Couchbase is a high performance NoSQL document store that has evolved from the combination of Memcached and CouchDB. The Couchbase binary protocol is based off of the Memcached binary protocol.
This document has been adapted from the Memcached 'Binary Protocol Revamped' document and may make reference to parts of the protocol not implemented by Couchbase Server.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.
General format of a packet:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| HEADER |
| |
| |
| |
+---------------+---------------+---------------+---------------+
24| COMMAND-SPECIFIC EXTRAS (as needed) |
| (note length in the extras length header field) |
+---------------+---------------+---------------+---------------+
m| Key (as needed) |
| (note length in key length header field) |
+---------------+---------------+---------------+---------------+
n| Value (as needed) |
| (note length is total body length header field, minus |
| sum of the extras and key length body fields) |
+---------------+---------------+---------------+---------------+
Total 24 + x bytes (24 byte header, and x byte body)
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Magic | Opcode | Key length |
+---------------+---------------+---------------+---------------+
4| Extras length | Data type | vbucket id |
+---------------+---------------+---------------+---------------+
8| Total body length |
+---------------+---------------+---------------+---------------+
12| Opaque |
+---------------+---------------+---------------+---------------+
16| CAS |
| |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Magic | Opcode | Key Length |
+---------------+---------------+---------------+---------------+
4| Extras length | Data type | Status |
+---------------+---------------+---------------+---------------+
8| Total body length |
+---------------+---------------+---------------+---------------+
12| Opaque |
+---------------+---------------+---------------+---------------+
16| CAS |
| |
+---------------+---------------+---------------+---------------+
Total 24 bytes
When enabled by the client (via HELLO) the server is allowed to inject flexible framing extensions in the response packet.
When the server decides to inject extra data in the packet, it does so by using a different value for magic (0x18 instead of 0x81), which tells the receiver that the current header looks like:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Magic (0x18) | Opcode | Framing extras| Key Length |
+---------------+---------------+---------------+---------------+
4| Extras length | Data type | Status |
+---------------+---------------+---------------+---------------+
8| Total body length |
+---------------+---------------+---------------+---------------+
12| Opaque |
+---------------+---------------+---------------+---------------+
16| CAS |
| |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Following the header you'd now find the section containing the framing extras (the size is specified in byte 2). Following the framing extras you'll find the extras, then the key and finally the value. The size of the value is total body length - key length - extras length - framing extras.
The framing extras is encoded as a series of variable-length FrameInfo objects.
Each FrameInfo consists of:
- 4 bits: Object Identifier. Encodes first 15 object IDs directly; with the 16th value (15) used
as an escape to support an additional 256 IDs by combining the value of the next byte:
0..14: Identifier for this element.15: Escape: ID is 15 + value of next byte.
- 4 bits: Object Length. Encodes sizes 0..14 directly; value 15 is
used to encode sizes above 14 by combining the value of a following
byte:
0..14: Size in bytes of the element data.15: Escape: Size is 15 + value of next byte (after any object ID escape bytes).
- N Bytes: Object data.
For V1, only one object identifier is defined:
Time (in microseconds) server spent on the operation. Measured from receiving header from OS to when response given to OS. Size: 2 bytes; encoded as variable-precision value (see below)
FrameInfo encoded as:
Byte/ 0 | 1 | 2 |
/ | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+
0| ID:0 | Len:2 | Server Recv->Send Duration |
The duration in micros is encoded as:
encoded = (micros * 2) ^ (1.0 / 1.74)
decoded = (encoded ^ 1.74) / 2
- Magic: Magic number identifying the package (See Magic_Byte)
- Opcode: Command code (See Command Opcodes
- Key length: Length in bytes of the text key that follows the command extras
- vbucket id (Request only): The virtual bucket for this command
- Status (Response Only): Status of the response (non-zero on error) (See Response Status)
- Extras length: Length in bytes of the command extras
- Data type: Reserved for future use (See Data Types)
- Total body length: Length in bytes of extra + key + value
- Opaque: Will be copied back to you in the response
- CAS: Data version check
| Raw | Description |
|---|---|
| 0x80 | Request packet from client to server |
| 0x81 | Response packet from server to client |
| 0x18 | Response packet containing flex extras |
| 0x82 | Request packet from server to client |
| 0x83 | Response packet from client to server |
Magic byte / version. For each version of the protocol, we'll use a different request/response value pair. This is useful for protocol analyzers to distinguish the nature of the packet from the direction which it is moving. Note, it is common to run a memcached instance on a host that also runs an application server. Such a host will both send and receive memcache packets.
The version should hopefully correspond only to different meanings of the command byte. In an ideal world, we will not change the header format. As reserved bytes are given defined meaning, the protocol version / magic byte values should be incremented.
Traffic analysis tools are encouraged to identify memcache packets and provide detailed interpretation if the magic bytes are recognized and otherwise to provide a generic breakdown of the packet. Note, that the key and value positions can always be identified even if the magic byte or command opcode are not recognized.
