| |
| CQL BINARY PROTOCOL v3 |
| |
| |
| Table of Contents |
| |
| 1. Overview |
| 2. Frame header |
| 2.1. version |
| 2.2. flags |
| 2.3. stream |
| 2.4. opcode |
| 2.5. length |
| 3. Notations |
| 4. Messages |
| 4.1. Requests |
| 4.1.1. STARTUP |
| 4.1.2. AUTH_RESPONSE |
| 4.1.3. OPTIONS |
| 4.1.4. QUERY |
| 4.1.5. PREPARE |
| 4.1.6. EXECUTE |
| 4.1.7. BATCH |
| 4.1.8. REGISTER |
| 4.2. Responses |
| 4.2.1. ERROR |
| 4.2.2. READY |
| 4.2.3. AUTHENTICATE |
| 4.2.4. SUPPORTED |
| 4.2.5. RESULT |
| 4.2.5.1. Void |
| 4.2.5.2. Rows |
| 4.2.5.3. Set_keyspace |
| 4.2.5.4. Prepared |
| 4.2.5.5. Schema_change |
| 4.2.6. EVENT |
| 4.2.7. AUTH_CHALLENGE |
| 4.2.8. AUTH_SUCCESS |
| 5. Compression |
| 6. Data Type Serialization Formats |
| 7. User Defined Type Serialization |
| 8. Result paging |
| 9. Error codes |
| 10. Changes from v2 |
| |
| |
| 1. Overview |
| |
| The CQL binary protocol is a frame based protocol. Frames are defined as: |
| |
| 0 8 16 24 32 40 |
| +---------+---------+---------+---------+---------+ |
| | version | flags | stream | opcode | |
| +---------+---------+---------+---------+---------+ |
| | length | |
| +---------+---------+---------+---------+ |
| | | |
| . ... body ... . |
| . . |
| . . |
| +---------------------------------------- |
| |
| The protocol is big-endian (network byte order). |
| |
| Each frame contains a fixed size header (9 bytes) followed by a variable size |
| body. The header is described in Section 2. The content of the body depends |
| on the header opcode value (the body can in particular be empty for some |
| opcode values). The list of allowed opcode is defined Section 2.3 and the |
| details of each corresponding message is described Section 4. |
| |
| The protocol distinguishes 2 types of frames: requests and responses. Requests |
| are those frame sent by the clients to the server, response are the ones sent |
| by the server. Note however that the protocol supports server pushes (events) |
| so responses does not necessarily come right after a client request. |
| |
| Note to client implementors: clients library should always assume that the |
| body of a given frame may contain more data than what is described in this |
| document. It will however always be safe to ignore the remaining of the frame |
| body in such cases. The reason is that this may allow to sometimes extend the |
| protocol with optional features without needing to change the protocol |
| version. |
| |
| |
| |
| 2. Frame header |
| |
| 2.1. version |
| |
| The version is a single byte that indicate both the direction of the message |
| (request or response) and the version of the protocol in use. The up-most bit |
| of version is used to define the direction of the message: 0 indicates a |
| request, 1 indicates a responses. This can be useful for protocol analyzers to |
| distinguish the nature of the packet from the direction which it is moving. |
| The rest of that byte is the protocol version (3 for the protocol defined in |
| this document). In other words, for this version of the protocol, version will |
| have one of: |
| 0x03 Request frame for this protocol version |
| 0x83 Response frame for this protocol version |
| |
| Please note that the while every message ship with the version, only one version |
| of messages is accepted on a given connection. In other words, the first message |
| exchanged (STARTUP) sets the version for the connection for the lifetime of this |
| connection. |
| |
| This document describe the version 3 of the protocol. For the changes made since |
| version 2, see Section 10. |
| |
| |
| 2.2. flags |
| |
| Flags applying to this frame. The flags have the following meaning (described |
| by the mask that allow to select them): |
| 0x01: Compression flag. If set, the frame body is compressed. The actual |
| compression to use should have been set up beforehand through the |
| Startup message (which thus cannot be compressed; Section 4.1.1). |
| 0x02: Tracing flag. For a request frame, this indicate the client requires |
| tracing of the request. Note that not all requests support tracing. |
| Currently, only QUERY, PREPARE and EXECUTE queries support tracing. |
| Other requests will simply ignore the tracing flag if set. If a |
| request support tracing and the tracing flag was set, the response to |
| this request will have the tracing flag set and contain tracing |
| information. |
| If a response frame has the tracing flag set, its body contains |
| a tracing ID. The tracing ID is a [uuid] and is the first thing in |
| the frame body. The rest of the body will then be the usual body |
| corresponding to the response opcode. |
| |
| The rest of the flags is currently unused and ignored. |
| |
| 2.3. stream |
| |
| A frame has a stream id (a [short] value). When sending request messages, this |
| stream id must be set by the client to a non-negative value (negative stream id |
| are reserved for streams initiated by the server; currently all EVENT messages |
| (section 4.2.6) have a streamId of -1). If a client sends a request message |
| with the stream id X, it is guaranteed that the stream id of the response to |
| that message will be X. |
| |
| This allow to deal with the asynchronous nature of the protocol. If a client |
| sends multiple messages simultaneously (without waiting for responses), there |
| is no guarantee on the order of the responses. For instance, if the client |
| writes REQ_1, REQ_2, REQ_3 on the wire (in that order), the server might |
| respond to REQ_3 (or REQ_2) first. Assigning different stream id to these 3 |
| requests allows the client to distinguish to which request an received answer |
| respond to. As there can only be 32768 different simultaneous streams, it is up |
| to the client to reuse stream id. |
