PostgreSQL中PortalRunMulti函数和PortalRun函数的实现逻辑是什么-编程学习网

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一、基础信息

PortalRunMulti函数使用的数据结构、宏定义以及依赖的函数等。
数据结构/宏定义
1、Portal

 typedef struct PortalData *Portal;
 
 typedef struct PortalData
 {
     
     const char *name;           
     const char *prepStmtName;   
     MemoryContext portalContext;    
     ResourceOwner resowner;     
     void        (*cleanup) (Portal portal); 
 
     
     SubTransactionId createSubid;   
     SubTransactionId activeSubid;   
 
     
     const char *sourceText;     
     const char *commandTag;     
     List       *stmts;          
     CachedPlan *cplan;          
 
     ParamListInfo portalParams; 
     QueryEnvironment *queryEnv; 
 
     
     PortalStrategy strategy;    
     int         cursorOptions;  
     bool        run_once;       
 
     
     PortalStatus status;        
     bool        portalPinned;   
     bool        autoHeld;       
 
     
     QueryDesc  *queryDesc;      
 
     
     TupleDesc   tupDesc;        
     
     int16      *formats;        
 
     
     Tuplestorestate *holdStore; 
     MemoryContext holdContext;  
 
     
     Snapshot    holdSnapshot;   
 
     
     bool        atStart;
     bool        atEnd;
     uint64      portalPos;
 
     
     TimestampTz creation_time;  
     bool        visible;        
 }           PortalData;

2、List

 typedef struct ListCell ListCell;
 
 typedef struct List
 {
     NodeTag     type;           
     int         length;
     ListCell   *head;
     ListCell   *tail;
 } List;
 
 struct ListCell
 {
     union
     {
         void       *ptr_value;
         int         int_value;
         Oid         oid_value;
     }           data;
     ListCell   *next;
 };

3、Snapshot

typedef struct SnapshotData *Snapshot;
 
 typedef struct SnapshotData
 {
     SnapshotSatisfiesFunc satisfies;    
 
     
     TransactionId xmin;         
     TransactionId xmax;         
 
     
     TransactionId *xip;
     uint32      xcnt;           
 
     
     TransactionId *subxip;
     int32       subxcnt;        
     bool        suboverflowed;  
 
     bool        takenDuringRecovery;    
     bool        copied;         
 
     CommandId   curcid;         
 
     
     uint32      speculativeToken;
 
     
     uint32      active_count;   
     uint32      regd_count;     
     pairingheap_node ph_node;   
 
     TimestampTz whenTaken;      
     XLogRecPtr  lsn;            
 } SnapshotData;

依赖的函数
1、lfirst_*

 

 #define lnext(lc)               ((lc)->next)
 #define lfirst(lc)              ((lc)->data.ptr_value)
 #define lfirst_int(lc)          ((lc)->data.int_value)
 #define lfirst_oid(lc)          ((lc)->data.oid_value)
 #define lfirst_node(type,lc)    castNode(type, lfirst(lc))

 
 #ifdef USE_ASSERT_CHECKING
 static inline Node *
 castNodeImpl(NodeTag type, void *ptr)
 {
     Assert(ptr == NULL || nodeTag(ptr) == type);
     return (Node *) ptr;
 }
 #define castNode(_type_, nodeptr) ((_type_ *) castNodeImpl(T_##_type_, nodeptr))
 #else
 #define castNode(_type_, nodeptr) ((_type_ *) (nodeptr))
 #endif

2、Snapshot相关

//留待MVCC再行解读
GetTransactionSnapshot
RegisterSnapshot
PushCopiedSnapshot
UpdateActiveSnapshotCommandId
PopActiveSnapshot

3、ProcessQuery

//上一节已介绍

4、CommandCounterIncrement

 
 void
 CommandCounterIncrement(void)
 {
     
     if (currentCommandIdUsed)
     {
         
         if (IsInParallelMode() || IsParallelWorker())
             elog(ERROR, "cannot start commands during a parallel operation");
 
         currentCommandId += 1;
         if (currentCommandId == InvalidCommandId)
         {
             currentCommandId -= 1;
             ereport(ERROR,
                     (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                      errmsg("cannot have more than 2^32-2 commands in a transaction")));
         }
         currentCommandIdUsed = false;
 
