-
antirez authored
MULTI/EXEC is now propagated to the AOF / Slaves only once we encounter the first command that is not a read-only one inside the transaction. The old behavior was to always propagate an empty MULTI/EXEC block when the transaction was composed just of read only commands, or even completely empty. This created two problems: 1) It's a bandwidth waste in the replication link and a space waste inside the AOF file. 2) We used to always increment server.dirty to force the propagation of the EXEC command, resulting into triggering RDB saves more often than needed. Note: even read-only commands may also trigger writes that will be propagated, when we access a key that is found expired and Redis will synthesize a DEL operation. However there is no need for this to stay inside the transaction itself, but only to be ordered. So for instance something like: MULTI GET foo SET key zap EXEC May be propagated into: DEL foo MULTI SET key zap EXEC While the DEL is outside the transaction, the commands are delivered in the right order and it is not possible for other commands to be inserted between DEL and MULTI.
611dcb56