| |
| Note that clients are free to use the protocol synchronously (i.e. wait for |
| the response to REQ_N before sending REQ_N+1). In that case, the stream id |
| can be safely set to 0. Clients should also feel free to use only a subset of |
| the 32768 maximum possible stream ids if it is simpler for those |
| implementation. |
| |
| 2.4. opcode |
| |
| An integer byte that distinguish the actual message: |
| 0x00 ERROR |
| 0x01 STARTUP |
| 0x02 READY |
| 0x03 AUTHENTICATE |
| 0x05 OPTIONS |
| 0x06 SUPPORTED |
| 0x07 QUERY |
| 0x08 RESULT |
| 0x09 PREPARE |
| 0x0A EXECUTE |
| 0x0B REGISTER |
| 0x0C EVENT |
| 0x0D BATCH |
| 0x0E AUTH_CHALLENGE |
| 0x0F AUTH_RESPONSE |
| 0x10 AUTH_SUCCESS |
| |
| Messages are described in Section 4. |
| |
| (Note that there is no 0x04 message in this version of the protocol) |
| |
| |
| 2.5. length |
| |
| A 4 byte integer representing the length of the body of the frame (note: |
| currently a frame is limited to 256MB in length). |
| |
| |
| 3. Notations |
| |
| To describe the layout of the frame body for the messages in Section 4, we |
| define the following: |
| |
| [int] A 4 bytes signed integer |
| [long] A 8 bytes signed integer |
| [short] A 2 bytes unsigned integer |
| [string] A [short] n, followed by n bytes representing an UTF-8 |
| string. |
| [long string] An [int] n, followed by n bytes representing an UTF-8 string. |
| [uuid] A 16 bytes long uuid. |
| [string list] A [short] n, followed by n [string]. |
| [bytes] A [int] n, followed by n bytes if n >= 0. If n < 0, |
| no byte should follow and the value represented is `null`. |
| [short bytes] A [short] n, followed by n bytes if n >= 0. |
| |
| [option] A pair of <id><value> where <id> is a [short] representing |
| the option id and <value> depends on that option (and can be |
| of size 0). The supported id (and the corresponding <value>) |
| will be described when this is used. |
| [option list] A [short] n, followed by n [option]. |
| [inet] An address (ip and port) to a node. It consists of one |
| [byte] n, that represents the address size, followed by n |
| [byte] representing the IP address (in practice n can only be |
| either 4 (IPv4) or 16 (IPv6)), following by one [int] |
| representing the port. |
| [consistency] A consistency level specification. This is a [short] |
| representing a consistency level with the following |
| correspondance: |
| 0x0000 ANY |
| 0x0001 ONE |
| 0x0002 TWO |
| 0x0003 THREE |
| 0x0004 QUORUM |
| 0x0005 ALL |
| 0x0006 LOCAL_QUORUM |
| 0x0007 EACH_QUORUM |
| 0x0008 SERIAL |
| 0x0009 LOCAL_SERIAL |
| 0x000A LOCAL_ONE |
| |
| [string map] A [short] n, followed by n pair <k><v> where <k> and <v> |
| are [string]. |
| [string multimap] A [short] n, followed by n pair <k><v> where <k> is a |
| [string] and <v> is a [string list]. |
| |
| |
| 4. Messages |
| |
| 4.1. Requests |
| |
| Note that outside of their normal responses (described below), all requests |
| can get an ERROR message (Section 4.2.1) as response. |
| |
| 4.1.1. STARTUP |
| |
| Initialize the connection. The server will respond by either a READY message |
| (in which case the connection is ready for queries) or an AUTHENTICATE message |
| (in which case credentials will need to be provided using AUTH_RESPONSE). |
| |
| This must be the first message of the connection, except for OPTIONS that can |
| be sent before to find out the options supported by the server. Once the |
| connection has been initialized, a client should not send any more STARTUP |
| message. |
| |
| The body is a [string map] of options. Possible options are: |
| - "CQL_VERSION": the version of CQL to use. This option is mandatory and |
| currenty, the only version supported is "3.0.0". Note that this is |
| different from the protocol version. |
| - "COMPRESSION": the compression algorithm to use for frames (See section 5). |
| This is optional, if not specified no compression will be used. |
| |
| |
| 4.1.2. AUTH_RESPONSE |
| |
| Answers a server authentication challenge. |
| |
| Authentication in the protocol is SASL based. The server sends authentication |
| challenges (a bytes token) to which the client answer with this message. Those |
| exchanges continue until the server accepts the authentication by sending a |
| AUTH_SUCCESS message after a client AUTH_RESPONSE. It is however that client that |
| initiate the exchange by sending an initial AUTH_RESPONSE in response to a |
| server AUTHENTICATE request. |
| |
| The body of this message is a single [bytes] token. The details of what this |
| token contains (and when it can be null/empty, if ever) depends on the actual |
| authenticator used. |
| |
| The response to a AUTH_RESPONSE is either a follow-up AUTH_CHALLENGE message, |
| an AUTH_SUCCESS message or an ERROR message. |
| |
| |
| 4.1.3. OPTIONS |
| |
| Asks the server to return what STARTUP options are supported. The body of an |
| OPTIONS message should be empty and the server will respond with a SUPPORTED |
| message. |
| |
| |
| 4.1.4. QUERY |
| |
| Performs a CQL query. The body of the message must be: |
| <query><query_parameters> |
| where <query> is a [long string] representing the query and |
| <query_parameters> must be |
| <consistency><flags>[<n>[name_1]<value_1>...[name_n]<value_n>][<result_page_size>][<paging_state>][<serial_consistency>][<timestamp>] |
| where: |
| - <consistency> is the [consistency] level for the operation. |
| - <flags> is a [byte] whose bits define the options for this query and |
| in particular influence what the remainder of the message contains. |
| A flag is set if the bit corresponding to its `mask` is set. Supported |
| flags are, given there mask: |
| 0x01: Values. In that case, a [short] <n> followed by <n> [bytes] |
