Redis Commands Reference

ParticleDB implements the Redis RESP protocol on port 6379, allowing any Redis client library or redis-cli to interact with ParticleDB as a key-value and data-structure store. All data is persisted through the same ACID storage engine used by SQL queries — writes via Redis are immediately visible through PostgreSQL, gRPC, and every other protocol.

Connecting

# Connect with redis-cli
redis-cli -p 6379

# Connect with authentication
redis-cli -p 6379 -a your_password

# Connect to a specific database
redis-cli -p 6379 -n 0

Any standard Redis client library (ioredis, redis-py, Jedis, etc.) works with ParticleDB’s RESP server.

Strings

String commands operate on simple key-value pairs. Values can be strings, integers, or arbitrary byte sequences.

SET

Set the value of a key, with optional expiration and conditional flags.

Syntax:

SET key value [EX seconds] [PX milliseconds] [NX | XX]

Option	Description
`EX`	Set expiration in seconds
`PX`	Set expiration in milliseconds
`NX`	Only set if the key does not already exist
`XX`	Only set if the key already exists

Return value: OK on success, nil if the condition (NX/XX) was not met.

127.0.0.1:6379> SET user:1:name "Alice"
OK
127.0.0.1:6379> SET session:abc token123 EX 3600
OK
127.0.0.1:6379> SET lock:order NX EX 30
OK

GET

Get the value of a key.

Syntax:

GET key

Return value: The value of the key, or nil if the key does not exist.

127.0.0.1:6379> GET user:1:name
"Alice"
127.0.0.1:6379> GET nonexistent
(nil)

SETNX

Set the value of a key only if it does not already exist. Equivalent to SET key value NX.

Syntax:

SETNX key value

Return value: 1 if the key was set, 0 if it already existed.

127.0.0.1:6379> SETNX mykey "Hello"
(integer) 1
127.0.0.1:6379> SETNX mykey "World"
(integer) 0
127.0.0.1:6379> GET mykey
"Hello"

SETEX

Set the value and expiration (in seconds) of a key. Equivalent to SET key value EX seconds.

Syntax:

SETEX key seconds value

Return value: OK.

127.0.0.1:6379> SETEX cache:page:home 300 "<html>...</html>"
OK
127.0.0.1:6379> TTL cache:page:home
(integer) 300

GETSET

Atomically set a key to a new value and return its old value.

Syntax:

GETSET key value

Return value: The old value of the key, or nil if it did not exist.

127.0.0.1:6379> SET counter "10"
OK
127.0.0.1:6379> GETSET counter "0"
"10"
127.0.0.1:6379> GET counter
"0"

MGET

Get the values of multiple keys in a single round trip.

Syntax:

MGET key [key ...]

Return value: An array of values (or nil for keys that do not exist).

127.0.0.1:6379> SET key1 "a"
OK
127.0.0.1:6379> SET key2 "b"
OK
127.0.0.1:6379> MGET key1 key2 key3
1) "a"
2) "b"
3) (nil)

MSET

Set multiple key-value pairs in a single atomic operation.

Syntax:

MSET key value [key value ...]

Return value: OK (always succeeds).

127.0.0.1:6379> MSET user:1:name "Alice" user:1:email "alice@example.com"
OK
127.0.0.1:6379> MGET user:1:name user:1:email
1) "Alice"
2) "alice@example.com"

INCR

Increment the integer value of a key by one. If the key does not exist, it is set to 0 before the operation.

Syntax:

INCR key

Return value: The value after the increment.

127.0.0.1:6379> SET visits 100
OK
127.0.0.1:6379> INCR visits
(integer) 101
127.0.0.1:6379> INCR visits
(integer) 102

DECR

Decrement the integer value of a key by one.

Syntax:

DECR key

Return value: The value after the decrement.

127.0.0.1:6379> SET stock 50
OK
127.0.0.1:6379> DECR stock
(integer) 49

INCRBY

Increment the integer value of a key by a specified amount.

