{"Entry":{"collection":"protocol","key":"cancelrequest-f","name":"CancelRequest","aliases":["CancelRequest","Int32(16)"],"metadata":{"aliases":["CancelRequest","Int32(16)"],"category":"Frontend messages","content_hash":"293452d7787c374c237a469e6b5543a8505b093f49eb7f0aeb61f41d3db843f5","derived_content_hash":"efff25f70deaa05702f14808ea6552f2c63e9a4ac195676fcdcdd83b8718fe39","imported_at":"2026-09-30T00:40:44.526912+08:00","name":"CancelRequest","name_zh":"","slug":"cancelrequest-f","summary":"CancelRequest is a frontend protocol message. Length of message contents in bytes, including self."}},"Definition":{"Collection":"protocol","Key":"cancelrequest-f","SourceDatabase":"center","Version":"18","SourceTable":"protocol_message","SourceKey":"cancelrequest-f","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","Facts":{"comparison_data":{"direction":"F","fields":[{"description":"Length of message contents in bytes, including self.","format":"Int32"},{"description":"The cancel request code. The value is chosen to contain 1234 in the most significant 16 bits, and 5678 in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)","format":"Int32(80877102)"},{"description":"The process ID of the target backend.","format":"Int32"},{"description":"The secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes.","format":"Byte n"}]},"comparison_hash":"dc899195882d7563007c3329b648b9516242e55a3833c0945e59840954fa37a8","description":["CancelRequest is a frontend protocol message. Length of message contents in bytes, including self."],"description_zh":"Int32 消息内容的长度（以字节为单位），包括其自身。 Int32(80877102) 取消请求代码。此值的最高 16 位为 1234 ，最低 16 位为 5678 。（为避免混淆，此代码不能与任何协议版本号相同。） Int32 目标后端的进程 ID。 Byte n 目标后端的密钥。此字段延伸至消息末尾，其范围由长度字段确定。密钥最长为 256 字节。 在协议版本 3.2 之前，密钥始终为 4 字节长。","description_zh_html":"\u003cp\u003e协议消息 CancelRequest (F)。\u003c/p\u003e\u003ch3\u003e同版本中文手册定义\u003c/h3\u003e\u003cdd\u003e\u003cdiv class=\"variablelist\"\u003e\u003cdl class=\"variablelist\"\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         消息内容的长度（以字节为单位），包括其自身。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32(80877102)\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         取消请求代码。此值的最高 16 位为 \u003ccode class=\"literal\"\u003e1234\u003c/code\u003e，最低 16 位为 \u003ccode class=\"literal\"\u003e5678\u003c/code\u003e。（为避免混淆，此代码不能与任何协议版本号相同。）\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         目标后端的进程 ID。\n        \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003eByte\u003cem class=\"replaceable\"\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e \u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n         目标后端的密钥。此字段延伸至消息末尾，其范围由长度字段确定。密钥最长为 256 字节。\n        \u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e\u003cp\u003e\n         在协议版本 3.2 之前，密钥始终为 4 字节长。\n        \u003c/p\u003e\u003c/dd\u003e\u003cp\u003e\u003ca href=\"/zh/docs/18/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-CANCELREQUEST\"\u003e查看完整中文手册与上下文\u003c/a\u003e。\u003c/p\u003e","direction":"F","facts":[{"label":"Direction","value":"Frontend → backend"},{"label":"First wire field","value":"Int32"},{"label":"Field entries","value":"4"},{"label":"Documented flow contexts","value":"Canceling Requests in Progress; SSL Session Encryption; GSSAPI Session Encryption"}],"facts_zh":[{"label":"方向","value":"前端 → 后端"},{"label":"首个线上协议字段","value":"Int32"},{"label":"字段条目","value":"4"},{"label":"手册中的交互阶段","value":"取消正在执行的请求；SSL 会话加密；GSSAPI 会话加密"}],"fields":[{"description":"Length of message contents in bytes, including self.","format":"Int32"},{"description":"The cancel request code. The value is chosen to contain 1234 in the most significant 16 bits, and 5678 in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)","format":"Int32(80877102)"},{"description":"The process ID of the target backend.","format":"Int32"},{"description":"The secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes.","format":"Byte n"}],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of message contents in bytes, including self.