Possible values of this two-byte field:
| Raw | Description |
|---|---|
| 0x0000 | No error |
| 0x0001 | Key not found |
| 0x0002 | Key exists |
| 0x0003 | Value too large |
| 0x0004 | Invalid arguments |
| 0x0005 | Item not stored |
| 0x0006 | Incr/Decr on a non-numeric value |
| 0x0007 | The vbucket belongs to another server |
| 0x0008 | The connection is not connected to a bucket |
| 0x001f | The authentication context is stale, please re-authenticate |
| 0x0020 | Authentication error |
| 0x0021 | Authentication continue |
| 0x0022 | The requested value is outside the legal ranges |
| 0x0023 | Rollback required |
| 0x0024 | No access |
| 0x0025 | The node is being initialized |
| 0x0081 | Unknown command |
| 0x0082 | Out of memory |
| 0x0083 | Not supported |
| 0x0084 | Internal error |
| 0x0085 | Busy |
| 0x0086 | Temporary failure |
| 0x00c0 | (Subdoc) The provided path does not exist in the document |
| 0x00c1 | (Subdoc) One of path components treats a non-dictionary as a dictionary, or a non-array as an array |
| 0x00c2 | (Subdoc) The path’s syntax was incorrect |
| 0x00c3 | (Subdoc) The path provided is too large; either the string is too long, or it contains too many components |
| 0x00c4 | (Subdoc) The document has too many levels to parse |
| 0x00c5 | (Subdoc) The value provided will invalidate the JSON if inserted |
| 0x00c6 | (Subdoc) The existing document is not valid JSON |
| 0x00c7 | (Subdoc) The existing number is out of the valid range for arithmetic ops |
| 0x00c8 | (Subdoc) The operation would result in a number outside the valid range |
| 0x00c9 | (Subdoc) The requested operation requires the path to not already exist, but it exists |
| 0x00ca | (Subdoc) Inserting the value would cause the document to be too deep |
| 0x00cb | (Subdoc) An invalid combination of commands was specified |
| 0x00cc | (Subdoc) Specified key was successfully found, but one or more path operations failed. Examine the individual lookup_result (MULTI_LOOKUP) / mutation_result (MULTI_MUTATION) structures for details. |
| 0x00cd | (Subdoc) Operation completed successfully on a deleted document |
| 0x00ce | (Subdoc) The flag combination doesn't make any sense |
| 0x00cf | (Subdoc) The key combination of the xattrs is not allowed |
| 0x00d0 | (Subdoc) The server don't know about the specified macro |
| 0x00d1 | (Subdoc) The server don't know about the specified virtual attribute |
| 0x00d2 | (Subdoc) Can't modify virtual attributes |
| 0x00d3 | (Subdoc) One or more paths in a multi-path command failed on a deleted document |
| 0x00d4 | (Subdoc) Invalid XATTR order (xattrs should come first) |
In addition to the above defined status codes, the range 0xff00 - 0xffff is reserved for end-user applications (e.g. proxies). Couchbase itself will not return them.
A well written client should provide logic to gracefully recover from unknown error codes being returned. The status code falls into two main categories: Success or Failure.
If the operation was successfully performed the status field is set to
No error. All other return values means that the operation was not
performed, and these error codes falls into two categories: temporarily and
permanent.
-
A temporary failure is a problem that might go away by resending the operation. There is currently two status codes that may be returned for that:
Busy- The server is too busy to handle your request, please back offTemporary failure- The server hit a problem that a retry might fix
-
A permanent failure is a problem is a failure where the server expects the same result if the command is resent (unless an external actor act on the system (ex: define a user/bucket, change ownership of vbuckets etc). Some permanent failures may be resolved by simply running other commands (ex:
No bucketmay be resolved by selecting a bucket,Authentication stalemay be resolved by re-authenticating to the server). Other permanent failures may require the connection to be re-established.
Possible values of the one-byte field. See Commands for more information about a given command.