Syntax:

INCRBY key increment

Return value: The value after the increment.

127.0.0.1:6379> SET counter 10
OK
127.0.0.1:6379> INCRBY counter 5
(integer) 15

DECRBY

Decrement the integer value of a key by a specified amount.

Syntax:

DECRBY key decrement

Return value: The value after the decrement.

127.0.0.1:6379> SET counter 100
OK
127.0.0.1:6379> DECRBY counter 25
(integer) 75

APPEND

Append a value to an existing string. If the key does not exist, it is created with the given value.

Syntax:

APPEND key value

Return value: The length of the string after the append.

127.0.0.1:6379> SET greeting "Hello"
OK
127.0.0.1:6379> APPEND greeting " World"
(integer) 11
127.0.0.1:6379> GET greeting
"Hello World"

STRLEN

Get the length of the string stored at a key.

Syntax:

STRLEN key

Return value: The length of the string, or 0 if the key does not exist.

127.0.0.1:6379> SET name "ParticleDB"
OK
127.0.0.1:6379> STRLEN name
(integer) 10

Lists

Lists are ordered sequences of strings. Elements can be pushed and popped from both ends, making them suitable for queues, stacks, and recent-activity feeds.

LPUSH

Insert one or more values at the head (left) of a list.

Syntax:

LPUSH key value [value ...]

Return value: The length of the list after the push.

127.0.0.1:6379> LPUSH tasks "send email" "write report"
(integer) 2
127.0.0.1:6379> LRANGE tasks 0 -1
1) "write report"
2) "send email"

RPUSH

Insert one or more values at the tail (right) of a list.

Syntax:

RPUSH key value [value ...]

Return value: The length of the list after the push.

127.0.0.1:6379> RPUSH queue "job1" "job2" "job3"
(integer) 3

LPOP

Remove and return the first element of a list.

Syntax:

LPOP key

Return value: The removed element, or nil if the list is empty or does not exist.

127.0.0.1:6379> RPUSH queue "a" "b" "c"
(integer) 3
127.0.0.1:6379> LPOP queue
"a"

RPOP

Remove and return the last element of a list.

Syntax:

RPOP key

Return value: The removed element, or nil if the list is empty or does not exist.

127.0.0.1:6379> RPUSH stack "x" "y" "z"
(integer) 3
127.0.0.1:6379> RPOP stack
"z"

LLEN

Get the number of elements in a list.

Syntax:

LLEN key

Return value: The length of the list, or 0 if the key does not exist.

127.0.0.1:6379> RPUSH items "a" "b" "c"
(integer) 3
127.0.0.1:6379> LLEN items
(integer) 3

LRANGE

Get a range of elements from a list. Indices are zero-based; negative indices count from the end (-1 is the last element).

Syntax:

LRANGE key start stop

Return value: An array of elements in the specified range.

127.0.0.1:6379> RPUSH colors "red" "green" "blue" "yellow"
(integer) 4
127.0.0.1:6379> LRANGE colors 0 -1
1) "red"
2) "green"
3) "blue"
4) "yellow"
127.0.0.1:6379> LRANGE colors 1 2
1) "green"
2) "blue"

LINDEX

Get an element by its index in a list.

Syntax:

LINDEX key index

Return value: The element at the specified index, or nil if out of range.

127.0.0.1:6379> RPUSH letters "a" "b" "c"
(integer) 3
127.0.0.1:6379> LINDEX letters 0
"a"
127.0.0.1:6379> LINDEX letters -1
"c"

LSET

Set the value of an element at a specific index in a list.

Syntax:

LSET key index value

Return value: OK on success. Returns an error if the index is out of range.

