fluencelabs/redis
1
0
Fork 0
mirror of https://github.com/fluencelabs/redis synced 2025-06-15 02:01:21 +00:00
Code Issues Projects Releases Wiki Activity

PSYNC2: stop sending newlines to sub-slaves when master is down.

Browse Source 
This actually includes two changes:

1) No newlines to take the master-slave link up when the upstream master
is down. Doing this is dangerous because the sub-slave often is received
replication protocol for an half-command, so can't receive newlines
without desyncing the replication link, even with the code in order to
cancel out the bytes that PSYNC2 was using. Moreover this is probably
also not needed/sane, because anyway the slave can keep serving
requests, and because if it's configured to don't serve stale data, it's
a good idea, actually, to break the link.

2) When a +CONTINUE with a different ID is received, we now break
connection with the sub-slaves: they need to be notified as well. This
was part of the original specification but for some reason it was not
implemented in the code, and was alter found as a PSYNC2 bug in the
integration testing.
This commit is contained in:
antirez
2016-11-28 17:54:04 +01:00
parent 16559a02fc
commit eab865a0a1
3 changed files with 6 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
src/replication.c
View File

@ -148,22 +148,6 @@ void feedReplicationBacklog(void *ptr, size_t len) {
server.repl_backlog_histlen + 1;
}
/* Remove the last byte from the replication backlog. This
* is useful when we receive an out of band "\n" to keep the connection
* alive but don't want to count it as replication stream.
*
* As a side effect this function adjusts the master replication offset
* of this instance to account for the missing byte. */
void chopReplicationBacklog(void) {
if (!server.repl_backlog || !server.repl_backlog_histlen) return;
if (server.repl_backlog_idx == 0)
server.repl_backlog_idx = server.repl_backlog_size-1;
else
server.repl_backlog_idx--;
server.master_repl_offset--;
server.repl_backlog_histlen--;
}
/* Wrapper for feedReplicationBacklog() that takes Redis string objects
* as input. */
void feedReplicationBacklogWithObject(robj *o) {
@ -1530,6 +1514,9 @@ int slaveTryPartialResynchronization(int fd, int read_reply) {
* new one. */
memcpy(server.replid,new,sizeof(server.replid));
memcpy(server.cached_master->replid,new,sizeof(server.replid));
/* Disconnect all the sub-slaves: they need to be notified. */
disconnectSlaves();
}
}
@ -2553,10 +2540,8 @@ void replicationCron(void) {
(slave->replstate == SLAVE_STATE_WAIT_BGSAVE_START ||
(slave->replstate == SLAVE_STATE_WAIT_BGSAVE_END &&
server.rdb_child_type != RDB_CHILD_TYPE_SOCKET));
int is_subslave = server.masterhost && server.master == NULL &&
slave->replstate == SLAVE_STATE_ONLINE;
if (is_presync || is_subslave) {
if (is_presync) {
if (write(slave->fd, "\n", 1) == -1) {
/* Don't worry about socket errors, it's just a ping. */
}