| values are provided. Those value are used for bound variables in |
| the query. Optionally, if the 0x40 flag is present, each value |
| will be preceded by a [string] name, representing the name of |
| the marker the value must be binded to. This is optional, and |
| if not present, values will be binded by position. |
| 0x02: Skip_metadata. If present, the Result Set returned as a response |
| to that query (if any) will have the NO_METADATA flag (see |
| Section 4.2.5.2). |
| 0x04: Page_size. In that case, <result_page_size> is an [int] |
| controlling the desired page size of the result (in CQL3 rows). |
| See the section on paging (Section 8) for more details. |
| 0x08: With_paging_state. If present, <paging_state> should be present. |
| <paging_state> is a [bytes] value that should have been returned |
| in a result set (Section 4.2.5.2). If provided, the query will be |
| executed but starting from a given paging state. This also to |
| continue paging on a different node from the one it has been |
| started (See Section 8 for more details). |
| 0x10: With serial consistency. If present, <serial_consistency> should be |
| present. <serial_consistency> is the [consistency] level for the |
| serial phase of conditional updates. That consitency can only be |
| either SERIAL or LOCAL_SERIAL and if not present, it defaults to |
| SERIAL. This option will be ignored for anything else that a |
| conditional update/insert. |
| 0x20: With default timestamp. If present, <timestamp> should be present. |
| <timestamp> is a [long] representing the default timestamp for the query |
| in microseconds (negative values are discouraged but supported for |
| backward compatibility reasons except for the smallest negative |
| value (-2^63) that is forbidden). If provided, this will |
| replace the server side assigned timestamp as default timestamp. |
| Note that a timestamp in the query itself will still override |
| this timestamp. This is entirely optional. |
| 0x40: With names for values. This only makes sense if the 0x01 flag is set and |
| is ignored otherwise. If present, the values from the 0x01 flag will |
| be preceded by a name (see above). Note that this is only useful for |
| QUERY requests where named bind markers are used; for EXECUTE statements, |
| since the names for the expected values was returned during preparation, |
| a client can always provide values in the right order without any names |
| and using this flag, while supported, is almost surely inefficient. |
| |
| Note that the consistency is ignored by some queries (USE, CREATE, ALTER, |
| TRUNCATE, ...). |
| |
| The server will respond to a QUERY message with a RESULT message, the content |
| of which depends on the query. |
| |
| |
| 4.1.5. PREPARE |
| |
| Prepare a query for later execution (through EXECUTE). The body consists of |
| the CQL query to prepare as a [long string]. |
| |
| The server will respond with a RESULT message with a `prepared` kind (0x0004, |
| see Section 4.2.5). |
| |
| |
| 4.1.6. EXECUTE |
| |
| Executes a prepared query. The body of the message must be: |
| <id><query_parameters> |
| where <id> is the prepared query ID. It's the [short bytes] returned as a |
| response to a PREPARE message. As for <query_parameters>, it has the exact |
| same definition than in QUERY (see Section 4.1.4). |
| |
| The response from the server will be a RESULT message. |
| |
| |
| 4.1.7. BATCH |
| |
| Allows executing a list of queries (prepared or not) as a batch (note that |
| only DML statements are accepted in a batch). The body of the message must |
| be: |
| <type><n><query_1>...<query_n><consistency><flags>[<serial_consistency>][<timestamp>] |
| where: |
| - <type> is a [byte] indicating the type of batch to use: |
| - If <type> == 0, the batch will be "logged". This is equivalent to a |
| normal CQL3 batch statement. |
| - If <type> == 1, the batch will be "unlogged". |
| - If <type> == 2, the batch will be a "counter" batch (and non-counter |
| statements will be rejected). |
| - <flags> is a [byte] whose bits define the options for this query and |
| in particular influence the remainder of the message contains. It is similar |
| to the <flags> from QUERY and EXECUTE methods, except that the 4 rightmost |
| bits must always be 0 as their corresponding option do not make sense for |
| Batch. A flag is set if the bit corresponding to its `mask` is set. Supported |
| flags are, given there mask: |
| 0x10: With serial consistency. If present, <serial_consistency> should be |
| present. <serial_consistency> is the [consistency] level for the |
| serial phase of conditional updates. That consitency can only be |
| either SERIAL or LOCAL_SERIAL and if not present, it defaults to |
| SERIAL. This option will be ignored for anything else that a |
| conditional update/insert. |
| 0x20: With default timestamp. If present, <timestamp> should be present. |
| <timestamp> is a [long] representing the default timestamp for the query |
| in microseconds. If provided, this will replace the server side assigned |
| timestamp as default timestamp. Note that a timestamp in the query itself |
| will still override this timestamp. This is entirely optional. |
| 0x40: With names for values. If set, then all values for all <query_i> must be |
| preceded by a [string] <name_i> that have the same meaning as in QUERY |
| requests [IMPORTANT NOTE: this feature does not work and should not be |
| used. It is specified in a way that makes it impossible for the server |
| to implement. This will be fixed in a future version of the native |
| protocol. See https://issues.apache.org/jira/browse/CASSANDRA-10246 for |
| more details]. |
| - <n> is a [short] indicating the number of following queries. |