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32(80877102)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe cancel request code. The value is chosen to contain \u003ccode class=\"literal\"\u003e1234\u003c/code\u003e in the most significant 16 bits, and \u003ccode class=\"literal\"\u003e5678\u003c/code\u003e in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe process ID of the target backend.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte\u003cem class=\"replaceable\"\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eBefore protocol version 3.2, the secret key was always 4 bytes long.\u003c/p\u003e\n\u003c/dd\u003e\u003c/dl\u003e","manual_path":"/docs/18/protocol-message-formats.html","related":[{"label":"Protocol flow and exchange examples","url":"/docs/18/protocol-flow.html"},{"label":"Protocol overview","url":"/docs/18/protocol-overview.html"},{"label":"Canceling Requests in Progress","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-CANCELING-REQUESTS"},{"label":"SSL Session Encryption","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-SSL"},{"label":"GSSAPI Session Encryption","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-GSSAPI"}],"release":{"channel":"stable","label":"18.6","major":"18","ref":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2","revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"},"sections":[{"paragraphs":["The complete definition below retains repetition, counts and conditional fields. A numbered table row is a documented field definition, not a fixed byte offset. Integer encodings and flow rules follow the same-version protocol chapter."],"title":"Framing and repetition"}],"sections_zh":[{"paragraphs":["下方完整定义保留重复项、计数与条件字段。表格行号表示文档中的字段定义，并非固定字节偏移量。整数编码与交互流程以同版本协议章节为准。"],"title":"消息边界与重复字段"}],"signature":"CancelRequest (F)","sources":[{"label":"PostgreSQL 18 English manual","path":"protocol-message-formats.html","sha256":"53f37652ac2c089e30ada87d8aee7bdd0f26695b03f275302e526a807d2a1f23","url":"/docs/18/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-CANCELREQUEST"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Int32","c2":"Length of message contents in bytes, including self."},{"c0":"2","c1":"Int32(80877102)","c2":"The cancel request code. The value is chosen to contain 1234 in the most significant 16 bits, and 5678 in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)"},{"c0":"3","c1":"Int32","c2":"The process ID of the target backend."},{"c0":"4","c1":"Byte n","c2":"The secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes."}],"title":"Wire fields in documented order"}],"tables_zh":[{"columns":[{"key":"c0","label":"位置"},{"key":"c1","label":"格式"},{"key":"c2","label":"含义"}],"key":"fields","rows":[{"c0":"1","c1":"Int32","c2":"消息内容的长度（以字节为单位），包括其自身。"},{"c0":"2","c1":"Int32(80877102)","c2":"取消请求代码。其最高 16 位为 1234，最低 16 位为 5678。为避免混淆，此代码不得与任何协议版本号相同。"},{"c0":"3","c1":"Int32","c2":"目标后端的进程 ID。"},{"c0":"4","c1":"Byte n","c2":"目标后端的密钥。此字段延伸至消息末尾，其范围由长度字段确定。密钥最长为 256 字节。"}],"title":"按手册顺序排列的线上协议字段"}],"zh_from":{"authored_translation":"source-derived-identity","body_sha256":"9dbe48d30d7ff0e742b70f8d38bf92a2658fac2f65bf659f8a5aab3a3a507e45","kind":"same-version-chinese-manual-with-source-derived-identity","manual":{"anchor":"PROTOCOL-MESSAGE-FORMATS-CANCELREQUEST","build_id":107,"extraction":"exact-definition","fragment_sha256":"c1e11c902bdc934566a21878b581457cb51d5268eae565d54bf8309d76756daf","locale":"zh-Hans","page_key":"protocol-message-formats.html","source_hash":"0be0a37b38d80c96c157ca9fcfe9222995654664aad8136f7ac2b1b552f6753a","source_revision":"unknown:rendered-translation-baseline","translated_from_revision":null,"translation_revision":"git:b1b500221dbe5437cfca004d6b04d3f6e422765d;html-sha256:08e987a66af27b98444a8057c256314eafa13611a3fb9e888214fc436824244b","url":"/zh/docs/18/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-CANCELREQUEST","version":"18"},"runtime_rerun":false,"source_facts_revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}},"ManualEvidence":{"manual_path":"/docs/18/protocol-message-formats.html","release":{"channel":"stable","label":"18.6","major":"18","ref":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2","revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"},"sources":[{"label":"PostgreSQL 