         
         SnapshotSetCommandId(currentCommandId);
 
         
         AtCCI_LocalCache();
     }
 }

5、MemoryContextDeleteChildren

 
 void
 MemoryContextDeleteChildren(MemoryContext context)
 {
     AssertArg(MemoryContextIsValid(context));
 
     
     while (context->firstchild != NULL)
         MemoryContextDelete(context->firstchild);
 }

二、源码解读

1、PortalRun



bool
PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
          DestReceiver *dest, DestReceiver *altdest,
          char *completionTag)
{
    bool        result;//返回结果
    uint64      nprocessed;
    ResourceOwner saveTopTransactionResourceOwner;//高层事务资源宿主
    MemoryContext saveTopTransactionContext;//内存上下文
    Portal      saveActivePortal;//活动的Portal
    ResourceOwner saveResourceOwner;
    MemoryContext savePortalContext;
    MemoryContext saveMemoryContext;

    AssertArg(PortalIsValid(portal));

    TRACE_POSTGRESQL_QUERY_EXECUTE_START();

    
    if (completionTag)
        completionTag[0] = '\0';

    if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
    {
        elog(DEBUG3, "PortalRun");
        
        ResetUsage();
    }

    
    MarkPortalActive(portal);

    
    Assert(!portal->run_once || run_once);
    portal->run_once = run_once;

    
    //保护现场
    saveTopTransactionResourceOwner = TopTransactionResourceOwner;
    saveTopTransactionContext = TopTransactionContext;
    saveActivePortal = ActivePortal;
    saveResourceOwner = CurrentResourceOwner;
    savePortalContext = PortalContext;
    saveMemoryContext = CurrentMemoryContext;
    PG_TRY();
    {
        ActivePortal = portal;
        if (portal->resowner)
            CurrentResourceOwner = portal->resowner;
        PortalContext = portal->portalContext;

        MemoryContextSwitchTo(PortalContext);

        switch (portal->strategy)
        {
            case PORTAL_ONE_SELECT:
            case PORTAL_ONE_RETURNING:
            case PORTAL_ONE_MOD_WITH:
            case PORTAL_UTIL_SELECT:

                
                if (portal->strategy != PORTAL_ONE_SELECT && !portal->holdStore)
                    FillPortalStore(portal, isTopLevel);

                
                nprocessed = PortalRunSelect(portal, true, count, dest);

                
                if (completionTag && portal->commandTag)
                {
                    if (strcmp(portal->commandTag, "SELECT") == 0)
                        snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
                                 "SELECT " UINT64_FORMAT, nprocessed);
                    else
                        strcpy(completionTag, portal->commandTag);
                }

                
                portal->status = PORTAL_READY;

                
                result = portal->atEnd;
                break;

            case PORTAL_MULTI_QUERY://INSERT语句
                PortalRunMulti(portal, isTopLevel, false,
                               dest, altdest, completionTag);

                
                MarkPortalDone(portal);

                
                result = true;
                break;

            default:
                elog(ERROR, "unrecognized portal strategy: %d",
                     (int) portal->strategy);
                result = false; 
                break;
        }
    }
    PG_CATCH();
    {
        
        MarkPortalFailed(portal);

        
        if (saveMemoryContext == saveTopTransactionContext)
            MemoryContextSwitchTo(TopTransactionContext);
        else
            MemoryContextSwitchTo(saveMemoryContext);
        ActivePortal = saveActivePortal;
        if (saveResourceOwner == saveTopTransactionResourceOwner)
            CurrentResourceOwner = TopTransactionResourceOwner;
        else
            CurrentResourceOwner = saveResourceOwner;
        PortalContext = savePortalContext;