| - <query_1>...<query_n> are the queries to execute. A <query_i> must be of the |
| form: |
| <kind><string_or_id><n>[<name_1>]<value_1>...[<name_n>]<value_n> |
| where: |
| - <kind> is a [byte] indicating whether the following query is a prepared |
| one or not. <kind> value must be either 0 or 1. |
| - <string_or_id> depends on the value of <kind>. If <kind> == 0, it should be |
| a [long string] query string (as in QUERY, the query string might contain |
| bind markers). Otherwise (that is, if <kind> == 1), it should be a |
| [short bytes] representing a prepared query ID. |
| - <n> is a [short] indicating the number (possibly 0) of following values. |
| - <name_i> is the optional name of the following <value_i>. It must be present |
| if and only if the 0x40 flag is provided for the batch. |
| - <value_i> is the [bytes] to use for bound variable i (of bound variable <name_i> |
| if the 0x40 flag is used). |
| - <consistency> is the [consistency] level for the operation. |
| - <serial_consistency> is only present if the 0x10 flag is set. In that case, |
| <serial_consistency> is the [consistency] level for the serial phase of |
| conditional updates. That consitency can only be either SERIAL or |
| LOCAL_SERIAL and if not present will defaults to SERIAL. This option will |
| be ignored for anything else that a conditional update/insert. |
| |
| The server will respond with a RESULT message. |
| |
| |
| 4.1.8. REGISTER |
| |
| Register this connection to receive some type of events. The body of the |
| message is a [string list] representing the event types to register to. See |
| section 4.2.6 for the list of valid event types. |
| |
| The response to a REGISTER message will be a READY message. |
| |
| Please note that if a client driver maintains multiple connections to a |
| Cassandra node and/or connections to multiple nodes, it is advised to |
| dedicate a handful of connections to receive events, but to *not* register |
| for events on all connections, as this would only result in receiving |
| multiple times the same event messages, wasting bandwidth. |
| |
| |
| 4.2. Responses |
| |
| This section describes the content of the frame body for the different |
| responses. Please note that to make room for future evolution, clients should |
| support extra informations (that they should simply discard) to the one |
| described in this document at the end of the frame body. |
| |
| 4.2.1. ERROR |
| |
| Indicates an error processing a request. The body of the message will be an |
| error code ([int]) followed by a [string] error message. Then, depending on |
| the exception, more content may follow. The error codes are defined in |
| Section 9, along with their additional content if any. |
| |
| |
| 4.2.2. READY |
| |
| Indicates that the server is ready to process queries. This message will be |
| sent by the server either after a STARTUP message if no authentication is |
| required, or after a successful CREDENTIALS message. |
| |
| The body of a READY message is empty. |
| |
| |
| 4.2.3. AUTHENTICATE |
| |
| Indicates that the server require authentication, and which authentication |
| mechanism to use. |
| |
| The authentication is SASL based and thus consists on a number of server |
| challenges (AUTH_CHALLENGE, Section 4.2.7) followed by client responses |
| (AUTH_RESPONSE, Section 4.1.2). The Initial exchange is however boostrapped |
| by an initial client response. The details of that exchange (including how |
| much challenge-response pair are required) are specific to the authenticator |
| in use. The exchange ends when the server sends an AUTH_SUCCESS message or |
| an ERROR message. |
| |
| This message will be sent following a STARTUP message if authentication is |
| required and must be answered by a AUTH_RESPONSE message from the client. |
| |
| The body consists of a single [string] indicating the full class name of the |
| IAuthenticator in use. |
| |
| |
| 4.2.4. SUPPORTED |
| |
| Indicates which startup options are supported by the server. This message |
| comes as a response to an OPTIONS message. |
| |
| The body of a SUPPORTED message is a [string multimap]. This multimap gives |
| for each of the supported STARTUP options, the list of supported values. |
| |
| |
| 4.2.5. RESULT |
| |
| The result to a query (QUERY, PREPARE, EXECUTE or BATCH messages). |
| |
| The first element of the body of a RESULT message is an [int] representing the |
| `kind` of result. The rest of the body depends on the kind. The kind can be |
| one of: |
| 0x0001 Void: for results carrying no information. |
| 0x0002 Rows: for results to select queries, returning a set of rows. |
| 0x0003 Set_keyspace: the result to a `use` query. |
| 0x0004 Prepared: result to a PREPARE message. |
| 0x0005 Schema_change: the result to a schema altering query. |
| |
| The body for each kind (after the [int] kind) is defined below. |
| |
| |
| 4.2.5.1. Void |
| |
| The rest of the body for a Void result is empty. It indicates that a query was |
| successful without providing more information. |
| |
| |
| 4.2.5.2. Rows |
| |
| Indicates a set of rows. The rest of body of a Rows result is: |
| <metadata><rows_count><rows_content> |
| where: |
| - <metadata> is composed of: |
| <flags><columns_count>[<paging_state>][<global_table_spec>?<col_spec_1>...<col_spec_n>] |
| where: |
| - <flags> is an [int]. The bits of <flags> provides information on the |
| formatting of the remaining informations. A flag is set if the bit |
| corresponding to its `mask` is set. Supported flags are, given there |
| mask: |
| 0x0001 Global_tables_spec: if set, only one table spec (keyspace |
| and table name) is provided as <global_table_spec>. If not |
| set, <global_table_spec> is not present. |
| 0x0002 Has_more_pages: indicates whether this is not the last |