| Raw | Description |
|---|---|
| 0x00 | Get |
| 0x01 | Set |
| 0x02 | Add |
| 0x03 | Replace |
| 0x04 | Delete |
| 0x05 | Increment |
| 0x06 | Decrement |
| 0x07 | Quit |
| 0x08 | Flush |
| 0x09 | GetQ |
| 0x0a | No-op |
| 0x0b | Version |
| 0x0c | GetK |
| 0x0d | GetKQ |
| 0x0e | Append |
| 0x0f | Prepend |
| 0x10 | Stat |
| 0x11 | SetQ |
| 0x12 | AddQ |
| 0x13 | ReplaceQ |
| 0x14 | DeleteQ |
| 0x15 | IncrementQ |
| 0x16 | DecrementQ |
| 0x17 | QuitQ |
| 0x18 | FlushQ |
| 0x19 | AppendQ |
| 0x1a | PrependQ |
| 0x1b | Verbosity |
| 0x1c | Touch |
| 0x1d | GAT |
| 0x1e | GATQ |
| 0x1f | HELO |
| 0x20 | SASL list mechs |
| 0x21 | SASL Auth |
| 0x22 | SASL Step |
| 0x23 | Ioctl get |
| 0x24 | Ioctl set |
| 0x25 | Config validate |
| 0x26 | Config reload |
| 0x27 | Audit put |
| 0x28 | Audit config reload |
| 0x29 | Shutdown |
| 0x30 | RGet |
| 0x31 | RSet |
| 0x32 | RSetQ |
| 0x33 | RAppend |
| 0x34 | RAppendQ |
| 0x35 | RPrepend |
| 0x36 | RPrependQ |
| 0x37 | RDelete |
| 0x38 | RDeleteQ |
| 0x39 | RIncr |
| 0x3a | RIncrQ |
| 0x3b | RDecr |
| 0x3c | RDecrQ |
| 0x3d | Set VBucket |
| 0x3e | Get VBucket |
| 0x3f | Del VBucket |
| 0x40 | TAP Connect |
| 0x41 | TAP Mutation |
| 0x42 | TAP Delete |
| 0x43 | TAP Flush |
| 0x44 | TAP Opaque |
| 0x45 | TAP VBucket Set |
| 0x46 | TAP Checkout Start |
| 0x47 | TAP Checkpoint End |
| 0x48 | Get all vb seqnos |
| 0x50 | Dcp Open |
| 0x51 | Dcp add stream |
| 0x52 | Dcp close stream |
| 0x53 | Dcp stream req |
| 0x54 | Dcp get failover log |
| 0x55 | Dcp stream end |
| 0x56 | Dcp snapshot marker |
| 0x57 | Dcp mutation |
| 0x58 | Dcp deletion |
| 0x59 | Dcp expiration |
| 0x5a | Dcp flush |
| 0x5b | Dcp set vbucket state |
| 0x5c | Dcp noop |
| 0x5d | Dcp buffer acknowledgement |
| 0x5e | Dcp control |
| 0x5f | Dcp reserved4 |
| 0x80 | Stop persistence |
| 0x81 | Start persistence |
| 0x82 | Set param |
| 0x83 | Get replica |
| 0x85 | Create bucket |
| 0x86 | Delete bucket |
| 0x87 | List buckets |
| 0x89 | Select bucket |
| 0x8a | Assume role |
| 0x91 | Observe seqno |
| 0x92 | Observe |
| 0x93 | Evict key |
| 0x94 | Get locked |
| 0x95 | Unlock key |
| 0x97 | Last closed checkpoint |
| 0x9e | Deregister tap client |
| 0x9f | Reset replication chain |
| 0xa0 | Get meta |
| 0xa1 | Getq meta |
| 0xa2 | Set with meta |
| 0xa3 | Setq with meta |
| 0xa4 | Add with meta |
| 0xa5 | Addq with meta |
| 0xa6 | Snapshot vb states |
| 0xa7 | Vbucket batch count |
| 0xa8 | Del with meta |
| 0xa9 | Delq with meta |
| 0xaa | Create checkpoint |
| 0xac | Notify vbucket update |
| 0xad | Enable traffic |
| 0xae | Disable traffic |
| 0xb0 | Change vb filter |
| 0xb1 | Checkpoint persistence |
| 0xb2 | Return meta |
| 0xb3 | Compact db |
| 0xb4 | Set cluster config |
| 0xb5 | Get cluster config |
| 0xb6 | Get random key |
| 0xb7 | Seqno persistence |
| 0xb8 | Get keys |
| 0xc1 | Set drift counter state |
| 0xc2 | Get adjusted time |
| 0xc5 | Subdoc get |
| 0xc6 | Subdoc exists |
| 0xc7 | Subdoc dict add |
| 0xc8 | Subdoc dict upsert |
| 0xc9 | Subdoc delete |
| 0xca | Subdoc replace |
| 0xcb | Subdoc array push last |
| 0xcc | Subdoc array push first |
| 0xcd | Subdoc array insert |
| 0xce | Subdoc array add unique |
| 0xcf | Subdoc counter |
| 0xd0 | Subdoc multi lookup |
| 0xd1 | Subdoc multi mutation |
| 0xd2 | Subdoc get count |
| 0xf0 | Scrub |
| 0xf1 | Isasl refresh |
| 0xf2 | Ssl certs refresh |
| 0xf3 | Get cmd timer |
| 0xf4 | Set ctrl token |
| 0xf5 | Get ctrl token |
| 0xf6 | Init complete |
As a convention all of the commands ending with "Q" for Quiet. A quiet version of a command will omit responses that are considered uninteresting. Whether a given response is interesting is dependent upon the command. See the descriptions of the set commands (Section 4.2) and set commands (Section 4.3) for examples of commands that include quiet variants.
| Raw | Description |
|---|---|
| 0x00 |
Possible values of the one-byte field which is a bit-filed.
| Bit | Description |
|---|---|
| 0x01 | JSON |
| 0x02 | Snappy compressed |
| 0x04 | Extended attributes (XATTR) |
If no bits is set the datatype is considered to be RAW. In order to utilize the datatype bits the client needs to notify the server that it supports datatype bits by performing a successful HELLO with the DATATYPE feature.
