这篇文章主要介绍“PostgreSQL中什么函数通过递归调用初始化计划树中的所有Plan节点”，在日常操作中，相信很多人在PostgreSQL中什么函数通过递归调用初始化计划树中的所有Plan节点问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”PostgreSQL中什么函数通过递归调用初始化计划树中的所有Plan节点”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
一、数据结构
Plan
所有计划节点通过将Plan结构作为第一个字段从Plan结构“派生”。这确保了在将节点转换为计划节点时，一切都能正常工作。(在执行器中以通用方式传递时，节点指针经常被转换为Plan *)
typedef struct Plan
{
NodeTag type;//节点类型
Cost startup_cost;
Cost total_cost;
double plan_rows;
int plan_width;
bool parallel_aware;
bool parallel_safe;
int plan_node_id;
List *targetlist;
List *qual;
struct Plan *lefttree;
struct Plan *righttree;
List *initPlan;
Bitmapset *extParam;
Bitmapset *allParam;
} Plan;二、源码解读
ExecInitNode函数递归初始化计划树中的所有Plan节点,返回对应给定的Plan Node节点的PlanState节点.
PlanState *
ExecInitNode(Plan *node, EState *estate, int eflags)
{
PlanState *result;//结果
List *subps;//子PlanState链表
ListCell *l;//临时变量
if (node == NULL)
return NULL;
check_stack_depth();
switch (nodeTag(node))//根据节点类型进入相应的逻辑
{
case T_Result:
result = (PlanState *) ExecInitResult((Result *) node,
estate, eflags);
break;
case T_ProjectSet:
result = (PlanState *) ExecInitProjectSet((ProjectSet *) node,
estate, eflags);
break;
case T_ModifyTable:
result = (PlanState *) ExecInitModifyTable((ModifyTable *) node,
estate, eflags);
break;
case T_Append:
result = (PlanState *) ExecInitAppend((Append *) node,
estate, eflags);
break;
case T_MergeAppend:
result = (PlanState *) ExecInitMergeAppend((MergeAppend *) node,
estate, eflags);
break;
case T_RecursiveUnion:
result = (PlanState *) ExecInitRecursiveUnion((RecursiveUnion *) node,
estate, eflags);
break;
case T_BitmapAnd:
result = (PlanState *) ExecInitBitmapAnd((BitmapAnd *) node,
estate, eflags);
break;
case T_BitmapOr:
result = (PlanState *) ExecInitBitmapOr((BitmapOr *) node,
estate, eflags);
break;
case T_SeqScan:
result = (PlanState *) ExecInitSeqScan((SeqScan *) node,
estate, eflags);
break;
case T_SampleScan:
result = (PlanState *) ExecInitSampleScan((SampleScan *) node,
estate, eflags);
break;
case T_IndexScan:
result = (PlanState *) ExecInitIndexScan((IndexScan *) node,
estate, eflags);
break;
case T_IndexOnlyScan:
result = (PlanState *) ExecInitIndexOnlyScan((IndexOnlyScan *) node,
estate, eflags);
break;
case T_BitmapIndexScan:
result = (PlanState *) ExecInitBitmapIndexScan((BitmapIndexScan *) node,
estate, eflags);
break;
case T_BitmapHeapScan:
result = (PlanState *) ExecInitBitmapHeapScan((BitmapHeapScan *) node,
estate, eflags);
break;
case T_TidScan:
result = (PlanState *) ExecInitTidScan((TidScan *) node,
estate, eflags);
break;
case T_SubqueryScan:
result = (PlanState *) ExecInitSubqueryScan((SubqueryScan *) node,
estate, eflags);
break;
case T_FunctionScan:
result = (PlanState *) ExecInitFunctionScan((FunctionScan *) node,
estate, eflags);
break;
case T_TableFuncScan:
result = (PlanState *) ExecInitTableFuncScan((TableFuncScan *) node,
estate, eflags);
break;
case T_ValuesScan:
result = (PlanState *) ExecInitValuesScan((ValuesScan *) node,
estate, eflags);
break;
case T_CteScan:
result = (PlanState *) ExecInitCteScan((CteScan *) node,
estate, eflags);
break;
case T_NamedTuplestoreScan:
result = (PlanState *) ExecInitNamedTuplestoreScan((NamedTuplestoreScan *) node,
estate, eflags);
break;
case T_WorkTableScan:
result = (PlanState *) ExecInitWorkTableScan((WorkTableScan *) node,
estate, eflags);
break;
case T_ForeignScan:
result = (PlanState *) ExecInitForeignScan((ForeignScan *) node,
estate, eflags);
break;
case T_CustomScan:
result = (PlanState *) ExecInitCustomScan((CustomScan *) node,
estate, eflags);
break;
case T_NestLoop:
result = (PlanState *) ExecInitNestLoop((NestLoop *) node,
estate, eflags);
break;
case T_MergeJoin:
result = (PlanState *) ExecInitMergeJoin((MergeJoin *) node,
estate, eflags);
break;
case T_HashJoin:
result = (PlanState *) ExecInitHashJoin((HashJoin *) node,
estate, eflags);
break;
case T_Material:
result = (PlanState *) ExecInitMaterial((Material *) node,
estate, eflags);
break;
case T_Sort:
result = (PlanState *) ExecInitSort((Sort *) node,
estate, eflags);
break;
case T_Group:
result = (PlanState *) ExecInitGroup((Group *) node,
estate, eflags);
break;
case T_Agg:
result = (PlanState *) ExecInitAgg((Agg *) node,
estate, eflags);
break;
case T_WindowAgg:
result = (PlanState *) ExecInitWindowAgg((WindowAgg *) node,