| page of results and more should be retrieve. If set, the |
| <paging_state> will be present. The <paging_state> is a |
| [bytes] value that should be used in QUERY/EXECUTE to |
| continue paging and retrieve the remained of the result for |
| this query (See Section 8 for more details). |
| 0x0004 No_metadata: if set, the <metadata> is only composed of |
| these <flags>, the <column_count> and optionally the |
| <paging_state> (depending on the Has_more_pages flage) but |
| no other information (so no <global_table_spec> nor <col_spec_i>). |
| This will only ever be the case if this was requested |
| during the query (see QUERY and RESULT messages). |
| - <columns_count> is an [int] representing the number of columns selected |
| by the query this result is of. It defines the number of <col_spec_i> |
| elements in and the number of element for each row in <rows_content>. |
| - <global_table_spec> is present if the Global_tables_spec is set in |
| <flags>. If present, it is composed of two [string] representing the |
| (unique) keyspace name and table name the columns return are of. |
| - <col_spec_i> specifies the columns returned in the query. There is |
| <column_count> such column specifications that are composed of: |
| (<ksname><tablename>)?<name><type> |
| The initial <ksname> and <tablename> are two [string] are only present |
| if the Global_tables_spec flag is not set. The <column_name> is a |
| [string] and <type> is an [option] that correspond to the description |
| (what this description is depends a bit on the context: in results to |
| selects, this will be either the user chosen alias or the selection used |
| (often a colum name, but it can be a function call too). In results to |
| a PREPARE, this will be either the name of the bind variable corresponding |
| or the column name for the variable if it is "anonymous") and type of |
| the corresponding result. The option for <type> is either a native |
| type (see below), in which case the option has no value, or a |
| 'custom' type, in which case the value is a [string] representing |
| the full qualified class name of the type represented. Valid option |
| ids are: |
| 0x0000 Custom: the value is a [string], see above. |
| 0x0001 Ascii |
| 0x0002 Bigint |
| 0x0003 Blob |
| 0x0004 Boolean |
| 0x0005 Counter |
| 0x0006 Decimal |
| 0x0007 Double |
| 0x0008 Float |
| 0x0009 Int |
| 0x000B Timestamp |
| 0x000C Uuid |
| 0x000D Varchar |
| 0x000E Varint |
| 0x000F Timeuuid |
| 0x0010 Inet |
| 0x0020 List: the value is an [option], representing the type |
| of the elements of the list. |
| 0x0021 Map: the value is two [option], representing the types of the |
| keys and values of the map |
| 0x0022 Set: the value is an [option], representing the type |
| of the elements of the set |
| 0x0030 UDT: the value is <ks><udt_name><n><name_1><type_1>...<name_n><type_n> |
| where: |
| - <ks> is a [string] representing the keyspace name this |
| UDT is part of. |
| - <udt_name> is a [string] representing the UDT name. |
| - <n> is a [short] reprensenting the number of fields of |
| the UDT, and thus the number of <name_i><type_i> pair |
| following |
| - <name_i> is a [string] representing the name of the |
| i_th field of the UDT. |
| - <type_i> is an [option] representing the type of the |
| i_th field of the UDT. |
| 0x0031 Tuple: the value is <n><type_1>...<type_n> where <n> is a [short] |
| representing the number of value in the type, and <type_i> |
| are [option] representing the type of the i_th component |
| of the tuple |
| |
| - <rows_count> is an [int] representing the number of rows present in this |
| result. Those rows are serialized in the <rows_content> part. |
| - <rows_content> is composed of <row_1>...<row_m> where m is <rows_count>. |
| Each <row_i> is composed of <value_1>...<value_n> where n is |
| <columns_count> and where <value_j> is a [bytes] representing the value |
| returned for the jth column of the ith row. In other words, <rows_content> |
| is composed of (<rows_count> * <columns_count>) [bytes]. |
| |
| |
| 4.2.5.3. Set_keyspace |
| |
| The result to a `use` query. The body (after the kind [int]) is a single |
| [string] indicating the name of the keyspace that has been set. |
| |
| |
| 4.2.5.4. Prepared |
| |
| The result to a PREPARE message. The rest of the body of a Prepared result is: |
| <id><metadata><result_metadata> |
| where: |
| - <id> is [short bytes] representing the prepared query ID. |
| - <metadata> is defined exactly as for a Rows RESULT (See section 4.2.5.2; you |
| can however assume that the Has_more_pages flag is always off) and |
| is the specification for the variable bound in this prepare statement. |
| - <result_metadata> is defined exactly as <metadata> but correspond to the |
| metadata for the resultSet that execute this query will yield. Note that |
| <result_metadata> may be empty (have the No_metadata flag and 0 columns, See |
| section 4.2.5.2) and will be for any query that is not a Select. There is |
| in fact never a guarantee that this will non-empty so client should protect |
| themselves accordingly. The presence of this information is an |
| optimization that allows to later execute the statement that has been |
| prepared without requesting the metadata (Skip_metadata flag in EXECUTE). |
| Clients can safely discard this metadata if they do not want to take |
| advantage of that optimization. |
| |
| Note that prepared query ID return is global to the node on which the query |
| has been prepared. It can be used on any connection to that node and this |
| until the node is restarted (after which the query must be reprepared). |
| |
| 4.2.5.5. Schema_change |
| |
| The result to a schema altering query (creation/update/drop of a |