The communication is initially initiated by a request being sent from the
client to the server, and the server will respond to the request with
zero or multiple packets for each request. The client is always the
initiator of communication unless it enables the duplex
feature. When (explicitly) enabled by the client, the server may also
send requests to the client and expect a response being returned.
The command opcode defines the layout of the body of the message.
The current protocol dictates that the server won't start processing the next command until the current command is completely processed (due to the lack of barriers or any other primitives to enforce execution order). The protocol defines some "quiet commands" which won't send responses in certain cases (success for mutations, not found for gets etc). The client would know that such commands was executed when it encounters the response for the next command requested issued by the client.
The following figure illustrates the packet layout for a packet with an error message.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x01 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x09 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x4e ('N') | 0x6f ('o') | 0x74 ('t') | 0x20 (' ') |
+---------------+---------------+---------------+---------------+
28| 0x66 ('f') | 0x6f ('o') | 0x75 ('u') | 0x6e ('n') |
+---------------+---------------+---------------+---------------+
32| 0x64 ('d') |
+---------------+
Total 33 bytes (24 byte header, and 9 bytes value)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x00
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0001
Total body (8-11) : 0x00000009
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Key : None
Value (24-32): The textual string "Not found"
Request:
- MUST NOT have extras.
- MUST have key.
- MUST NOT have value.
Response (if found):
- MUST have extras.
- MAY have key.
- MAY have value.
Extra data for the get commands:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Flags |
+---------------+---------------+---------------+---------------+
Total 4 bytes
The get command gets a single key. The getq command will not send a response on a cache miss. Getk and getkq differs from get and getq by adding the key into the response packet.
Clients should implement multi-get (still important for reducing network roundtrips!) as n pipelined requests, the first n-1 being getq/getkq, the last being a regular get/getk. That way you're guaranteed to get a response, and you know when the server's done. You can also do the naive thing and send n pipelined get/getks, but then you could potentially get back a lot of "NOT_FOUND" error code packets. Alternatively, you can send 'n' getq/getkqs, followed by a 'noop' command.
To request the data associated with the key "Hello" the following fields must be specified in the packet.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x00 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x48 ('H') | 0x65 ('e') | 0x6c ('l') | 0x6c ('l') |
+---------------+---------------+---------------+---------------+
28| 0x6f ('o') |
+---------------+
Total 29 bytes (24 byte header, and 5 bytes key)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x00
Key length (2,3) : 0x0005
Extra length (4) : 0x00
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000005
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Key (24-29): The textual string: "Hello"
Value : None
If the item exist on the server the following packet is returned, otherwise a packet with status code != 0 will be returned (See Response Status)
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x04 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x09 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x01 |
+---------------+---------------+---------------+---------------+
24| 0xde | 0xad | 0xbe | 0xef |
+---------------+---------------+---------------+---------------+
28| 0x57 ('W') | 0x6f ('o') | 0x72 ('r') | 0x6c ('l') |
+---------------+---------------+---------------+---------------+
32| 0x64 ('d') |
+---------------+
Total 33 bytes (24 byte header, 4 byte extras and 5 byte value)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x00
Key length (2,3) : 0x0000
Extra length (4) : 0x04
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000009
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000001
Extras :
Flags (24-27): 0xdeadbeef
Key : None
Value (28-32): The textual string "World"
The response packet for a getk and getkq request differs from get(q) in that the key is present:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x00 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
4| 0x04 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x09 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x01 |
+---------------+---------------+---------------+---------------+
24| 0xde | 0xad | 0xbe | 0xef |
+---------------+---------------+---------------+---------------+
28| 0x48 ('H') | 0x65 ('e') | 0x6c ('l') | 0x6c ('l') |
+---------------+---------------+---------------+---------------+
32| 0x6f ('o') | 0x57 ('W') | 0x6f ('o') | 0x72 ('r') |
+---------------+---------------+---------------+---------------+
36| 0x6c ('l') | 0x64 ('d') |
+---------------+---------------+
Total 38 bytes (24 byte header, 4 byte extras, 5 byte key
and 5 byte value)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x00
Key length (2,3) : 0x0005
Extra length (4) : 0x04
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000009
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000001
Extras :
Flags (24-27): 0xdeadbeef
Key (28-32): The textual string: "Hello"
Value (33-37): The textual string: "World"
Request:
- MUST have extras.
- MUST have key.
- MAY have value.
Extra data for set/add/replace:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Flags |
+---------------+---------------+---------------+---------------+
4| Expiration |
+---------------+---------------+---------------+---------------+
Total 8 bytes
Response:
- MUST have CAS
- MUST NOT have extras
- MUST NOT have key
- MUST NOT have value
Constraints:
- If the Data Version Check (CAS) is nonzero, the requested operation MUST only succeed if the item exists and has a CAS value identical to the provided value.
- Add MUST fail if the item already exist.