127.0.0.1:6379> RPUSH fruits "apple" "banana" "cherry"
(integer) 3
127.0.0.1:6379> LSET fruits 1 "blueberry"
OK
127.0.0.1:6379> LRANGE fruits 0 -1
1) "apple"
2) "blueberry"
3) "cherry"

Sets

Sets are unordered collections of unique strings. They support membership tests, intersections, unions, and differences.

SADD

Add one or more members to a set.

Syntax:

SADD key member [member ...]

Return value: The number of members that were added (excluding already-present members).

127.0.0.1:6379> SADD tags "rust" "database" "olap"
(integer) 3
127.0.0.1:6379> SADD tags "rust"
(integer) 0

SMEMBERS

Get all members of a set.

Syntax:

SMEMBERS key

Return value: An array of all members.

127.0.0.1:6379> SADD colors "red" "blue" "green"
(integer) 3
127.0.0.1:6379> SMEMBERS colors
1) "blue"
2) "green"
3) "red"

SISMEMBER

Test if a value is a member of a set.

Syntax:

SISMEMBER key member

Return value: 1 if the member exists, 0 otherwise.

127.0.0.1:6379> SADD fruits "apple" "banana"
(integer) 2
127.0.0.1:6379> SISMEMBER fruits "apple"
(integer) 1
127.0.0.1:6379> SISMEMBER fruits "cherry"
(integer) 0

SREM

Remove one or more members from a set.

Syntax:

SREM key member [member ...]

Return value: The number of members that were removed.

127.0.0.1:6379> SADD myset "a" "b" "c"
(integer) 3
127.0.0.1:6379> SREM myset "b"
(integer) 1
127.0.0.1:6379> SMEMBERS myset
1) "a"
2) "c"

SCARD

Get the number of members in a set.

Syntax:

SCARD key

Return value: The cardinality (number of elements) of the set.

127.0.0.1:6379> SADD myset "a" "b" "c"
(integer) 3
127.0.0.1:6379> SCARD myset
(integer) 3

SUNION

Return the union of multiple sets.

Syntax:

SUNION key [key ...]

Return value: An array of members in the resulting union.

127.0.0.1:6379> SADD set1 "a" "b" "c"
(integer) 3
127.0.0.1:6379> SADD set2 "b" "c" "d"
(integer) 3
127.0.0.1:6379> SUNION set1 set2
1) "a"
2) "b"
3) "c"
4) "d"

SINTER

Return the intersection of multiple sets.

Syntax:

SINTER key [key ...]

Return value: An array of members present in all given sets.

127.0.0.1:6379> SADD set1 "a" "b" "c"
(integer) 3
127.0.0.1:6379> SADD set2 "b" "c" "d"
(integer) 3
127.0.0.1:6379> SINTER set1 set2
1) "b"
2) "c"

SDIFF

Return the difference between the first set and all subsequent sets.

Syntax:

SDIFF key [key ...]

Return value: An array of members in the first set that are not in any other set.

127.0.0.1:6379> SADD set1 "a" "b" "c"
(integer) 3
127.0.0.1:6379> SADD set2 "b" "c" "d"
(integer) 3
127.0.0.1:6379> SDIFF set1 set2
1) "a"

Sorted Sets

Sorted sets associate a floating-point score with each member. Members are unique and ordered by score, enabling range queries and leaderboard-style access patterns.

ZADD

Add one or more members with scores to a sorted set.

Syntax:

ZADD key score member [score member ...]

Return value: The number of members added (not including updated members).

127.0.0.1:6379> ZADD leaderboard 100 "alice" 85 "bob" 92 "charlie"
(integer) 3

ZSCORE

Get the score of a member in a sorted set.

Syntax:

ZSCORE key member

Return value: The score as a string, or nil if the member does not exist.

127.0.0.1:6379> ZSCORE leaderboard "alice"
"100"

ZRANK

Get the rank (zero-based index) of a member, ordered from lowest to highest score.

Syntax:

ZRANK key member

Return value: The rank as an integer, or nil if the member does not exist.

