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Diskless replication: parent-child pipe and a few TODOs.

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antirez
2014-10-14 15:29:07 +02:00
parent 30231ea005
commit eaeeb1216d
2 changed files with 35 additions and 4 deletions
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37
src/rdb.c
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@ -1274,7 +1274,13 @@ void backgroundSaveDoneHandlerDisk(int exitcode, int bysignal) {
/* A background saving child (BGSAVE) terminated its work. Handle this.
* This function covers the case of RDB -> Salves socket transfers for
* diskless replication. */
* diskless replication.
*
* TODO:
* 1) Read from the pipe the set of IDs which are fine. This should be
* just an uint32_t with the len, and N pid_t elements.
* 2) Close all the slaves in state REDIS_REPL_WAIT_BGSAVE_END but are
* not reported as "transfer ok" by the child. */
void backgroundSaveDoneHandlerSocket(int exitcode, int bysignal) {
if (!bysignal && exitcode == 0) {
redisLog(REDIS_NOTICE,
@ -1288,8 +1294,18 @@ void backgroundSaveDoneHandlerSocket(int exitcode, int bysignal) {
server.rdb_child_pid = -1;
server.rdb_child_type = REDIS_RDB_CHILD_TYPE_NONE;
server.rdb_save_time_start = -1;
/* Possibly there are slaves waiting for a BGSAVE in order to be served
* (the first stage of SYNC is a bulk transfer of dump.rdb) */
/* Read the set of slave client IDs that currently received the full
* RDB payload, closing all the slaves which are not among the ones
* listed. */
/* TODO ... */
/* Close the pipe FDs. */
/* TODO ... */
/* We can continue the replication process with all the slaves that
* correctly received the full payload. */
updateSlavesWaitingBgsave((!bysignal && exitcode == 0) ? REDIS_OK : REDIS_ERR, REDIS_RDB_CHILD_TYPE_SOCKET);
}
@ -1317,9 +1333,19 @@ int rdbSaveToSlavesSockets(void) {
listIter li;
pid_t childpid;
long long start;
int pipefds[2];
if (server.rdb_child_pid != -1) return REDIS_ERR;
/* Before to fork, create a pipe that will be used in order to
* send back to the parent the IDs of the slaves that successfully
* received all the writes. */
if (pipe(pipefds) == -1) return REDIS_ERR;
server.rdb_pipe_read_result_from_child = pipefds[0];
server.rdb_pipe_write_result_to_parent = pipefds[1];
/* Collect the file descriptors of the slaves we want to transfer
* the RDB to, which are i WAIT_BGSAVE_START state. */
fds = zmalloc(sizeof(int)*listLength(server.slaves));
numfds = 0;
@ -1333,7 +1359,7 @@ int rdbSaveToSlavesSockets(void) {
}
}
/* Fork ... */
/* Create the child process. */
start = ustime();
if ((childpid = fork()) == 0) {
/* Child */
@ -1365,6 +1391,9 @@ int rdbSaveToSlavesSockets(void) {
if (childpid == -1) {
redisLog(REDIS_WARNING,"Can't save in background: fork: %s",
strerror(errno));
zfree(fds);
close(pipefds[0]);
close(pipefds[1]);
return REDIS_ERR;
}
redisLog(REDIS_NOTICE,"Background RDB transfer started by pid %d",childpid);