- Replace MUST fail if the item doesn't exist.
- Set should store the data unconditionally if the item exists or not.
Quiet mutations only return responses on failure. Success is considered the general case and is suppressed when in quiet mode, but errors should not be allowed to go unnoticed.
The following figure shows an add-command for with key = "Hello", value = "World", flags = 0xdeadbeef and expiry: in two hours.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x02 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
4| 0x08 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x12 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0xde | 0xad | 0xbe | 0xef |
+---------------+---------------+---------------+---------------+
28| 0x00 | 0x00 | 0x0e | 0x10 |
+---------------+---------------+---------------+---------------+
32| 0x48 ('H') | 0x65 ('e') | 0x6c ('l') | 0x6c ('l') |
+---------------+---------------+---------------+---------------+
36| 0x6f ('o') | 0x57 ('W') | 0x6f ('o') | 0x72 ('r') |
+---------------+---------------+---------------+---------------+
40| 0x6c ('l') | 0x64 ('d') |
+---------------+---------------+
Total 42 bytes (24 byte header, 8 byte extras, 5 byte key and
5 byte value)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x02
Key length (2,3) : 0x0005
Extra length (4) : 0x08
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000012
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras :
Flags (24-27): 0xdeadbeef
Expiry (28-31): 0x00000e10
Key (32-36): The textual string "Hello"
Value (37-41): The textual string "World"
The result of the operation is signaled through the status code. If the command succeeds, the CAS value for the item is returned in the CAS-field of the packet:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x02 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x01 |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x02
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000000
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000001
Extras : None
Key : None
Value : None
Request:
- MUST NOT have extras.
- MUST have key.
- MUST NOT have value.
Response:
- MUST NOT have extras
- MUST NOT have key
- MUST NOT have value
Delete the item with the specific key. Quiet deletions only return responses on failure. Success is considered the general case and is suppressed when in quiet mode, but errors should not be allowed to go unnoticed.
The following figure shows a delete message for the item "Hello".
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x04 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x48 ('H') | 0x65 ('e') | 0x6c ('l') | 0x6c ('l') |
+---------------+---------------+---------------+---------------+
28| 0x6f ('o') |
+---------------+
Total 29 bytes (24 byte header, 5 byte value)
Field (offset) (value) Magic (0) : 0x80 Opcode (1) : 0x04 Key length (2,3) : 0x0005 Extra length (4) : 0x00 Data type (5) : 0x00 VBucket (6,7) : 0x0000 Total body (8-11) : 0x00000005 Opaque (12-15): 0x00000000 CAS (16-23): 0x0000000000000000 Extras : None Key : The textual string "Hello" Value : None
The result of the operation is signaled through the status code.
Request:
- MUST have extras.
- MUST have key.
- MUST NOT have value.
Extra data for incr/decr:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Amount to add / subtract |
| |
+---------------+---------------+---------------+---------------+
8| Initial value |
| |
+---------------+---------------+---------------+---------------+
16| Expiration |
+---------------+---------------+---------------+---------------+
Total 20 bytes
Response:
-
MUST NOT have extras.
-
MUST NOT have key.
-
MUST have value.
Byte/ 0 | 1 | 2 | 3 | / | | | | |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7| +---------------+---------------+---------------+---------------+ 0| 64-bit unsigned response. | | | +---------------+---------------+---------------+---------------+ Total 8 bytes
These commands will either add or remove the specified amount to the requested counter. If you want to set the value of the counter with add/set/replace, the objects data must be the ascii representation of the value and not the byte values of a 64 bit integer.
If the counter does not exist, one of two things may happen:
If the expiration value is all one-bits (0xffffffff), the operation will fail with NOT_FOUND. 2. For all other expiration values, the operation will succeed by seeding the value for this key with the provided initial value to expire with the provided expiration time. The flags will be set to zero. Decrementing a counter will never result in a "negative value" (or cause the counter to "wrap"). instead the counter is set to 0. Incrementing the counter may cause the counter to wrap.
Quiet increment / decrement only return responses on failure. Success is considered the general case and is suppressed when in quiet mode, but errors should not be allowed to go unnoticed.