127.0.0.1:6379> ZADD leaderboard 100 "alice" 85 "bob" 92 "charlie"
(integer) 3
127.0.0.1:6379> ZRANK leaderboard "bob"
(integer) 0
127.0.0.1:6379> ZRANK leaderboard "alice"
(integer) 2

ZRANGE

Get a range of members by index (low to high score). Use WITHSCORES to include scores in the output.

Syntax:

ZRANGE key start stop [WITHSCORES]

Return value: An array of members (and optionally their scores).

127.0.0.1:6379> ZADD leaderboard 100 "alice" 85 "bob" 92 "charlie"
(integer) 3
127.0.0.1:6379> ZRANGE leaderboard 0 -1
1) "bob"
2) "charlie"
3) "alice"
127.0.0.1:6379> ZRANGE leaderboard 0 -1 WITHSCORES
1) "bob"
2) "85"
3) "charlie"
4) "92"
5) "alice"
6) "100"

ZRANGEBYSCORE

Get members with scores within a given range. Use -inf and +inf for unbounded ranges. Prefix a value with ( for an exclusive bound.

Syntax:

ZRANGEBYSCORE key min max [WITHSCORES] [LIMIT offset count]

Return value: An array of members in the score range.

127.0.0.1:6379> ZADD temps 32.5 "NYC" 28.1 "LA" 35.0 "Phoenix" 22.3 "Seattle"
(integer) 4
127.0.0.1:6379> ZRANGEBYSCORE temps 25 33
1) "LA"
2) "NYC"
127.0.0.1:6379> ZRANGEBYSCORE temps -inf +inf WITHSCORES
1) "Seattle"
2) "22.3"
3) "LA"
4) "28.1"
5) "NYC"
6) "32.5"
7) "Phoenix"
8) "35"

ZREM

Remove one or more members from a sorted set.

Syntax:

ZREM key member [member ...]

Return value: The number of members removed.

127.0.0.1:6379> ZADD scores 10 "a" 20 "b" 30 "c"
(integer) 3
127.0.0.1:6379> ZREM scores "b"
(integer) 1

ZCARD

Get the number of members in a sorted set.

Syntax:

ZCARD key

Return value: The cardinality of the sorted set.

127.0.0.1:6379> ZADD scores 10 "a" 20 "b" 30 "c"
(integer) 3
127.0.0.1:6379> ZCARD scores
(integer) 3

Hashes

Hashes map field names to values within a single key. They are ideal for representing objects (e.g., user profiles, configuration entries).

HSET

Set one or more fields in a hash.

Syntax:

HSET key field value [field value ...]

Return value: The number of fields that were added (not updated).

127.0.0.1:6379> HSET user:1 name "Alice" email "alice@example.com" age "30"
(integer) 3

HGET

Get the value of a single field in a hash.

Syntax:

HGET key field

Return value: The value of the field, or nil if the field or key does not exist.

127.0.0.1:6379> HGET user:1 name
"Alice"
127.0.0.1:6379> HGET user:1 nonexistent
(nil)

HGETALL

Get all fields and values in a hash.

Syntax:

HGETALL key

Return value: An array of alternating field names and values.

127.0.0.1:6379> HSET user:1 name "Alice" email "alice@example.com"
(integer) 2
127.0.0.1:6379> HGETALL user:1
1) "name"
2) "Alice"
3) "email"
4) "alice@example.com"

HDEL

Delete one or more fields from a hash.

Syntax:

HDEL key field [field ...]

Return value: The number of fields that were removed.

127.0.0.1:6379> HSET user:1 name "Alice" tmp "delete_me"
(integer) 2
127.0.0.1:6379> HDEL user:1 tmp
(integer) 1

HEXISTS

Check if a field exists in a hash.

Syntax:

HEXISTS key field

Return value: 1 if the field exists, 0 otherwise.