        PG_RE_THROW();
    }
    PG_END_TRY();

    if (saveMemoryContext == saveTopTransactionContext)
        MemoryContextSwitchTo(TopTransactionContext);
    else
        MemoryContextSwitchTo(saveMemoryContext);
    ActivePortal = saveActivePortal;
    if (saveResourceOwner == saveTopTransactionResourceOwner)
        CurrentResourceOwner = TopTransactionResourceOwner;
    else
        CurrentResourceOwner = saveResourceOwner;
    PortalContext = savePortalContext;

    if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
        ShowUsage("EXECUTOR STATISTICS");

    TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();

    return result;
}

2、PortalRunMulti



static void
PortalRunMulti(Portal portal,
               bool isTopLevel, bool setHoldSnapshot,
               DestReceiver *dest, DestReceiver *altdest,
               char *completionTag)
{
    bool        active_snapshot_set = false;//活跃snapshot？
    ListCell   *stmtlist_item;//SQL语句，临时变量

    
    if (dest->mydest == DestRemoteExecute)
        dest = None_Receiver;
    if (altdest->mydest == DestRemoteExecute)
        altdest = None_Receiver;

    
    foreach(stmtlist_item, portal->stmts)//循环处理SQL语句
    {
        PlannedStmt *pstmt = lfirst_node(PlannedStmt, stmtlist_item);//获取已规划的语句

        
        CHECK_FOR_INTERRUPTS();

        if (pstmt->utilityStmt == NULL)//非“工具类”语句
        {
            
            TRACE_POSTGRESQL_QUERY_EXECUTE_START();

            if (log_executor_stats)
                ResetUsage();

            
            if (!active_snapshot_set)
            {
                Snapshot    snapshot = GetTransactionSnapshot();//获取事务快照

                
                if (setHoldSnapshot)
                {
                    snapshot = RegisterSnapshot(snapshot);
                    portal->holdSnapshot = snapshot;
                }

                
                PushCopiedSnapshot(snapshot);
                active_snapshot_set = true;
            }
            else
                UpdateActiveSnapshotCommandId();

            //处理查询
            if (pstmt->canSetTag)
            {
                
                ProcessQuery(pstmt,
                             portal->sourceText,
                             portal->portalParams,
                             portal->queryEnv,
                             dest, completionTag);
            }
            else
            {
                
                ProcessQuery(pstmt,
                             portal->sourceText,
                             portal->portalParams,
                             portal->queryEnv,
                             altdest, NULL);
            }

            if (log_executor_stats)
                ShowUsage("EXECUTOR STATISTICS");

            TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();
        }
        else//“工具类”语句
        {
            
            if (pstmt->canSetTag)
            {
                Assert(!active_snapshot_set);
                
                PortalRunUtility(portal, pstmt, isTopLevel, false,
                                 dest, completionTag);
            }
            else
            {
                Assert(IsA(pstmt->utilityStmt, NotifyStmt));
                
                PortalRunUtility(portal, pstmt, isTopLevel, false,
                                 altdest, NULL);
            }
        }

        
        if (lnext(stmtlist_item) != NULL)
            CommandCounterIncrement();

        
        Assert(portal->portalContext == CurrentMemoryContext);

        MemoryContextDeleteChildren(portal->portalContext);//释放资源
    }

    
    if (active_snapshot_set)
        PopActiveSnapshot();

    
    if (completionTag && completionTag[0] == '\0')//操作提示
    {
        if (portal->commandTag)
            strcpy(completionTag, portal->commandTag);
        if (strcmp(completionTag, "SELECT") == 0)
            sprintf(completionTag, "SELECT 0 0");
        else if (strcmp(completionTag, "INSERT") == 0)
            strcpy(completionTag, "INSERT 0 0");
        else if (strcmp(completionTag, "UPDATE") == 0)
            strcpy(completionTag, "UPDATE 0");
        else if (strcmp(completionTag, "DELETE") == 0)
            strcpy(completionTag, "DELETE 0");
    }
}

三、跟踪分析

插入测试数据：

testdb=# -- 获取pid
testdb=# select pg_backend_pid();
 pg_backend_pid 
----------------
           2551
(1 row)
testdb=# -- 插入1行
testdb=# insert into t_insert values(20,'PortalRun','PortalRun','PortalRun');

启动gdb，跟踪调试：
1、PortalRun

[root@localhost ~]# gdb -p 2551
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-100.el7
Copyright (C) 2013 Free Software Foundation, Inc.
...
(gdb) b PortalRun
Breakpoint 1 at 0x8528af: file pquery.c, line 707.
(gdb) c
Continuing.

