317429786..a31adcca5eb 100644 --- a/src/backend/access/transam/xlogfuncs.c +++ b/src/backend/access/transam/xlogfuncs.c @@ -16,6 +16,8 @@ */ #include "postgres.h" +#include <unistd.h> + #include "access/htup_details.h" #include "access/xlog.h" #include "access/xlog_internal.h" @@ -23,6 +25,7 @@ #include "catalog/pg_type.h" #include "funcapi.h" #include "miscadmin.h" +#include "pgstat.h" #include "replication/walreceiver.h" #include "storage/smgr.h" #include "utils/builtins.h" @@ -697,3 +700,77 @@ pg_backup_start_time(PG_FUNCTION_ARGS) PG_RETURN_DATUM(xtime); } + +/* + * Promotes a standby server. + * + * A result of "true" means that promotion has been completed if "wait" is + * "true", or initiated if "wait" is false. + */ +Datum +pg_promote(PG_FUNCTION_ARGS) +{ + bool wait = PG_GETARG_BOOL(0); + int wait_seconds = PG_GETARG_INT32(1); + FILE *promote_file; + int i; + + if (!RecoveryInProgress()) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("recovery is not in progress"), + errhint("Recovery control functions can only be executed during recovery."))); + + if (wait_seconds <= 0) + ereport(ERROR, + (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE), + errmsg("\"wait_seconds\" cannot be negative or equal zero"))); + + /* create the promote signal file */ + promote_file = AllocateFile(PROMOTE_SIGNAL_FILE, "w"); + if (!promote_file) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not create file \"%s\": %m", + PROMOTE_SIGNAL_FILE))); + + if (FreeFile(promote_file)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write file \"%s\": %m", + PROMOTE_SIGNAL_FILE))); + + /* signal the postmaster */ + if (kill(PostmasterPid, SIGUSR1) != 0) + { + ereport(WARNING, + (errmsg("failed to send signal to postmaster: %m"))); + (void) unlink(PROMOTE_SIGNAL_FILE); + PG_RETURN_BOOL(false); + } + + /* return immediately if waiting was not requested */ + if (!wait) + PG_RETURN_BOOL(true); + + /* wait for the amount of time wanted until promotion */ +#define WAITS_PER_SECOND 10 + for (i = 0; i < WAITS_PER_SECOND * wait_seconds; i++) + { + ResetLatch(MyLatch); + + if (!RecoveryInProgress()) + PG_RETURN_BOOL(true); + + CHECK_FOR_INTERRUPTS(); + + WaitLatch(MyLatch, + WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH, + 1000L / WAITS_PER_SECOND, + WAIT_EVENT_PROMOTE); + } + + ereport(WARNING, + (errmsg("server did not promote within %d seconds", wait_seconds))); + PG_RETURN_BOOL(false); +} |