The following figure shows an incr-command for key = "counter", delta = 0x01, initial = 0x00 which expires in two hours.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x05 | 0x00 | 0x07 |
+---------------+---------------+---------------+---------------+
4| 0x14 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x1b |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
28| 0x00 | 0x00 | 0x00 | 0x01 |
+---------------+---------------+---------------+---------------+
32| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
36| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
40| 0x00 | 0x00 | 0x0e | 0x10 |
+---------------+---------------+---------------+---------------+
44| 0x63 ('c') | 0x6f ('o') | 0x75 ('u') | 0x6e ('n') |
+---------------+---------------+---------------+---------------+
48| 0x74 ('t') | 0x65 ('e') | 0x72 ('r') |
+---------------+---------------+---------------+
Total 51 bytes (24 byte header, 20 byte extras, 7 byte key)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x05
Key length (2,3) : 0x0007
Extra length (4) : 0x14
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x0000001b
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras :
Delta (24-31): 0x0000000000000001
Initial (32-39): 0x0000000000000000
Expiration (40-43): 0x00000e10
Key : Textual string "counter"
Value : None
If the key doesn't exist, the server will respond with the initial value. If not the incremented value will be returned. Let's assume that the key didn't exist, so the initial value is returned:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x05 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x08 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
24| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
28| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
Total 32 bytes (24 byte header, 8 byte value)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x05
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000008
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000005
Extras : None
Key : None
Value : 0x0000000000000000
Request:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Close the connection to the server. Quiet quit should not receive a response packet.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x07 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Field (offset) (value) Magic (0) : 0x80 Opcode (1) : 0x07 Key length (2,3) : 0x0000 Extra length (4) : 0x00 Data type (5) : 0x00 VBucket (6,7) : 0x0000 Total body (8-11) : 0x00000000 Opaque (12-15): 0x00000000 CAS (16-23): 0x0000000000000000 Extras : None Key : None Value : None
The response-packet contains no extra data, and the result of the operation is signaled through the status code. The server will then close the connection.
Request:
- MAY have extras.
- MUST NOT have key.
- MUST NOT have value.
Extra data for flush:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Expiration |
+---------------+---------------+---------------+---------------+
Total 4 bytes
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Flush the items in the cache now or some time in the future as specified by the expiration field. Quiet flush only return responses on failure. Success is considered the general case and is suppressed when in quiet mode, but errors should not be allowed to go unnoticed.
Note: Is it not recommended that you flush a bucket directly with Couchbase Server (Especially with Couchbase Buckets). Instead you should instigate a flush using the Cluster Manager's REST API.
To flush the cache (delete all items) in two hours, the set the following values in the request
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x08 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x04 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x04 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x00 | 0x00 | 0x0e | 0x10 |
+---------------+---------------+---------------+---------------+
Total 28 bytes (24 byte header, 4 byte body)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x08
Key length (2,3) : 0x0000
Extra length (4) : 0x04
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000004
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras :
Expiry (24-27): 0x000e10
Key : None
Value : None
The result of the operation is signaled through the status code.
Request:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Used as a keep alive.
####Example
Noop request:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x0a | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x0a
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000000
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Key : None
Value : None
The result of the operation is signaled through the status code.
Request:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MUST have value.
Request the server version.
The server responds with a packet containing the version string in the body with the following format: "x.y.z"
Request:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x0b | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x0b
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000000
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Response:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x0b | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x31 ('1') | 0x2e ('.') | 0x33 ('3') | 0x2e ('.') |
+---------------+---------------+---------------+---------------+
28| 0x31 ('1') |
+---------------+
Total 29 bytes (24 byte header, 5 byte body)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x0b
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000005
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Key : None
Value : Textual string "1.3.1"
Request:
- MUST NOT have extras.
- MUST have key.
- MUST have value.
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
- MUST have CAS
These commands will either append or prepend the specified value to the requested key.
The following example appends '!' to the 'Hello' key.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x0e | 0x00 | 0x05 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x06 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x48 ('H') | 0x65 ('e') | 0x6c ('l') | 0x6c ('l') |
+---------------+---------------+---------------+---------------+
28| 0x6f ('o') | 0x21 ('!') |
+---------------+---------------+
Total 30 bytes (24 byte header, 5 byte key, 1 byte value)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x0e
Key length (2,3) : 0x0005
Extra length (4) : 0x00
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000006
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Key (24-28): The textual string "Hello"
Value (29) : "!"
The result of the operation is signaled through the status code.
Request:
- MUST NOT have extras.
- MAY have key.
- MUST NOT have value.
Response:
- MUST NOT have extras.
- MAY have key.
- MAY have value.
Request server statistics. Without a key specified the server will respond with a "default" set of statistics information. Each piece of statistical information is returned in its own packet (key contains the name of the statistical item and the body contains the value in ASCII format). The sequence of return packets is terminated with a packet that contains no key and no value.
The following example requests all statistics from the server
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x10 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x10
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
VBucket (6,7) : 0x0000
Total body (8-11) : 0x00000000
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Extras : None
Key : None
Value : None
The server will send each value in a separate packet with an "empty" packet no key / no value) to terminate the sequence. Each of the response packets look like the following example:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x10 | 0x00 | 0x03 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x07 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x70 ('p') | 0x69 ('i') | 0x64 ('d') | 0x33 ('3') |
+---------------+---------------+---------------+---------------+
28| 0x30 ('0') | 0x37 ('7') | 0x38 ('8') |
+---------------+---------------+---------------+
Total 31 bytes (24 byte header, 3 byte key, 4 byte body)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x10
Key length (2,3) : 0x0003
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000007
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Exstras : None
Key : The textual string "pid"
Value : The textual string "3078"
Request:
- MUST have extras.
- MUST NOT have key.
- MUST NOT have value.
Extra data for flush:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Verbosity |
+---------------+---------------+---------------+---------------+
Total 4 bytes
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MUST NOT have value.