| keyspace/table/index). The body (after the kind [int]) is the same |
| as the body for a "SCHEMA_CHANGE" event, so 3 strings: |
| <change_type><target><options> |
| Please refer to the section 4.2.6 below for the meaning of those fields. |
| |
| Note that queries to create and drop an index are considered as change |
| updating the table the index is on. |
| |
| |
| 4.2.6. EVENT |
| |
| And event pushed by the server. A client will only receive events for the |
| type it has REGISTER to. The body of an EVENT message will start by a |
| [string] representing the event type. The rest of the message depends on the |
| event type. The valid event types are: |
| - "TOPOLOGY_CHANGE": events related to change in the cluster topology. |
| Currently, events are sent when new nodes are added to the cluster, and |
| when nodes are removed. The body of the message (after the event type) |
| consists of a [string] and an [inet], corresponding respectively to the |
| type of change ("NEW_NODE", "REMOVED_NODE", or "MOVED_NODE") followed |
| by the address of the new/removed/moved node. |
| - "STATUS_CHANGE": events related to change of node status. Currently, |
| up/down events are sent. The body of the message (after the event type) |
| consists of a [string] and an [inet], corresponding respectively to the |
| type of status change ("UP" or "DOWN") followed by the address of the |
| concerned node. |
| - "SCHEMA_CHANGE": events related to schema change. After the event type, |
| the rest of the message will be <change_type><target><options> where: |
| - <change_type> is a [string] representing the type of changed involved. |
| It will be one of "CREATED", "UPDATED" or "DROPPED". |
| - <target> is a [string] that can be one of "KEYSPACE", "TABLE" or "TYPE" |
| and describes what has been modified ("TYPE" stands for modifications |
| related to user types). |
| - <options> depends on the preceding <target>. If <target> is |
| "KEYSPACE", then <options> will be a single [string] representing the |
| keyspace changed. Otherwise, if <target> is "TABLE" or "TYPE", then |
| <options> will be 2 [string]: the first one will be the keyspace |
| containing the affected object, and the second one will be the name |
| of said affected object (so either the table name or the user type |
| name). |
| |
| All EVENT message have a streamId of -1 (Section 2.3). |
| |
| Please note that "NEW_NODE" and "UP" events are sent based on internal Gossip |
| communication and as such may be sent a short delay before the binary |
| protocol server on the newly up node is fully started. Clients are thus |
| advise to wait a short time before trying to connect to the node (1 seconds |
| should be enough), otherwise they may experience a connection refusal at |
| first. |
| |
| It is possible for the same event to be sent multiple times. Therefore, |
| a client library should ignore the same event if it has already been notified |
| of a change. |
| |
| 4.2.7. AUTH_CHALLENGE |
| |
| A server authentication challenge (see AUTH_RESPONSE (Section 4.1.2) for more |
| details). |
| |
| The body of this message is a single [bytes] token. The details of what this |
| token contains (and when it can be null/empty, if ever) depends on the actual |
| authenticator used. |
| |
| Clients are expected to answer the server challenge by an AUTH_RESPONSE |
| message. |
| |
| 4.2.7. AUTH_SUCCESS |
| |
| Indicate the success of the authentication phase. See Section 4.2.3 for more |
| details. |
| |
| The body of this message is a single [bytes] token holding final information |
| from the server that the client may require to finish the authentication |
| process. What that token contains and whether it can be null depends on the |
| actual authenticator used. |
| |
| |
| 5. Compression |
| |
| Frame compression is supported by the protocol, but then only the frame body |
| is compressed (the frame header should never be compressed). |
| |
| Before being used, client and server must agree on a compression algorithm to |
| use, which is done in the STARTUP message. As a consequence, a STARTUP message |
| must never be compressed. However, once the STARTUP frame has been received |
| by the server can be compressed (including the response to the STARTUP |
| request). Frame do not have to be compressed however, even if compression has |
| been agreed upon (a server may only compress frame above a certain size at its |
| discretion). A frame body should be compressed if and only if the compressed |
| flag (see Section 2.2) is set. |
| |
| As of this version 2 of the protocol, the following compressions are available: |
| - lz4 (https://code.google.com/p/lz4/). In that, note that the 4 first bytes |
| of the body will be the uncompressed length (followed by the compressed |
| bytes). |
| - snappy (https://code.google.com/p/snappy/). This compression might not be |
| available as it depends on a native lib (server-side) that might not be |
| avaivable on some installation. |
| |
| |
| 6. Data Type Serialization Formats |
| |
| This sections describes the serialization formats for all CQL data types |
| supported by Cassandra through the native protocol. These serialization |
| formats should be used by client drivers to encode values for EXECUTE |
| messages. Cassandra will use these formats when returning values in |
| RESULT messages. |
| |
| All values are represented as [bytes] in EXECUTE and RESULT messages. |
| The [bytes] format includes an int prefix denoting the length of the value. |
| For that reason, the serialization formats described here will not include |
| a length component. |
| |
| For legacy compatibility reasons, note that most non-string types support |
| "empty" values (i.e. a value with zero length). An empty value is distinct |
