mirror of
https://github.com/fluencelabs/redis
synced 2025-03-18 16:40:50 +00:00
Force expire all timer events when system clock skew is detected.
When system time changes back, the timer will not worker properly hence some core functionality of redis will stop working(e.g. replication, bgsave, etc). See issue #633 for details. The patch saves the previous time and when a system clock skew is detected, it will force expire all timers. Modiifed by @antirez: the previous time was moved into the eventLoop structure to make sure the library is still thread safe as long as you use different event loops into different threads (otherwise you need some synchronization). More comments added about the reasoning at the base of the patch, that's worth reporting here: /* If the system clock is moved to the future, and then set back to the * right value, time events may be delayed in a random way. Often this * means that scheduled operations will not be performed soon enough. * * Here we try to detect system clock skews, and force all the time * events to be processed ASAP when this happens: the idea is that * processing events earlier is less dangerous than delaying them * indefinitely, and practice suggests it is. */
This commit is contained in:
parent
f0b9f80345
commit
b7b2a1cc5e
19
src/ae.c
19
src/ae.c
@ -67,6 +67,7 @@ aeEventLoop *aeCreateEventLoop(int setsize) {
|
||||
eventLoop->fired = zmalloc(sizeof(aeFiredEvent)*setsize);
|
||||
if (eventLoop->events == NULL || eventLoop->fired == NULL) goto err;
|
||||
eventLoop->setsize = setsize;
|
||||
eventLoop->lastTime = time(NULL);
|
||||
eventLoop->timeEventHead = NULL;
|
||||
eventLoop->timeEventNextId = 0;
|
||||
eventLoop->stop = 0;
|
||||
@ -236,6 +237,24 @@ static int processTimeEvents(aeEventLoop *eventLoop) {
|
||||
int processed = 0;
|
||||
aeTimeEvent *te;
|
||||
long long maxId;
|
||||
time_t now = time(NULL);
|
||||
|
||||
/* If the system clock is moved to the future, and then set back to the
|
||||
* right value, time events may be delayed in a random way. Often this
|
||||
* means that scheduled operations will not be performed soon enough.
|
||||
*
|
||||
* Here we try to detect system clock skews, and force all the time
|
||||
* events to be processed ASAP when this happens: the idea is that
|
||||
* processing events earlier is less dangerous than delaying them
|
||||
* indefinitely, and practice suggests it is. */
|
||||
if (now < eventLoop->lastTime) {
|
||||
te = eventLoop->timeEventHead;
|
||||
while(te) {
|
||||
te->when_sec = 0;
|
||||
te = te->next;
|
||||
}
|
||||
}
|
||||
eventLoop->lastTime = now;
|
||||
|
||||
te = eventLoop->timeEventHead;
|
||||
maxId = eventLoop->timeEventNextId-1;
|
||||
|
1
src/ae.h
1
src/ae.h
@ -88,6 +88,7 @@ typedef struct aeEventLoop {
|
||||
int maxfd; /* highest file descriptor currently registered */
|
||||
int setsize; /* max number of file descriptors tracked */
|
||||
long long timeEventNextId;
|
||||
time_t lastTime; /* Used to detect system clock skew */
|
||||
aeFileEvent *events; /* Registered events */
|
||||
aeFiredEvent *fired; /* Fired events */
|
||||
aeTimeEvent *timeEventHead;
|
||||
|
Loading…
x
Reference in New Issue
Block a user