CODEWITHSUNDEEP
rubyredis
0xSina
0xSina

Reputation: 21553

Redis pipelined order of execution

I am using rub redis gem. Wondering if I do for example:

redis.pipelined do
    REDIS.del("users:#{current_user_id}:i-unread")
    REDIS.lpush("users:#{current_user_id}:i-read", items)
    REDIS.ltrim("users:#{current_user_id}:i-read", 0, Interaction::MAX_INTERACTIONS)
end

is this order of execution guaranteed?

Upvotes: 8

Views: 4389

Answers (2)

railscard
railscard

Reputation: 1848

Yes, it is guaranteed. Generally, redis pipelining is nothing more complicated than queuing server responses in memory, so it does not change the order of queries.

Upvotes: 6

akonsu
akonsu

Reputation: 29536

of course the order is guaranteed, otherwise pipelining would be useless. you can always look at the code. for example, this test clearly assumes that the commands are executed sequentially: https://github.com/redis/redis-rb/blob/master/test/pipelining_commands_test.rb#L32

def test_bulk_and_multi_bulk_commands_mixed
  r.pipelined do
    r.lpush "foo", "s1"
    r.lpush "foo", "s2"
    r.mset("baz", "s3", "qux", "s4")
  end

  assert_equal 2, r.llen("foo")
  assert_equal "s2", r.lpop("foo")
  assert_equal "s1", r.lpop("foo")
  assert_equal "s3", r.get("baz")
  assert_equal "s4", r.get("qux")
end

Upvotes: 6

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