Breakpoint 1, PortalRun (portal=0x2c6f490, count=9223372036854775807, isTopLevel=true, run_once=true, dest=0x2ccb4d8, altdest=0x2ccb4d8, completionTag=0x7ffe94ba4940 "") at pquery.c:707
707     if (completionTag)
#查看输入参数
#1、portal
(gdb) p *portal
$1 = {name = 0x2c72e98 "", prepStmtName = 0x0, portalContext = 0x2cc1470, resowner = 0x2c3ad10, cleanup = 0x62f15c <PortalCleanup>, createSubid = 1, activeSubid = 1, 
  sourceText = 0x2c09ef0 "insert into t_insert values(20,'PortalRun','PortalRun','PortalRun');", commandTag = 0xb50908 "INSERT", stmts = 0x2ccb4a8, cplan = 0x0, portalParams = 0x0, queryEnv = 0x0, 
  strategy = PORTAL_MULTI_QUERY, cursorOptions = 4, run_once = false, status = PORTAL_READY, portalPinned = false, autoHeld = false, queryDesc = 0x0, tupDesc = 0x0, formats = 0x0, holdStore = 0x0, 
  holdContext = 0x0, holdSnapshot = 0x0, atStart = true, atEnd = true, portalPos = 0, creation_time = 587033564125509, visible = false}
(gdb) p *(portal->portalContext)
$2 = {type = T_AllocSetContext, isReset = true, allowInCritSection = false, methods = 0xb8c720 <AllocSetMethods>, parent = 0x2c6f380, firstchild = 0x0, prevchild = 0x0, nextchild = 0x0, 
  name = 0xb8d2f1 "PortalContext", ident = 0x2c72e98 "", reset_cbs = 0x0}
(gdb) p *(portal->resowner)
$3 = {parent = 0x2c35518, firstchild = 0x0, nextchild = 0x0, name = 0xb8d2ff "Portal", bufferarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, catrefarr = {
    itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, catlistrefarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, 
  relrefarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, planrefarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, 
  tupdescarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, snapshotarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, 
    lastidx = 0}, filearr = {itemsarr = 0x0, invalidval = 18446744073709551615, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, dsmarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, 
    nitems = 0, maxitems = 0, lastidx = 0}, jitarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, nlocks = 0, locks = {0x0 <repeats 15 times>}}
(gdb) p *(portal->resowner->parent)
$4 = {parent = 0x0, firstchild = 0x2c3ad10, nextchild = 0x0, name = 0xa1b515 "TopTransaction", bufferarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, 
  catrefarr = {itemsarr = 0x2c3b040, invalidval = 0, capacity = 16, nitems = 0, maxitems = 16, lastidx = 4294967295}, catlistrefarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, 
    maxitems = 0, lastidx = 0}, relrefarr = {itemsarr = 0x2c35728, invalidval = 0, capacity = 16, nitems = 0, maxitems = 16, lastidx = 4294967295}, planrefarr = {itemsarr = 0x0, invalidval = 0, 
    capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, tupdescarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, snapshotarr = {itemsarr = 0x0, 
    invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, filearr = {itemsarr = 0x0, invalidval = 18446744073709551615, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, dsmarr = {
    itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, jitarr = {itemsarr = 0x0, invalidval = 0, capacity = 0, nitems = 0, maxitems = 0, lastidx = 0}, nlocks = 1, 
  locks = {0x2c28320, 0x0 <repeats 14 times>}}
#2、count
(gdb) p count
$5 = 9223372036854775807
#3、isTopLevel
(gdb) p isTopLevel
$6 = true
#4、run_once
(gdb) p run_once
$7 = true
#5、dest
$8 = (DestReceiver *) 0x2ccb4d8
(gdb) p *dest
$9 = {receiveSlot = 0x4857ad <printtup>, rStartup = 0x485196 <printtup_startup>, rShutdown = 0x485bad <printtup_shutdown>, rDestroy = 0x485c21 <printtup_destroy>, mydest = DestRemote}
(gdb) 
#6、altdest
(gdb) p altdest
$10 = (DestReceiver *) 0x2ccb4d8
(gdb) p *altdest
$11 = {receiveSlot = 0x4857ad <printtup>, rStartup = 0x485196 <printtup_startup>, rShutdown = 0x485bad <printtup_shutdown>, rDestroy = 0x485c21 <printtup_destroy>, mydest = DestRemote}
(gdb) 
#7、completionTag
(gdb) p completionTag
$12 = 0x7ffe94ba4940 ""
#单步调试
710     if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
(gdb) 
720     MarkPortalActive(portal);
(gdb) 
724     portal->run_once = run_once;
(gdb) 
740     saveTopTransactionResourceOwner = TopTransactionResourceOwner;
(gdb) 
741     saveTopTransactionContext = TopTransactionContext;
(gdb) 
742     saveActivePortal = ActivePortal;
(gdb) 
743     saveResourceOwner = CurrentResourceOwner;
(gdb) 
744     savePortalContext = PortalContext;
(gdb) 
745     saveMemoryContext = CurrentMemoryContext;
(gdb) 
746     PG_TRY();
(gdb) 
748         ActivePortal = portal;
(gdb) 
749         if (portal->resowner)
(gdb) 
750             CurrentResourceOwner = portal->resowner;
(gdb) 
751         PortalContext = portal->portalContext;
(gdb) 
753         MemoryContextSwitchTo(PortalContext);
(gdb) 
755         switch (portal->strategy)
(gdb) p portal->strategy
$13 = PORTAL_MULTI_QUERY
(gdb) next
799                 PortalRunMulti(portal, isTopLevel, false,
(gdb) 
803                 MarkPortalDone(portal);
(gdb) 
806                 result = true;
(gdb) 
807                 break;
(gdb) 
835     PG_END_TRY();
(gdb) 
837     if (saveMemoryContext == saveTopTransactionContext)
(gdb) 
838         MemoryContextSwitchTo(TopTransactionContext);
(gdb) 
841     ActivePortal = saveActivePortal;
(gdb) 
842     if (saveResourceOwner == saveTopTransactionResourceOwner)
(gdb) 
843         CurrentResourceOwner = TopTransactionResourceOwner;
(gdb) 
846     PortalContext = savePortalContext;
(gdb) 
848     if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
(gdb) 
853     return result;
(gdb) 
854 }
#DONE!

