`module Streams`

Methods for managing Redis streams.

Definitions

`def xinfo(*arguments)`

Get information on streams and consumer groups. O(N) with N being the number of returned items for the subcommands CONSUMERS and GROUPS. The STREAM subcommand is O(log N) with N being the number of items in the stream. See https://redis.io/commands/xinfo for more details.

Signature

parameter　help　Enum

Implementation

def xinfo(*arguments)
	call("XINFO", *arguments)
end

`def xadd(*arguments)`

Appends a new entry to a stream. O(1). See https://redis.io/commands/xadd for more details.

Signature

parameter　key　Key
parameter　ID　String

Implementation

def xadd(*arguments)
	call("XADD", *arguments)
end

`def xtrim(*arguments)`

Trims the stream to (approximately if '~' is passed) a certain size. O(N), with N being the number of evicted entries. Constant times are very small however, since entries are organized in macro nodes containing multiple entries that can be released with a single deallocation. See https://redis.io/commands/xtrim for more details.

Signature

parameter　key　Key
parameter　strategy　Enum
parameter　approx　Enum
parameter　count　Integer

Implementation

def xtrim(*arguments)
	call("XTRIM", *arguments)
end

`def xdel(*arguments)`

Removes the specified entries from the stream. Returns the number of items actually deleted, that may be different from the number of IDs passed in case certain IDs do not exist. O(1) for each single item to delete in the stream, regardless of the stream size. See https://redis.io/commands/xdel for more details.

Signature

parameter　key　Key
parameter　ID　String

Implementation

def xdel(*arguments)
	call("XDEL", *arguments)
end

`def xrange(*arguments)`

Return a range of elements in a stream, with IDs matching the specified IDs interval. O(N) with N being the number of elements being returned. If N is constant (e.g. always asking for the first 10 elements with COUNT), you can consider it O(1). See https://redis.io/commands/xrange for more details.

Signature

parameter　key　Key
parameter　start　String
parameter　end　String

Implementation

def xrange(*arguments)
	call("XRANGE", *arguments)
end

`def xrevrange(*arguments)`

Return a range of elements in a stream, with IDs matching the specified IDs interval, in reverse order (from greater to smaller IDs) compared to XRANGE. O(N) with N being the number of elements returned. If N is constant (e.g. always asking for the first 10 elements with COUNT), you can consider it O(1). See https://redis.io/commands/xrevrange for more details.

Signature

parameter　key　Key
parameter　end　String
parameter　start　String

Implementation

def xrevrange(*arguments)
	call("XREVRANGE", *arguments)
end

`def xlen(*arguments)`

Return the number of entires in a stream. O(1). See https://redis.io/commands/xlen for more details.

Signature

parameter　key　Key

Implementation

def xlen(*arguments)
	call("XLEN", *arguments)
end

`def xread(*arguments)`

Return never seen elements in multiple streams, with IDs greater than the ones reported by the caller for each stream. Can block. For each stream mentioned: O(N) with N being the number of elements being returned, it means that XREAD-ing with a fixed COUNT is O(1). Note that when the BLOCK option is used, XADD will pay O(M) time in order to serve the M clients blocked on the stream getting new data. See https://redis.io/commands/xread for more details.

Signature

parameter　streams　Enum
parameter　key　Key
parameter　id　String

Implementation

def xread(*arguments)
	call("XREAD", *arguments)
end

`def xgroup(*arguments)`

Create, destroy, and manage consumer groups. O(1) for all the subcommands, with the exception of the DESTROY subcommand which takes an additional O(M) time in order to delete the M entries inside the consumer group pending entries list (PEL). See https://redis.io/commands/xgroup for more details.

Implementation

def xgroup(*arguments)
	call("XGROUP", *arguments)
end

`def xreadgroup(*arguments)`

Return new entries from a stream using a consumer group, or access the history of the pending entries for a given consumer. Can block. For each stream mentioned: O(M) with M being the number of elements returned. If M is constant (e.g. always asking for the first 10 elements with COUNT), you can consider it O(1). On the other side when XREADGROUP blocks, XADD will pay the O(N) time in order to serve the N clients blocked on the stream getting new data. See https://redis.io/commands/xreadgroup for more details.

Signature

parameter　noack　Enum
parameter　streams　Enum
parameter　key　Key
parameter　ID　String

Implementation

def xreadgroup(*arguments)
	call("XREADGROUP", *arguments)
end

`def xack(*arguments)`

Marks a pending message as correctly processed, effectively removing it from the pending entries list of the consumer group. Return value of the command is the number of messages successfully acknowledged, that is, the IDs we were actually able to resolve in the PEL. O(1) for each message ID processed. See https://redis.io/commands/xack for more details.

Signature

parameter　key　Key
parameter　group　String
parameter　ID　String

Implementation

def xack(*arguments)
	call("XACK", *arguments)
end

`def xclaim(*arguments)`

Changes (or acquires) ownership of a message in a consumer group, as if the message was delivered to the specified consumer. O(log N) with N being the number of messages in the PEL of the consumer group. See https://redis.io/commands/xclaim for more details.

Signature

parameter　key　Key
parameter　group　String
parameter　consumer　String
parameter　min-idle-time　String
parameter　ID　String

Implementation

def xclaim(*arguments)
	call("XCLAIM", *arguments)
end

`def xpending(*arguments)`

Return information and entries from a stream consumer group pending entries list, that are messages fetched but never acknowledged. O(N) with N being the number of elements returned, so asking for a small fixed number of entries per call is O(1). When the command returns just the summary it runs in O(1) time assuming the list of consumers is small, otherwise there is additional O(N) time needed to iterate every consumer. See https://redis.io/commands/xpending for more details.

Signature

parameter　key　Key
parameter　group　String
parameter　consumer　String

Implementation

def xpending(*arguments)
	call("XPENDING", *arguments)
end