127.0.0.1:6379> HSET user:1 name "Alice"
(integer) 1
127.0.0.1:6379> HEXISTS user:1 name
(integer) 1
127.0.0.1:6379> HEXISTS user:1 phone
(integer) 0

HKEYS

Get all field names in a hash.

Syntax:

HKEYS key

Return value: An array of field names.

127.0.0.1:6379> HSET config host "localhost" port "6379"
(integer) 2
127.0.0.1:6379> HKEYS config
1) "host"
2) "port"

HVALS

Get all values in a hash.

Syntax:

HVALS key

Return value: An array of values.

127.0.0.1:6379> HSET config host "localhost" port "6379"
(integer) 2
127.0.0.1:6379> HVALS config
1) "localhost"
2) "6379"

HLEN

Get the number of fields in a hash.

Syntax:

HLEN key

Return value: The number of fields.

127.0.0.1:6379> HSET user:1 name "Alice" email "alice@example.com" age "30"
(integer) 3
127.0.0.1:6379> HLEN user:1
(integer) 3

HINCRBY

Increment the integer value of a hash field by a given amount.

Syntax:

HINCRBY key field increment

Return value: The value after the increment.

127.0.0.1:6379> HSET user:1 login_count 10
(integer) 1
127.0.0.1:6379> HINCRBY user:1 login_count 1
(integer) 11

HMSET

Set multiple fields in a hash. Functionally identical to HSET with multiple field-value pairs (provided for compatibility).

Syntax:

HMSET key field value [field value ...]

Return value: OK.

127.0.0.1:6379> HMSET user:2 name "Bob" email "bob@example.com"
OK

HMGET

Get the values of multiple fields in a hash.

Syntax:

HMGET key field [field ...]

Return value: An array of values (or nil for fields that do not exist).

127.0.0.1:6379> HSET user:1 name "Alice" email "alice@example.com" age "30"
(integer) 3
127.0.0.1:6379> HMGET user:1 name age phone
1) "Alice"
2) "30"
3) (nil)

HSETNX

Set the value of a hash field only if the field does not already exist.

Syntax:

HSETNX key field value

Return value: 1 if the field was set, 0 if it already existed.

127.0.0.1:6379> HSETNX user:1 name "Alice"
(integer) 1
127.0.0.1:6379> HSETNX user:1 name "Bob"
(integer) 0
127.0.0.1:6379> HGET user:1 name
"Alice"

Streams

Streams are append-only log data structures. Each entry has an auto-generated ID and a set of field-value pairs. Streams support consumer groups, range queries, and blocking reads.

XADD

Append an entry to a stream. Use * to auto-generate the entry ID.

Syntax:

XADD key id field value [field value ...]

Return value: The ID of the added entry.

127.0.0.1:6379> XADD events * action "click" page "/home"
"1679012345678-0"
127.0.0.1:6379> XADD events * action "scroll" page "/about"
"1679012345679-0"

XLEN

Get the number of entries in a stream.

Syntax:

XLEN key

Return value: The number of entries.

127.0.0.1:6379> XLEN events
(integer) 2

XRANGE

Get entries in a stream within an ID range. Use - for the minimum ID and + for the maximum.

Syntax:

XRANGE key start end [COUNT count]

Return value: An array of entries, each containing its ID and field-value pairs.

127.0.0.1:6379> XRANGE events - +
1) 1) "1679012345678-0"
   2) 1) "action"
      2) "click"
      3) "page"
      4) "/home"
2) 1) "1679012345679-0"
   2) 1) "action"
      2) "scroll"
      3) "page"
      4) "/about"
127.0.0.1:6379> XRANGE events - + COUNT 1
1) 1) "1679012345678-0"
   2) 1) "action"
      2) "click"
      3) "page"
      4) "/home"

XREVRANGE

Get entries in reverse order (highest to lowest ID).

Syntax:

XREVRANGE key end start [COUNT count]

Return value: An array of entries in reverse order.

