更详细的描述，可参考手册：
http://58.58.27.50:8079/doc/html/9.3.1_zh/protocol-flow.html#AEN98678
下面是服务端处理简单查询和扩展查询的代码概要
1.简单查询
点击(此处)折叠或打开
bind消息的处理：
GetCachedPlan()会决定新创建一个定制的执行计划还是使用之前保存的通用的执行计划。
execute消息的处理：
close消息的处理：
http://blog.chinaunix.net/xmlrpc.php?r=blog/article&uid=20726500&id=4150218
src/backend/tcop/postgres.c
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exec_simple_query(const char *query_string)
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->parsetree_list = pg_parse_query(query_string);
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->foreach(parsetree_item, parsetree_list)
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->querytree_list = pg_analyze_and_rewrite(parsetree, query_string,NULL, 0);
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->plantree_list = pg_plan_queries(querytree_list, 0, NULL);
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->portal = CreatePortal("", true, true);
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->PortalDefineQuery(portal,NULL,query_string,commandTag,plantree_list,NULL);
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->PortalStart(portal, NULL, 0, InvalidSnapshot);
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->PortalRun(portal,FETCH_ALL,isTopLevel,receiver,receiver,completionTag);
- ->PortalDrop(portal, false);
2.扩展查询
parse消息的处理（命名语句）：点击(此处)折叠或打开
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exec_parse_message(const char *query_string,const char *stmt_name,Oid *paramTypes,int numParams)
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->parsetree_list = pg_parse_query(query_string);
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->raw_parse_tree = (Node *) linitial(parsetree_list);
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->psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag);
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->query = parse_analyze_varparams(raw_parse_tree,query_string,¶mTypes,&numParams);
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->querytree_list = pg_rewrite_query(query);
- ->CompleteCachedPlan(psrc,querytree_list,unnamed_stmt_context,paramTypes,numParams,NULL,NULL,0,true);
- ->StorePreparedStatement(stmt_name, psrc, false);
bind消息的处理：
点击(此处)折叠或打开
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exec_bind_message(StringInfo input_message)
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->portal_name = pq_getmsgstring(input_message);
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->stmt_name = pq_getmsgstring(input_message);
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->pstmt = FetchPreparedStatement(stmt_name, true);
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->psrc = pstmt->plansource;
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->cplan = GetCachedPlan(psrc, params, false);
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->portal = CreatePortal(portal_name, true, true);
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->PortalDefineQuery(portal,saved_stmt_name,query_string,psrc->commandTag,cplan->stmt_list,cplan);
- ->PortalStart(portal, params, 0, InvalidSnapshot);
execute消息的处理：
点击(此处)折叠或打开
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exec_execute_message(const char *portal_name, long max_rows)
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->portal = GetPortalByName(portal_name);
- ->completed = PortalRun(portal,max_rows,true,receiver,receiver,completionTag);
close消息的处理：
点击(此处)折叠或打开
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PostgresMain(int argc, char *argv[],const char *dbname,const char *username)
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case 'C':
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->DropPreparedStatement(close_target, false);
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or
- ->PortalDrop(portal, false);
3.参考
http://58.58.27.50:8079/doc/html/9.3.1_zh/protocol-flow.html#AEN98678http://blog.chinaunix.net/xmlrpc.php?r=blog/article&uid=20726500&id=4150218
src/backend/tcop/postgres.c