| from NULL, which is encoded with a negative length. |
| |
| As with the rest of the native protocol, all encodings are big-endian. |
| |
| 6.1. ascii |
| |
| A sequence of bytes in the ASCII range [0, 127]. Bytes with values outside of |
| this range will result in a validation error. |
| |
| 6.2 bigint |
| |
| An eight-byte two's complement integer. |
| |
| 6.3 blob |
| |
| Any sequence of bytes. |
| |
| 6.4 boolean |
| |
| A single byte. A value of 0 denotes "false"; any other value denotes "true". |
| (However, it is recommended that a value of 1 be used to represent "true".) |
| |
| 6.5 decimal |
| |
| The decimal format represents an arbitrary-precision number. It contains an |
| [int] "scale" component followed by a varint encoding (see section 6.17) |
| of the unscaled value. The encoded value represents "<unscaled>E<-scale>". |
| In other words, "<unscaled> * 10 ^ (-1 * <scale>)". |
| |
| 6.6 double |
| |
| An eight-byte floating point number in the IEEE 754 binary64 format. |
| |
| 6.7 float |
| |
| An four-byte floating point number in the IEEE 754 binary32 format. |
| |
| 6.8 inet |
| |
| A 4 byte or 16 byte sequence denoting an IPv4 or IPv6 address, respectively. |
| |
| 6.9 int |
| |
| A four-byte two's complement integer. |
| |
| 6.10 list |
| |
| A [int] n indicating the number of elements in the list, followed by n |
| elements. Each element is [bytes] representing the serialized value. |
| |
| 6.11 map |
| |
| A [int] n indicating the number of key/value pairs in the map, followed by |
| n entries. Each entry is composed of two [bytes] representing the key |
| and value. |
| |
| 6.12 set |
| |
| A [int] n indicating the number of elements in the set, followed by n |
| elements. Each element is [bytes] representing the serialized value. |
| |
| 6.13 text |
| |
| A sequence of bytes conforming to the UTF-8 specifications. |
| |
| 6.14 timestamp |
| |
| An eight-byte two's complement integer representing a millisecond-precision |
| offset from the unix epoch (00:00:00, January 1st, 1970). Negative values |
| represent a negative offset from the epoch. |
| |
| 6.15 uuid |
| |
| A 16 byte sequence representing any valid UUID as defined by RFC 4122. |
| |
| 6.16 varchar |
| |
| An alias of the "text" type. |
| |
| 6.17 varint |
| |
| A variable-length two's complement encoding of a signed integer. |
| |
| The following examples may help implementors of this spec: |
| |
| Value | Encoding |
| ------|--------- |
| 0 | 0x00 |
| 1 | 0x01 |
| 127 | 0x7F |
| 128 | 0x0080 |
| 129 | 0x0081 |
| -1 | 0xFF |
| -128 | 0x80 |
| -129 | 0xFF7F |
| |
| Note that positive numbers must use a most-significant byte with a value |
| less than 0x80, because a most-significant bit of 1 indicates a negative |
| value. Implementors should pad positive values that have a MSB >= 0x80 |
| with a leading 0x00 byte. |
| |
| 6.18 timeuuid |
| |
| A 16 byte sequence representing a version 1 UUID as defined by RFC 4122. |
| |
| 6.19 tuple |
| |
| A sequence of [bytes] values representing the items in a tuple. The encoding |
| of each element depends on the data type for that position in the tuple. |
| Null values may be represented by using length -1 for the [bytes] |
| representation of an element. |
| |
| Within a tuple, all data types should use the v3 protocol serialization format. |
| |
| |
| 7. User Defined Types |
| |
| This section describes the serialization format for User defined types (UDT), |
| as described in section 4.2.5.2. |
| |
| A UDT value is composed of successive [bytes] values, one for each field of the UDT |
| value (in the order defined by the type). A UDT value will generally have one value |
| for each field of the type it represents, but it is allowed to have less values than |
| the type has fields. |
| |
| Within a user-defined type value, all data types should use the v3 protocol |
| serialization format. |
| |
| |
| 8. Result paging |
| |
| The protocol allows for paging the result of queries. For that, the QUERY and |
| EXECUTE messages have a <result_page_size> value that indicate the desired |
| page size in CQL3 rows. |
| |
| If a positive value is provided for <result_page_size>, the result set of the |
| RESULT message returned for the query will contain at most the |
| <result_page_size> first rows of the query result. If that first page of result |
| contains the full result set for the query, the RESULT message (of kind `Rows`) |
| will have the Has_more_pages flag *not* set. However, if some results are not |
| part of the first response, the Has_more_pages flag will be set and the result |
| will contain a <paging_state> value. In that case, the <paging_state> value |
| should be used in a QUERY or EXECUTE message (that has the *same* query than |
| the original one or the behavior is undefined) to retrieve the next page of |
| results. |
| |
| Only CQL3 queries that return a result set (RESULT message with a Rows `kind`) |
| support paging. For other type of queries, the <result_page_size> value is |
| ignored. |
| |
| Note to client implementors: |
| - While <result_page_size> can be as low as 1, it will likely be detrimental |
| to performance to pick a value too low. A value below 100 is probably too |
| low for most use cases. |
| - Clients should not rely on the actual size of the result set returned to |
| decide if there is more result to fetch or not. Instead, they should always |
| check the Has_more_pages flag (unless they did not enabled paging for the query |
| obviously). Clients should also not assert that no result will have more than |
| <result_page_size> results. While the current implementation always respect |
| the exact value of <result_page_size>, we reserve ourselves the right to return |
