MainLoop.c （4）结构体PGconn 和 PGresult

MainLoop.c 文件中重要的结构体

/*
 * Global psql options
 */

PsqlSettings pset 中的PGconn

/* * PGconn stores all the state data associated with a single connection * to a backend. */struct pg_conn{/* Saved values of connection options */char   *pghost;//服务器主机名称char   *pghostaddr;//服务器主机IPV4地址char   *pgport;//与服务器通讯端口char   *pgunixsocket;/* the Unix-domain socket that the server is * listening on; if NULL, uses a default * constructed from pgport */char   *pgtty;/* tty on which the backend messages is * displayed (OBSOLETE, NOT USED) */char   *connect_timeout;//超时时间char   *client_encoding_initial;/* encoding to use */char   *pgoptions;/* options to start the backend with */char   *appname;/* application name */char   *fbappname;/* fallback application name */char   *dbName;/* database name */char   *replication;/* connect as the replication standby? */char   *pguser;/* Postgres username and password, if any */char   *pgpass;char   *keepalives;/* use TCP keepalives? */char   *keepalives_idle;/* time between TCP keepalives */char   *keepalives_interval;/* time between TCP keepalive * retransmits */char   *keepalives_count;/* maximum number of TCP keepalive * retransmits */char   *sslmode;/* SSL mode (require,prefer,allow,disable) */char   *sslkey;/* client key filename */char   *sslcert;/* client certificate filename */char   *sslrootcert;/* root certificate filename */char   *sslcrl;/* certificate revocation list filename */char   *requirepeer;/* required peer credentials for local sockets */#if defined(KRB5) || defined(ENABLE_GSS) || defined(ENABLE_SSPI)char   *krbsrvname;/* Kerberos service name */#endif/* Optional file to write trace info to */FILE   *Pfdebug;/* Callback procedures for notice message processing */PGNoticeHooks noticeHooks;/* Event procs registered via PQregisterEventProc */PGEvent    *events;/* expandable array of event data */intnEvents;/* number of active events */inteventArraySize; /* allocated array size *//* Status indicators */ConnStatusType status;PGAsyncStatusType asyncStatus;PGTransactionStatusType xactStatus; /* never changes to ACTIVE */PGQueryClass queryclass;char   *last_query;/* last SQL command, or NULL if unknown */charlast_sqlstate[6];/* last reported SQLSTATE */booloptions_valid;/* true if OK to attempt connection */boolnonblocking;/* whether this connection is using nonblock * sending semantics */charcopy_is_binary; /* 1 = copy binary, 0 = copy text */intcopy_already_done;/* # bytes already returned in COPY * OUT */PGnotify   *notifyHead;/* oldest unreported Notify msg */PGnotify   *notifyTail;/* newest unreported Notify msg *//* Connection data */intsock;/* Unix FD for socket, -1 if not connected */SockAddrladdr;/* Local address */SockAddrraddr;/* Remote address */ProtocolVersion pversion;/* FE/BE protocol version in use */intsversion;/* server version, e.g. 70401 for 7.4.1 */boolauth_req_received;/* true if any type of auth req * received */boolpassword_needed;/* true if server demanded a password */booldot_pgpass_used;/* true if used .pgpass */boolsigpipe_so;/* have we masked SIGPIPE via SO_NOSIGPIPE? */boolsigpipe_flag;/* can we mask SIGPIPE via MSG_NOSIGNAL? *//* Transient state needed while establishing connection */struct addrinfo *addrlist;/* list of possible backend addresses */struct addrinfo *addr_cur;/* the one currently being tried */intaddrlist_family;/* needed to know how to free addrlist */PGSetenvStatusType setenv_state;/* for 2.0 protocol only */const PQEnvironmentOption *next_eo;boolsend_appname;/* okay to send application_name? *//* Miscellaneous stuff */intbe_pid;/* PID of backend --- needed for cancels */intbe_key;/* key of backend --- needed for cancels */charmd5Salt[4];/* password salt received from backend */pgParameterStatus *pstatus; /* ParameterStatus data */intclient_encoding;/* encoding id */boolstd_strings;/* standard_conforming_strings */PGVerbosity verbosity;/* error/notice message verbosity */PGlobjfuncs *lobjfuncs;/* private state for large-object access fns *//* Buffer for data received from backend and not yet processed */char   *inBuffer;/* currently allocated buffer */intinBufSize;/* allocated size of buffer */intinStart;/* offset to first unconsumed data in buffer */intinCursor;/* next byte to tentatively consume */intinEnd;/* offset to first position after avail data *//* Buffer for data not yet sent to backend */char   *outBuffer;/* currently allocated buffer */intoutBufSize;/* allocated size of buffer */intoutCount;/* number of chars waiting in buffer *//* State for constructing messages in outBuffer */intoutMsgStart;/* offset to msg start (length word); if -1, * msg has no length word */intoutMsgEnd;/* offset to msg end (so far) *//* Status for asynchronous result construction */PGresult   *result;/* result being constructed */PGresAttValue *curTuple;/* tuple currently being read */#ifdef USE_SSLboolallow_ssl_try;/* Allowed to try SSL negotiation */boolwait_ssl_try;/* Delay SSL negotiation until after * attempting normal connection */SSL   *ssl;/* SSL status, if have SSL connection */X509   *peer;/* X509 cert of server */#ifdef USE_SSL_ENGINEENGINE   *engine;/* SSL engine, if any */#elsevoid   *engine;/* dummy field to keep struct the same if * OpenSSL version changes */#endif#endif   /* USE_SSL */#ifdef ENABLE_GSSgss_ctx_id_t gctx;/* GSS context */gss_name_tgtarg_nam;/* GSS target name */gss_buffer_desc ginbuf;/* GSS input token */gss_buffer_desc goutbuf;/* GSS output token */#endif#ifdef ENABLE_SSPI#ifndef ENABLE_GSSgss_buffer_desc ginbuf;/* GSS input token */#elsechar   *gsslib;/* What GSS librart to use ("gssapi" or * "sspi") */#endifCredHandle *sspicred;/* SSPI credentials handle */CtxtHandle *sspictx;/* SSPI context */char   *sspitarget;/* SSPI target name */intusesspi;/* Indicate if SSPI is in use on the * connection */#endif/* Buffer for current error message */PQExpBufferData errorMessage;//错误信息缓存/* Buffer for receiving various parts of messages */PQExpBufferData workBuffer; //工作缓存};