Set the verbosity level of the server. This may cause your memcached server to generate more or less output.
To set the verbosity level to two, set the following values in the request
TODO: add me
The result of the operation is signaled through the status code.
Request:
- MUST have extras.
- MUST have key.
- MUST NOT have value.
Extra data for touch/gat:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| Expiration |
+---------------+---------------+---------------+---------------+
Total 4 bytes
Touch is used to set a new expiration time for an existing item. GAT (Get and touch) and GATQ will return the value for the object if it is present in the cache.
Example TODO: add me
The HELO command may be used to enable / disable features on the server
similar to the EHLO command in SMTP.
A well written client should identify itself by sending the HELO command
providing its name and version in the "User agent name".
Request:
- MUST NOT have extra
- SHOULD have key
- SHOULD have value
The key should contain the agent name. If the first character is '{' the server will try to parse the key as JSON and look for the following two attributes:
- "a" - which is the name of the agent
- "i" - 33 bytes connection identifier
The value should contain the various features to enable. Each feature is a two byte value in network byte order.
The following features is defined:
| Value | Feature |
|---|---|
| 0x0001 | Datatype |
| 0x0002 | TLS |
| 0x0003 | TCP Nodelay |
| 0x0004 | Mutation seqno |
| 0x0005 | TCP Delay |
| 0x0006 | XATTR |
| 0x0007 | XERROR |
| 0x0008 | Select bucket |
| 0x0009 | Collections |
| 0x000a | Snappy |
| 0x000b | JSON |
| 0x000c | Duplex |
| 0x000d | Clustermap change notification |
| 0x000e | Unordered Execution |
Datatype- The client understands the 'non-null' values in the datatype field. The server expects the client to fill in the correct values in the datatype field, and accepts that the server returns the value encoded as specified in the datatype field. This value is no longer used by the server and replaced with with individual features for the various data types to use.TLS- The client wants to TLS and send STARTTLSTCP Nodelay- The client requests the server to set TCP NODELAY on the socket used by this connection.Mutation seqno- The client requests the server to add the sequence number for a mutation to the response packet used in mutations.TCP Delay- The client requests the server to set TCP DELAY on the socket used by this connection.XATTR- The client requests the server to add XATTRs to the stream for commands where it makes sense (GetWithMeta, SetWithMeta, DcpMutation etc)XERROR- The client requests the server to send extended error codes instead of disconnecting the client when new errors occur (note that some errors may be remapped to more generic error codes instead of disconnecting)Select bucket- This is purely informational (it does not enable/disable anything on the server). It may be used from the client to know if it should be able to run select bucket or not (select bucket was a privileged command pre-spock. In spock all users may run select bucket, but only to a bucket they have access to).Collections- The client wants to enable support for CollectionsSnappy- The client wants to enable support for Snappy compression. A client with support for Snappy compression must update the datatype filed in the requests with the bit representing SNAPPY when sending snappy compressed data to the server. It must be able to receive data from the server compressed with SNAPPY identified by the bit being set in the datatype field.JSON- The client wants to enable support for JSON. The client must set this bit when storing JSON documents on the server. The server will set the appropriate bit in the datatype field when returning such documents to the client.Duplex- The client allows for full duplex on the socket. This means that the server may send requests back to the client. These messages is identified by the magic values of 0x82 (request) and 0x83 (response).Clustermap change notification- The client wants the server to notify the client with new cluster maps whenever ns_server push them to memcached. (note that this notification is subject to deduplication of the vbucket map received as part of not my vbucket)UnorderedExecution- The client allows the server to reorder the execution of commands (and send the responses in any order back to the client). Some commands can however not be reordered (select bucket being one of them), when such a command is received the server awaits all concurrent commands to complete before executing the command in isolation. Once the command is completed the server starts reordering the next commands. NOTE: It is not possible to enable unordered execution on connections used for DCP.
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MAY have value.
The server replies with all of the features the client requested that the server agreed to enable.
The following example requests all defined features from the server specifying the user agent "mchello v1.0".
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x1f | 0x00 | 0x0c |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x16 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x6d ('m') | 0x63 ('c') | 0x68 ('h') | 0x65 ('e') |
+---------------+---------------+---------------+---------------+
28| 0x6c ('l') | 0x6c ('l') | 0x6f ('o') | 0x20 (' ') |
+---------------+---------------+---------------+---------------+
32| 0x76 ('v') | 0x31 ('1') | 0x2e ('.') | 0x30 ('0') |
+---------------+---------------+---------------+---------------+
36| 0x00 | 0x01 | 0x00 | 0x02 |
+---------------+---------------+---------------+---------------+
40| 0x00 | 0x03 | 0x00 | 0x04 |
+---------------+---------------+---------------+---------------+
44| 0x00 | 0x05 |
+---------------+---------------+
Total 46 bytes (24 bytes header, 12 bytes key and 10 value)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x1f
Key length (2,3) : 0x000c
Extra length (4) : 0x00
Data type (5) : 0x00
Vbucket (6,7) : 0x0000
Total body (8-11) : 0x00000016
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Key (24-35): The textual string "mchello v1.0"
Body :
(36-37): Datatype
(38-39): TLS
(40-41): TCP NODELAY
(42-43): Mutation seqno
(44-45): TCP DELAY
The following example shows that the server agreed to enable 0x0003 and 0x0004.