| slightly smaller or bigger pages in the future for performance reasons. |
| |
| |
| 9. Error codes |
| |
| The supported error codes are described below: |
| 0x0000 Server error: something unexpected happened. This indicates a |
| server-side bug. |
| 0x000A Protocol error: some client message triggered a protocol |
| violation (for instance a QUERY message is sent before a STARTUP |
| one has been sent) |
| 0x0100 Bad credentials: CREDENTIALS request failed because Cassandra |
| did not accept the provided credentials. |
| |
| 0x1000 Unavailable exception. The rest of the ERROR message body will be |
| <cl><required><alive> |
| where: |
| <cl> is the [consistency] level of the query having triggered |
| the exception. |
| <required> is an [int] representing the number of node that |
| should be alive to respect <cl> |
| <alive> is an [int] representing the number of replica that |
| were known to be alive when the request has been |
| processed (since an unavailable exception has been |
| triggered, there will be <alive> < <required>) |
| 0x1001 Overloaded: the request cannot be processed because the |
| coordinator node is overloaded |
| 0x1002 Is_bootstrapping: the request was a read request but the |
| coordinator node is bootstrapping |
| 0x1003 Truncate_error: error during a truncation error. |
| 0x1100 Write_timeout: Timeout exception during a write request. The rest |
| of the ERROR message body will be |
| <cl><received><blockfor><writeType> |
| where: |
| <cl> is the [consistency] level of the query having triggered |
| the exception. |
| <received> is an [int] representing the number of nodes having |
| acknowledged the request. |
| <blockfor> is an [int] representing the number of replica whose |
| acknowledgement is required to achieve <cl>. |
| <writeType> is a [string] that describe the type of the write |
| that timeouted. The value of that string can be one |
| of: |
| - "SIMPLE": the write was a non-batched |
| non-counter write. |
| - "BATCH": the write was a (logged) batch write. |
| If this type is received, it means the batch log |
| has been successfully written (otherwise a |
| "BATCH_LOG" type would have been send instead). |
| - "UNLOGGED_BATCH": the write was an unlogged |
| batch. Not batch log write has been attempted. |
| - "COUNTER": the write was a counter write |
| (batched or not). |
| - "BATCH_LOG": the timeout occured during the |
| write to the batch log when a (logged) batch |
| write was requested. |
| 0x1200 Read_timeout: Timeout exception during a read request. The rest |
| of the ERROR message body will be |
| <cl><received><blockfor><data_present> |
| where: |
| <cl> is the [consistency] level of the query having triggered |
| the exception. |
| <received> is an [int] representing the number of nodes having |
| answered the request. |
| <blockfor> is an [int] representing the number of replica whose |
| response is required to achieve <cl>. Please note that |
| it is possible to have <received> >= <blockfor> if |
| <data_present> is false. And also in the (unlikely) |
| case were <cl> is achieved but the coordinator node |
| timeout while waiting for read-repair |
| acknowledgement. |
| <data_present> is a single byte. If its value is 0, it means |
| the replica that was asked for data has not |
| responded. Otherwise, the value is != 0. |
| |
| 0x2000 Syntax_error: The submitted query has a syntax error. |
| 0x2100 Unauthorized: The logged user doesn't have the right to perform |
| the query. |
| 0x2200 Invalid: The query is syntactically correct but invalid. |
| 0x2300 Config_error: The query is invalid because of some configuration issue |
| 0x2400 Already_exists: The query attempted to create a keyspace or a |
| table that was already existing. The rest of the ERROR message |
| body will be <ks><table> where: |
| <ks> is a [string] representing either the keyspace that |
| already exists, or the keyspace in which the table that |
| already exists is. |
| <table> is a [string] representing the name of the table that |
| already exists. If the query was attempting to create a |
| keyspace, <table> will be present but will be the empty |
| string. |
| 0x2500 Unprepared: Can be thrown while a prepared statement tries to be |
| executed if the provide prepared statement ID is not known by |
| this host. The rest of the ERROR message body will be [short |
| bytes] representing the unknown ID. |
| |
| 10. Changes from v2 |
| * stream id is now 2 bytes long (a [short] value), so the header is now 1 byte longer (9 bytes total). |
| * BATCH messages now have <flags> (like QUERY and EXECUTE) and a corresponding optional |
| <serial_consistency> parameters (see Section 4.1.7). |
| * User Defined Types and tuple types have to added to ResultSet metadata (see 4.2.5.2) and a |
| new section on the serialization format of UDT and tuple values has been added to the documentation |
| (Section 7). |
| * The serialization format for collection has changed (both the collection size and |
| the length of each argument is now 4 bytes long). See Section 6. |
| * QUERY, EXECUTE and BATCH messages can now optionally provide the default timestamp for the query. |
| As this feature is optionally enabled by clients, implementing it is at the discretion of the |
| client. |
| * QUERY and EXECUTE messages can now optionally provide the names for the values of the |
| query. As this feature is optionally enabled by clients, implementing it is at the discretion of the |
| client (Note that while the BATCH message has a flag for this, it actually doesn't work for BATCH, |
| see Section 4.1.7 for details). |
| * The format of "Schema_change" results (Section 4.2.5.5) and "SCHEMA_CHANGE" events (Section 4.2.6) |
| has been modified, and now includes changes related to user types. |
| |