SendQuery函数中的PGresult   *results 

struct pg_result{intntups;intnumAttributes;PGresAttDesc *attDescs;PGresAttValue **tuples;/* each PGresTuple is an array of * PGresAttValue's */inttupArrSize;/* allocated size of tuples array */intnumParameters;PGresParamDesc *paramDescs;ExecStatusType resultStatus;charcmdStatus[CMDSTATUS_LEN];/* cmd status from the query */intbinary;/* binary tuple values if binary == 1, * otherwise text *//* * These fields are copied from the originating PGconn, so that operations * on the PGresult don't have to reference the PGconn. */PGNoticeHooks noticeHooks;PGEvent    *events;intnEvents;intclient_encoding;/* encoding id *//* * Error information (all NULL if not an error result).  errMsg is the * "overall" error message returned by PQresultErrorMessage.  If we have * per-field info then it is stored in a linked list. */char   *errMsg;/* error message, or NULL if no error */PGMessageField *errFields;/* message broken into fields *//* All NULL attributes in the query result point to this null string */charnull_field[1];/* * Space management information.  Note that attDescs and error stuff, if * not null, point into allocated blocks.  But tuples points to a * separately malloc'd block, so that we can realloc it. */PGresult_data *curBlock;/* most recently allocated block */intcurOffset;/* start offset of free space in block */intspaceLeft;/* number of free bytes remaining in block */};