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x1f | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x04 |
+---------------+---------------+---------------+---------------+
12| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x00 | 0x03 | 0x00 | 0x04 |
+---------------+---------------+---------------+---------------+
Total 28 bytes (24 bytes header and 4 value)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x1f
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0000
Total body (8-11) : 0x00000004
Opaque (12-15): 0x00000000
CAS (16-23): 0x0000000000000000
Body :
(24-25): TCP NODELAY
(26-27): Mutation seqno
TODO: add me
The list buckets command is used to list all of the buckets available
for the connection in it's current state (performing authentication may
invalidate the list).
Request:
- MUST NOT have extra
- MUST NOT have key
- MUST NOT have value
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MAY have value.
In the response packet all of the available buckets is listed and separated by a single space character.
The following example shows a successful list bucket operation.
Request:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x87 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
12| 0xef | 0xbe | 0xad | 0xde |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
Total 24 bytes
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x87 (LIST_BUCKETS)
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Vbucket (6,7) : 0x0000
Total body (8-11) : 0x00000000
Opaque (12-15): 0xefbeadde
CAS (16-23): 0x0000000000000000
Response:
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x81 | 0x87 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x1b |
+---------------+---------------+---------------+---------------+
12| 0xef | 0xbe | 0xad | 0xde |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x65 ('e') | 0x6e ('n') | 0x67 ('g') | 0x69 ('i') |
+---------------+---------------+---------------+---------------+
28| 0x6e ('n') | 0x65 ('e') | 0x65 ('e') | 0x72 ('r') |
+---------------+---------------+---------------+---------------+
32| 0x69 ('i') | 0x6e ('n') | 0x67 ('g') | 0x20 (' ') |
+---------------+---------------+---------------+---------------+
36| 0x6d ('m') | 0x61 ('a') | 0x72 ('r') | 0x6b ('k') |
+---------------+---------------+---------------+---------------+
40| 0x65 ('e') | 0x74 ('t') | 0x69 ('i') | 0x6e ('n') |
+---------------+---------------+---------------+---------------+
44| 0x67 ('g') | 0x20 (' ') | 0x73 ('s') | 0x61 ('a') |
+---------------+---------------+---------------+---------------+
48| 0x6c ('l') | 0x65 ('e') | 0x73 ('s') |
+---------------+---------------+---------------+
Total 51 bytes (24 bytes header and 27 value)
Field (offset) (value)
Magic (0) : 0x81
Opcode (1) : 0x87 (LIST_BUCKETS)
Key length (2,3) : 0x0000
Extra length (4) : 0x00
Data type (5) : 0x00
Status (6,7) : 0x0000 (Success)
Total body (8-11) : 0x0000001b
Opaque (12-15): 0xdeadbeef
CAS (16-23): 0x0000000000000000
Body :
: engineering
: marketing
: sales
The select bucket command is used to bind the connection to a given bucket
on the server.
Request:
- MUST NOT have extra
- MUST have key
- MUST NOT have value
Response:
- MUST NOT have extras.
- MUST NOT have key.
- MAY have value.
The following example tries to select the bucket named engineering
Byte/ 0 | 1 | 2 | 3 |
/ | | | |
|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+---------------+---------------+---------------+---------------+
0| 0x80 | 0x89 | 0x00 | 0x0b |
+---------------+---------------+---------------+---------------+
4| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
8| 0x00 | 0x00 | 0x00 | 0x0b |
+---------------+---------------+---------------+---------------+
12| 0xef | 0xbe | 0xad | 0xde |
+---------------+---------------+---------------+---------------+
16| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
20| 0x00 | 0x00 | 0x00 | 0x00 |
+---------------+---------------+---------------+---------------+
24| 0x65 ('e') | 0x6e ('n') | 0x67 ('g') | 0x69 ('i') |
+---------------+---------------+---------------+---------------+
28| 0x6e ('n') | 0x65 ('e') | 0x65 ('e') | 0x72 ('r') |
+---------------+---------------+---------------+---------------+
32| 0x69 ('i') | 0x6e ('n') | 0x67 ('g') |
+---------------+---------------+---------------+
Total 35 bytes (24 bytes header, 11 bytes key)
Field (offset) (value)
Magic (0) : 0x80
Opcode (1) : 0x89 (SELECT_BUCKET)
Key length (2,3) : 0x000b
Extra length (4) : 0x00
Data type (5) : 0x00
Vbucket (6,7) : 0x0000
Total body (8-11) : 0x0000000b
Opaque (12-15): 0xefbeadde
CAS (16-23): 0x0000000000000000
Key (24-34): The textual string "engineering"