# BITOP ```json metadata { "title": "BITOP", "description": "Performs bitwise operations on multiple strings, and stores the result.", "categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"], "arguments": [{"arguments":[{"display_text":"and","name":"and","token":"AND","type":"pure-token"},{"display_text":"or","name":"or","token":"OR","type":"pure-token"},{"display_text":"xor","name":"xor","token":"XOR","type":"pure-token"},{"display_text":"not","name":"not","token":"NOT","type":"pure-token"}],"name":"operation","type":"oneof"},{"display_text":"destkey","key_spec_index":0,"name":"destkey","type":"key"},{"display_text":"key","key_spec_index":1,"multiple":true,"name":"key","type":"key"}], "syntax_fmt": "BITOP \u003cAND | OR | XOR | NOT | DIFF | DIFF1 | ANDOR | ONE\u003e destkey key [key ...]", "complexity": "O(N)", "group": "bitmap", "command_flags": ["write","denyoom"], "acl_categories": ["@write","@bitmap","@slow"], "since": "2.6.0", "arity": -4, "key_specs": [{"OW":true,"begin_search":{"spec":{"index":2},"type":"index"},"find_keys":{"spec":{"keystep":1,"lastkey":0,"limit":0},"type":"range"},"update":true},{"RO":true,"access":true,"begin_search":{"spec":{"index":3},"type":"index"},"find_keys":{"spec":{"keystep":1,"lastkey":-1,"limit":0},"type":"range"}}], "tableOfContents": {"sections":[{"id":"handling-of-strings-with-different-lengths","title":"Handling of strings with different lengths"},{"id":"examples","title":"Examples"},{"id":"pattern-real-time-metrics-using-bitmaps","title":"Pattern: real time metrics using bitmaps"},{"id":"performance-considerations","title":"Performance considerations"},{"id":"redis-enterprise-and-redis-cloud-compatibility","title":"Redis Enterprise and Redis Cloud compatibility"},{"id":"return-information","title":"Return information"}]} } ``` Perform a bitwise operation between multiple keys (containing string values) and store the result in the destination key. The `BITOP` command supports eight bitwise operations: `AND`, `OR`, `XOR`, `NOT`, `DIFF`, `DIFF1`, `ANDOR`, and `ONE`. The valid forms to call the command are: * `BITOP AND destkey srckey1 srckey2 srckey3 ... srckeyN` A bit in `destkey` is set only if it is set in all source bitmaps. * `BITOP OR destkey srckey1 srckey2 srckey3 ... srckeyN` A bit in `destkey` is set only if it is set in at least one source bitmap. * `BITOP XOR destkey srckey1 srckey2 srckey3 ... srckeyN` Mostly used with two source bitmaps, a bit in `destkey` is set only if its value differs between the two source bitmaps. * `BITOP NOT destkey srckey` `NOT` is a unary operator and only supports a single source bitmap; set the bit to the inverse of its value in the source bitmap. * `BITOP DIFF destkey X [Y1 Y2 ...]` [1](#list-note-1) A bit in `destkey` is set if it is set in `X`, but not in any of `Y1, Y2, ...` . * `BITOP DIFF1 destkey X [Y1 Y2 ...]` [1](#list-note-1) A bit in `destkey` is set if it is set in one or more of `Y1, Y2, ...`, but not in `X`. * `BITOP ANDOR destkey X [Y1 Y2 ...]` [1](#list-note-1) A bit in `destkey` is set if it is set in `X` and also in one or more of `Y1, Y2, ...`. * `BITOP ONE destkey X1 [X2 X3 ...]` [1](#list-note-1) A bit in `destkey` is set if it is set in exactly one of `X1, X2, ...`. The result of each operation is always stored at `destkey`. 1. Added in Redis 8.2. ## Handling of strings with different lengths When an operation is performed between strings having different lengths, all the strings shorter than the longest string in the set are treated as if they were zero-padded up to the length of the longest string. The same holds true for non-existent keys, that are considered as a stream of zero bytes up to the length of the longest string. ## Examples 1. Basic usage example using the `AND` operator: BITFIELD key1 SET i8 #0 255 BITFIELD key2 SET i8 #0 85 BITOP AND dest key1 key2 BITFIELD dest GET i8 #0 2. Suppose you want to expose people to a book-related ad. The target audience is people who love to read books and are interested in fantasy, adventure, or science fiction. Assume you have the following bitmaps: * `LRB` - people who love to read books. * `B:F` - people interested in fantasy. * `B:A` - people interested in adventure. * `B:SF` - people interested in science fiction. To create a bitmap representing the target audience, use the following command: ``` BITOP ANDOR TA LRB B:F B:A B:SF ``` ## Pattern: real time metrics using bitmaps `BITOP` is a good complement to the pattern documented in the [`BITCOUNT`](https://redis.io/docs/latest/commands/bitcount) command documentation. Different bitmaps can be combined in order to obtain a target bitmap where the population counting operation is performed. See the article called "[Fast easy realtime metrics using Redis bitmaps][hbgc212fermurb]" for an interesting use cases. [hbgc212fermurb]: http://blog.getspool.com/2011/11/29/fast-easy-realtime-metrics-using-redis-bitmaps ## Performance considerations `BITOP` is a potentially slow command as it runs in O(N) time. Care should be taken when running it against long input strings. For real-time metrics and statistics involving large inputs a good approach is to use a replica (with replica-read-only option enabled) where the bit-wise operations are performed to avoid blocking the master instance. ## Redis Enterprise and Redis Cloud compatibility | Redis
Enterprise | Redis
Cloud | Notes | |:----------------------|:-----------------|:------| | ✅ Standard
✅ Active-Active | ✅ Standard
✅ Active-Active | | ## Return information {{< multitabs id="bitop-return-info" tab1="RESP2" tab2="RESP3" >}} [Integer reply](../../develop/reference/protocol-spec#integers): the size of the string stored in the destination key is equal to the size of the longest input string. -tab-sep- [Integer reply](../../develop/reference/protocol-spec#integers): the size of the string stored in the destination key is equal to the size of the longest input string.