List commands

Goblin Core's adaptive-PMA and segmented-listpack backends implement Redis-compatible ordered string lists. Commands are atomic in the normal single-owner execution path. The storage design is documented in Goblin Core Lists. The measured 100,000-element comparison is in List Benchmark. A local same-server comparison of the queue commands is in List Work-Queue Benchmark.

Every operation has implementation-qualified names. Standard Redis names resolve through --list-implementation pma|segmented; segmented lists are the default. Prefix any command in the table with GOBLIN.PMA. or GOBLIN.SEGMENTED. to address one implementation directly.

Command	Syntax	Reply
`LPUSH`	`LPUSH key value [value ...]`	list length
`RPUSH`	`RPUSH key value [value ...]`	list length
`LPUSHX`	`LPUSHX key value [value ...]`	list length, or `0` if absent
`RPUSHX`	`RPUSHX key value [value ...]`	list length, or `0` if absent
`LPOP`	`LPOP key [count]`	value, values, or nil
`RPOP`	`RPOP key [count]`	value, values, or nil
`LMOVE`	`LMOVE source destination LEFT/RIGHT LEFT/RIGHT`	moved value or nil
`RPOPLPUSH`	`RPOPLPUSH source destination`	moved value or nil
`BLPOP`	`BLPOP key [key ...] timeout`	selected key and value, or nil
`BRPOP`	`BRPOP key [key ...] timeout`	selected key and value, or nil
`BLMOVE`	`BLMOVE source destination LEFT/RIGHT LEFT/RIGHT timeout`	moved value or nil
`LMPOP`	`LMPOP numkeys key [key ...] LEFT/RIGHT [COUNT count]`	selected key and values, or nil
`BLMPOP`	`BLMPOP timeout numkeys key [key ...] LEFT/RIGHT [COUNT count]`	selected key and values, or nil
`LLEN`	`LLEN key`	element count
`LINDEX`	`LINDEX key index`	value or nil
`LRANGE`	`LRANGE key start stop`	values in the inclusive range
`LSET`	`LSET key index value`	`OK`, or an index/key error
`LTRIM`	`LTRIM key start stop`	`OK`
`LREM`	`LREM key count value`	number removed
`LINSERT`	`LINSERT key BEFORE/AFTER pivot value`	new length, `0`, or `-1`

The segmented backend exposes the identical suffixes under GOBLIN.SEGMENTED.*: for example, GOBLIN.SEGMENTED.RPUSH, GOBLIN.SEGMENTED.LINDEX, and GOBLIN.SEGMENTED.LINSERT. A qualified push selects the representation when it creates a key. Later standard or qualified list commands operate on that existing representation without conversion.

Negative indexes count back from the tail. LRANGE and LTRIM use inclusive end indexes. LREM scans from the head for positive counts, from the tail for negative counts, and removes all matches when count is zero.

LMOVE atomically removes one endpoint and inserts it at either endpoint of the destination; using one key rotates that list. RPOPLPUSH is the compatible RIGHT-to-LEFT form. LMPOP selects the first non-empty key in argument order and removes one value by default or up to the positive COUNT.

BLPOP, BRPOP, BLMOVE, and BLMPOP first attempt the corresponding operation immediately. If no source is ready, only that client is parked; the single-owner server continues processing other clients and every command stays atomic. Waiters are served FIFO, while keys within one request are checked in argument order. The timeout is a non-negative number of seconds and may be fractional; zero waits indefinitely. A blocking command executed by a script or inside EXEC uses its non-blocking form and returns nil when no item is ready. The server does not consume later pipelined commands from that connection until the blocked reply has been produced. See the Redis list command surface for the compatible queue patterns.

Keys are limited to 65,535 bytes. List values use the shared string encoding: raw values contain up to 65,534 logical bytes, while --use-lz4 can admit a larger compressible value when its complete encoding fits 65,535 bytes. A command with multiple new values validates the entire input before mutating the list. --disable-encoding stores list values verbatim, disables LZ4, and permits the full 65,535-byte direct value for clients that already use compact binary data.