127.0.0.1:6379> XREVRANGE events + - COUNT 1
1) 1) "1679012345679-0"
   2) 1) "action"
      2) "scroll"
      3) "page"
      4) "/about"

XREAD

Read entries from one or more streams, optionally blocking until new data arrives.

Syntax:

XREAD [COUNT count] [BLOCK milliseconds] STREAMS key [key ...] id [id ...]

Use $ as the ID to read only new entries that arrive after the command is issued (blocking mode).

Return value: An array of stream results, each containing the stream key and its entries. Returns nil if the timeout expires with no new data.

# Read up to 10 entries from "events" starting after ID 0
127.0.0.1:6379> XREAD COUNT 10 STREAMS events 0
1) 1) "events"
   2) 1) 1) "1679012345678-0"
         2) 1) "action"
            2) "click"
            3) "page"
            4) "/home"

# Block for up to 5 seconds waiting for new entries
127.0.0.1:6379> XREAD COUNT 1 BLOCK 5000 STREAMS events $

XTRIM

Trim a stream to a maximum length, removing the oldest entries.

Syntax:

XTRIM key MAXLEN [~] count

Use ~ for approximate trimming (more efficient, may keep slightly more entries).

Return value: The number of entries removed.

127.0.0.1:6379> XTRIM events MAXLEN 1000
(integer) 0
127.0.0.1:6379> XTRIM events MAXLEN ~ 1000
(integer) 0

XINFO STREAM

Get information about a stream.

Syntax:

XINFO STREAM key

Return value: A detailed map of stream metadata including length, first/last entry, and radix tree statistics.

127.0.0.1:6379> XINFO STREAM events
 1) "length"
 2) (integer) 2
 3) "radix-tree-keys"
 4) (integer) 1
 5) "radix-tree-nodes"
 6) (integer) 2
 7) "last-generated-id"
 8) "1679012345679-0"
 9) "first-entry"
10) 1) "1679012345678-0"
    2) 1) "action"
       2) "click"
       3) "page"
       4) "/home"
11) "last-entry"
12) 1) "1679012345679-0"
    2) 1) "action"
       2) "scroll"
       3) "page"
       4) "/about"

Keys

Key commands operate on keys regardless of the underlying data type.

DEL

Delete one or more keys.

Syntax:

DEL key [key ...]

Return value: The number of keys that were deleted.

127.0.0.1:6379> SET a 1
OK
127.0.0.1:6379> SET b 2
OK
127.0.0.1:6379> DEL a b nonexistent
(integer) 2

EXISTS

Check if one or more keys exist.

Syntax:

EXISTS key [key ...]

Return value: The number of specified keys that exist.

127.0.0.1:6379> SET mykey "hello"
OK
127.0.0.1:6379> EXISTS mykey
(integer) 1
127.0.0.1:6379> EXISTS mykey otherkey
(integer) 1

TYPE

Get the data type of a key.

Syntax:

TYPE key

Return value: One of string, list, set, zset, hash, stream, or none.

127.0.0.1:6379> SET name "Alice"
OK
127.0.0.1:6379> TYPE name
string
127.0.0.1:6379> LPUSH mylist "a"
(integer) 1
127.0.0.1:6379> TYPE mylist
list

KEYS

Find all keys matching a glob-style pattern. Use * to match all keys.

Syntax:

KEYS pattern

Return value: An array of matching keys.

127.0.0.1:6379> SET user:1 "Alice"
OK
127.0.0.1:6379> SET user:2 "Bob"
OK
127.0.0.1:6379> SET order:1 "pending"
OK
127.0.0.1:6379> KEYS user:*
1) "user:1"
2) "user:2"
127.0.0.1:6379> KEYS *
1) "user:1"
2) "user:2"
3) "order:1"

SCAN

Incrementally iterate over keys using a cursor. Returns a new cursor and a batch of keys; pass the returned cursor to the next call until the cursor is 0.