2、PortalRunMulti

(gdb) b PortalRunMulti
Breakpoint 1 at 0x8533df: file pquery.c, line 1210.
(gdb) c
Continuing.

Breakpoint 1, PortalRunMulti (portal=0x2c6f490, isTopLevel=true, setHoldSnapshot=false, dest=0x2cbe8f8, altdest=0x2cbe8f8, completionTag=0x7ffe94ba4940 "") at pquery.c:1210
1210        bool        active_snapshot_set = false;
#输入参数
#1、portal
(gdb) p *portal
$1 = {name = 0x2c72e98 "", prepStmtName = 0x0, portalContext = 0x2c2d3d0, resowner = 0x2c3ad10, cleanup = 0x62f15c <PortalCleanup>, createSubid = 1, activeSubid = 1, 
  sourceText = 0x2c09ef0 "insert into t_insert values(21,'PortalRunMulti','PortalRunMulti','PortalRunMulti');", commandTag = 0xb50908 "INSERT", stmts = 0x2cbe8c8, cplan = 0x0, portalParams = 0x0, 
  queryEnv = 0x0, strategy = PORTAL_MULTI_QUERY, cursorOptions = 4, run_once = true, status = PORTAL_ACTIVE, portalPinned = false, autoHeld = false, queryDesc = 0x0, tupDesc = 0x0, formats = 0x0, 
  holdStore = 0x0, holdContext = 0x0, holdSnapshot = 0x0, atStart = true, atEnd = true, portalPos = 0, creation_time = 587034112962796, visible = false}
(gdb) p *(portal->portalContext)
$2 = {type = T_AllocSetContext, isReset = true, allowInCritSection = false, methods = 0xb8c720 <AllocSetMethods>, parent = 0x2c6f380, firstchild = 0x0, prevchild = 0x0, nextchild = 0x0, 
  name = 0xb8d2f1 "PortalContext", ident = 0x2c72e98 "", reset_cbs = 0x0}
#2、isTopLevel
(gdb) p isTopLevel
$3 = true
#3、setHoldSnapshot
(gdb) p setHoldSnapshot
$4 = false
#4、dest
(gdb) p *dest
$5 = {receiveSlot = 0x4857ad <printtup>, rStartup = 0x485196 <printtup_startup>, rShutdown = 0x485bad <printtup_shutdown>, rDestroy = 0x485c21 <printtup_destroy>, mydest = DestRemote}
#5、altdest
(gdb) p *altdest
$6 = {receiveSlot = 0x4857ad <printtup>, rStartup = 0x485196 <printtup_startup>, rShutdown = 0x485bad <printtup_shutdown>, rDestroy = 0x485c21 <printtup_destroy>, mydest = DestRemote}
#6、completionTag
(gdb) p *completionTag
$7 = 0 '\000'
#单步调试
...
(gdb) next
1234            PlannedStmt *pstmt = lfirst_node(PlannedStmt, stmtlist_item);
(gdb) 
1239            CHECK_FOR_INTERRUPTS();
(gdb) p *pstmt
$12 = {type = T_PlannedStmt, commandType = CMD_INSERT, queryId = 0, hasReturning = false, hasModifyingCTE = false, canSetTag = true, transientPlan = false, dependsOnRole = false, 
  parallelModeNeeded = false, jitFlags = 0, planTree = 0x2c0aff8, rtable = 0x2cbe7d8, resultRelations = 0x2cbe878, nonleafResultRelations = 0x0, rootResultRelations = 0x0, subplans = 0x0, 
  rewindPlanIDs = 0x0, rowMarks = 0x0, relationOids = 0x2cbe828, invalItems = 0x0, paramExecTypes = 0x2c31700, utilityStmt = 0x0, stmt_location = 0, stmt_len = 82}
(gdb) next
1241            if (pstmt->utilityStmt == NULL)
(gdb) 
1248                if (log_executor_stats)
(gdb) 
1257                if (!active_snapshot_set)
(gdb) 
1259                    Snapshot    snapshot = GetTransactionSnapshot();
(gdb) 
1262                    if (setHoldSnapshot)
(gdb) p *snapshot
$13 = {satisfies = 0x9f73fc <HeapTupleSatisfiesMVCC>, xmin = 1612887, xmax = 1612887, xip = 0x2c2d1c0, xcnt = 0, subxip = 0x2c81c70, subxcnt = 0, suboverflowed = false, takenDuringRecovery = false, 
  copied = false, curcid = 0, speculativeToken = 0, active_count = 0, regd_count = 0, ph_node = {first_child = 0x0, next_sibling = 0x0, prev_or_parent = 0x0}, whenTaken = 0, lsn = 0}
(gdb) 
...
(gdb) 
PortalRun (portal=0x2c6f490, count=9223372036854775807, isTopLevel=true, run_once=true, dest=0x2cbe8f8, altdest=0x2cbe8f8, completionTag=0x7ffe94ba4940 "INSERT 0 1") at pquery.c:803
803                 MarkPortalDone(portal);
#DONE!

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PostgreSQL中PortalRunMulti函数和PortalRun函数的实现逻辑是什么

一、基础信息

二、源码解读

三、跟踪分析

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