18 English manual","path":"protocol-message-formats.html","sha256":"53f37652ac2c089e30ada87d8aee7bdd0f26695b03f275302e526a807d2a1f23","url":"/docs/18/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-CANCELREQUEST"}]},"MeasuredEvidence":{}},"Text":{"Collection":"protocol","Key":"cancelrequest-f","SourceDatabase":"center","Version":"18","Locale":"en","Title":"CancelRequest","Summary":"CancelRequest is a frontend protocol message. Length of message contents in bytes, including self.","BodyHTML":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of message contents in bytes, including self.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32(80877102)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe cancel request code. The value is chosen to contain \u003ccode\u003e1234\u003c/code\u003e in the most significant 16 bits, and \u003ccode\u003e5678\u003c/code\u003e in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe process ID of the target backend.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eByte\u003cem\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eBefore protocol version 3.2, the secret key was always 4 bytes long.\u003c/p\u003e\n\u003c/dd\u003e\u003c/dl\u003e","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","ContentHash":"ac63a58de9eddbf1558d4baf853f72161cfc5ce2e4163cfa93bd45196d8ec7d6","Payload":{"description":["CancelRequest is a frontend protocol message. Length of message contents in bytes, including self."],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of message contents in bytes, including self.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32(80877102)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe cancel request code. The value is chosen to contain \u003ccode class=\"literal\"\u003e1234\u003c/code\u003e in the most significant 16 bits, and \u003ccode class=\"literal\"\u003e5678\u003c/code\u003e in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe process ID of the target backend.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte\u003cem class=\"replaceable\"\u003e\u003ccode\u003en\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eBefore protocol version 3.2, the secret key was always 4 bytes long.\u003c/p\u003e\n\u003c/dd\u003e\u003c/dl\u003e","related":[{"label":"Protocol flow and exchange examples","url":"/docs/18/protocol-flow.html"},{"label":"Protocol overview","url":"/docs/18/protocol-overview.html"},{"label":"Canceling Requests in Progress","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-CANCELING-REQUESTS"},{"label":"SSL Session Encryption","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-SSL"},{"label":"GSSAPI Session Encryption","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-GSSAPI"}],"sections":[{"paragraphs":["The complete definition below retains repetition, counts and conditional fields. A numbered table row is a documented field definition, not a fixed byte offset. Integer encodings and flow rules follow the same-version protocol chapter."],"title":"Framing and repetition"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Int32","c2":"Length of message contents in bytes, including self."},{"c0":"2","c1":"Int32(80877102)","c2":"The cancel request code. The value is chosen to contain 1234 in the most significant 16 bits, and 5678 in the least significant 16 bits. (To avoid confusion, this code must not be the same as any protocol version number.)"},{"c0":"3","c1":"Int32","c2":"The process ID of the target backend."},{"c0":"4","c1":"Byte n","c2":"The secret key for the target backend. This field extends to the end of the message, indicated by the length field. The maximum key length is 256 bytes."}],"title":"Wire fields in documented order"}]}},"RequestedLocale":"en","Fallback":false,"Versions":["10","11","12","13","14","15","16","17","18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}