Syntax:

SCAN cursor [MATCH pattern] [COUNT hint]

Return value: A two-element array: the next cursor and an array of keys.

127.0.0.1:6379> SCAN 0 MATCH user:* COUNT 100
1) "0"
2) 1) "user:1"
   2) "user:2"

TTL

Get the remaining time to live (in seconds) for a key with an expiration.

Syntax:

TTL key

Return value: TTL in seconds, -1 if the key has no expiration, -2 if the key does not exist.

127.0.0.1:6379> SET session "abc" EX 300
OK
127.0.0.1:6379> TTL session
(integer) 300
127.0.0.1:6379> TTL permanent_key
(integer) -1

PTTL

Get the remaining time to live in milliseconds.

Syntax:

PTTL key

Return value: TTL in milliseconds, -1 if no expiration, -2 if key does not exist.

127.0.0.1:6379> SET session "abc" PX 60000
OK
127.0.0.1:6379> PTTL session
(integer) 59985

EXPIRE

Set an expiration (in seconds) on an existing key.

Syntax:

EXPIRE key seconds

Return value: 1 if the timeout was set, 0 if the key does not exist.

127.0.0.1:6379> SET mykey "hello"
OK
127.0.0.1:6379> EXPIRE mykey 60
(integer) 1
127.0.0.1:6379> TTL mykey
(integer) 60

PERSIST

Remove the expiration from a key, making it persist indefinitely.

Syntax:

PERSIST key

Return value: 1 if the timeout was removed, 0 if the key does not exist or had no timeout.

127.0.0.1:6379> SET temp "data" EX 100
OK
127.0.0.1:6379> PERSIST temp
(integer) 1
127.0.0.1:6379> TTL temp
(integer) -1

RENAME

Rename a key. If the destination key already exists, it is overwritten.

Syntax:

RENAME key newkey

Return value: OK on success. Returns an error if the source key does not exist.

127.0.0.1:6379> SET old_name "value"
OK
127.0.0.1:6379> RENAME old_name new_name
OK
127.0.0.1:6379> GET new_name
"value"

RANDOMKEY

Return a random key from the current database.

Syntax:

RANDOMKEY

Return value: A random key, or nil if the database is empty.

127.0.0.1:6379> RANDOMKEY
"user:1"

Pub/Sub

Publish/Subscribe messaging allows clients to subscribe to channels and receive messages published by other clients in real time.

Subscribe to one or more channels. The client enters a subscription mode and receives messages as they are published.

Syntax:

SUBSCRIBE channel [channel ...]

Return value: Subscription confirmation messages, then incoming messages as they arrive.

127.0.0.1:6379> SUBSCRIBE notifications alerts
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "notifications"
3) (integer) 1
1) "subscribe"
2) "alerts"
3) (integer) 2

PUBLISH

Publish a message to a channel. All clients subscribed to that channel will receive it.

Syntax:

PUBLISH channel message

Return value: The number of clients that received the message.

127.0.0.1:6379> PUBLISH notifications "New order received"
(integer) 2

UNSUBSCRIBE

Unsubscribe from one or more channels. If no channels are specified, unsubscribe from all channels.

Syntax:

UNSUBSCRIBE [channel [channel ...]]

Return value: Unsubscription confirmation messages.

127.0.0.1:6379> UNSUBSCRIBE notifications
1) "unsubscribe"
2) "notifications"
3) (integer) 0

Transactions

Redis transactions allow grouping multiple commands into an atomic unit. All commands between MULTI and EXEC are queued and executed together.

MULTI

Start a transaction. Subsequent commands are queued until EXEC or DISCARD.

Syntax:

MULTI

Return value: OK.

127.0.0.1:6379> MULTI
OK
127.0.0.1:6379(TX)> SET balance:alice 100
QUEUED
127.0.0.1:6379(TX)> SET balance:bob 200
QUEUED
127.0.0.1:6379(TX)> EXEC
1) OK
2) OK

EXEC

Execute all queued commands in the transaction.

Syntax:

EXEC

Return value: An array of results, one per queued command.

127.0.0.1:6379> MULTI
OK
127.0.0.1:6379(TX)> INCR counter
QUEUED
127.0.0.1:6379(TX)> INCR counter
QUEUED
127.0.0.1:6379(TX)> EXEC
1) (integer) 1
2) (integer) 2

DISCARD

Discard all queued commands and exit the transaction.

Syntax:

DISCARD

Return value: OK.

127.0.0.1:6379> MULTI
OK
127.0.0.1:6379(TX)> SET key "value"
QUEUED
127.0.0.1:6379(TX)> DISCARD
OK

Server

Server commands provide administrative and diagnostic capabilities.

PING

Test connectivity. Returns PONG or echoes the provided message.

Syntax:

PING [message]

Return value: PONG, or the provided message.

127.0.0.1:6379> PING
PONG
127.0.0.1:6379> PING "hello"
"hello"

ECHO

Echo the given message back to the client.

Syntax:

ECHO message

Return value: The message.

127.0.0.1:6379> ECHO "ParticleDB"
"ParticleDB"

QUIT

Close the connection.

Syntax:

QUIT

Return value: OK.

127.0.0.1:6379> QUIT
OK

SELECT

Select the database by index. ParticleDB supports multiple logical databases (numbered 0-15 by default).

Syntax:

SELECT index

Return value: OK.

127.0.0.1:6379> SELECT 1
OK
127.0.0.1:6379[1]> SET key "in db 1"
OK

DBSIZE

Return the number of keys in the currently selected database.

Syntax:

DBSIZE

Return value: The number of keys.

127.0.0.1:6379> DBSIZE
(integer) 42

FLUSHDB

Delete all keys in the currently selected database.

Syntax:

FLUSHDB

Return value: OK.

127.0.0.1:6379> FLUSHDB
OK
127.0.0.1:6379> DBSIZE
(integer) 0

FLUSHALL

Delete all keys in all databases.

Syntax:

FLUSHALL

Return value: OK.

127.0.0.1:6379> FLUSHALL
OK

INFO

Return server information and statistics. Optionally specify a section.

Syntax:

INFO [section]

Return value: A bulk string of server information.

127.0.0.1:6379> INFO server
# Server
particledb_version:0.1.0
tcp_port:6379
uptime_in_seconds:3600
...

127.0.0.1:6379> INFO memory
# Memory
used_memory:1048576
used_memory_human:1.00M
...

CONFIG GET

Get the value of a configuration parameter.

Syntax:

CONFIG GET parameter

Return value: An array of parameter name and value pairs. Supports glob patterns.

127.0.0.1:6379> CONFIG GET maxmemory
1) "maxmemory"
2) "0"
127.0.0.1:6379> CONFIG GET save
1) "save"
2) ""

TIME

Return the current server time as a two-element array: Unix timestamp in seconds and microseconds.

Syntax:

TIME

Return value: A two-element array of strings.

127.0.0.1:6379> TIME
1) "1679012345"
2) "678901"

AUTH

Authenticate with the server. Required if the server is configured with a password.

Syntax:

AUTH password
AUTH username password

Return value: OK on success. Returns an error if the credentials are invalid.

127.0.0.1:6379> AUTH my_secret_password
OK
127.0.0.1:6379> AUTH admin my_secret_password
OK

Notes

All data structures share the same ACID storage engine as SQL tables. Writes through Redis commands are durable according to the configured WAL sync mode.
Data written via the Redis protocol is accessible through SQL, gRPC, HTTP, and WebSocket protocols, and vice versa.
For production workloads, use SCAN instead of KEYS to avoid blocking the server on large keyspaces.
Connection pooling from Redis client libraries (e.g., ioredis maxRetriesPerRequest, redis-py ConnectionPool) works as expected.