estate, eflags);
break;
case T_Unique:
result = (PlanState *) ExecInitUnique((Unique *) node,
estate, eflags);
break;
case T_Gather:
result = (PlanState *) ExecInitGather((Gather *) node,
estate, eflags);
break;
case T_GatherMerge:
result = (PlanState *) ExecInitGatherMerge((GatherMerge *) node,
estate, eflags);
break;
case T_Hash:
result = (PlanState *) ExecInitHash((Hash *) node,
estate, eflags);
break;
case T_SetOp:
result = (PlanState *) ExecInitSetOp((SetOp *) node,
estate, eflags);
break;
case T_LockRows:
result = (PlanState *) ExecInitLockRows((LockRows *) node,
estate, eflags);
break;
case T_Limit:
result = (PlanState *) ExecInitLimit((Limit *) node,
estate, eflags);
break;
default:
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
result = NULL;
break;
}
//设置节点的ExecProcNode函数
ExecSetExecProcNode(result, result->ExecProcNode);
subps = NIL;//初始化
foreach(l, node->initPlan)//遍历initPlan
{
SubPlan *subplan = (SubPlan *) lfirst(l);//子计划
SubPlanState *sstate;//子计划状态
Assert(IsA(subplan, SubPlan));
sstate = ExecInitSubPlan(subplan, result);//初始化SubPlan
subps = lappend(subps, sstate);//添加到链表中
}
result->initPlan = subps;//赋值
//如需要,配置instrumentation
if (estate->es_instrument)
result->instrument = InstrAlloc(1, estate->es_instrument);
return result;
}
void
ExecSetExecProcNode(PlanState *node, ExecProcNodeMtd function)
{
node->ExecProcNodeReal = function;
node->ExecProcNode = ExecProcNodeFirst;
}
SeqScanState *
ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
{
SeqScanState *scanstate;
Assert(outerPlan(node) == NULL);
Assert(innerPlan(node) == NULL);
scanstate = makeNode(SeqScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecSeqScan;
ExecAssignExprContext(estate, &scanstate->ss.ps);
scanstate->ss.ss_currentRelation =
ExecOpenScanRelation(estate,
node->scanrelid,
eflags);
//使用合适的rowtype打开slot
ExecInitScanTupleSlot(estate, &scanstate->ss,
RelationGetDescr(scanstate->ss.ss_currentRelation));
ExecInitResultTypeTL(&scanstate->ss.ps);
ExecAssignScanProjectionInfo(&scanstate->ss);
scanstate->ss.ps.qual =
ExecInitQual(node->plan.qual, (PlanState *) scanstate);
return scanstate;
}
Relation
ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
{
Relation rel;
//打开关系
rel = ExecGetRangeTableRelation(estate, scanrelid);
if ((eflags & (EXEC_FLAG_EXPLAIN_ONLY | EXEC_FLAG_WITH_NO_DATA)) == 0 &&
!RelationIsScannable(rel))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("materialized view \"%s\" has not been populated",
RelationGetRelationName(rel)),
errhint("Use the REFRESH MATERIALIZED VIEW command.")));
return rel;
}
HashJoinState *
ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
{
HashJoinState *hjstate;
Plan *outerNode;
Hash *hashNode;
List *lclauses;
List *rclauses;
List *rhclauses;
List *hoperators;
TupleDesc outerDesc,
innerDesc;
ListCell *l;
//校验不支持的flags
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
hjstate = makeNode(HashJoinState);
hjstate->js.ps.plan = (Plan *) node;
hjstate->js.ps.state = estate;
hjstate->js.ps.ExecProcNode = ExecHashJoin;
hjstate->js.jointype = node->join.jointype;
ExecAssignExprContext(estate, &hjstate->js.ps);
outerNode = outerPlan(node);
hashNode = (Hash *) innerPlan(node);
outerPlanState(hjstate) = ExecInitNode(outerNode, estate, eflags);//递归处理外表节点
outerDesc = ExecGetResultType(outerPlanState(hjstate));//
innerPlanState(hjstate) = ExecInitNode((Plan *) hashNode, estate, eflags);//递归处理内表节点
innerDesc = ExecGetResultType(innerPlanState(hjstate));
ExecInitResultTupleSlotTL(&hjstate->js.ps);
ExecAssignProjectionInfo(&hjstate->js.ps, NULL);
hjstate->hj_OuterTupleSlot = ExecInitExtraTupleSlot(estate, outerDesc);
hjstate->js.single_match = (node->join.inner_unique ||
node->join.jointype == JOIN_SEMI);
//配置外连接的NULL元组
switch (node->join.jointype)
{
case JOIN_INNER:
case JOIN_SEMI:
break;
case JOIN_LEFT:
case JOIN_ANTI://左连接&半连接
hjstate->hj_NullInnerTupleSlot =
ExecInitNullTupleSlot(estate, innerDesc);
break;
case JOIN_RIGHT:
hjstate->hj_NullOuterTupleSlot =
ExecInitNullTupleSlot(estate, outerDesc);
break;
case JOIN_FULL:
hjstate->hj_NullOuterTupleSlot =
ExecInitNullTupleSlot(estate, outerDesc);
hjstate->hj_NullInnerTupleSlot =
ExecInitNullTupleSlot(estate, innerDesc);
break;
default:
elog(ERROR, "unrecognized join type: %d",
(int) node->join.jointype);
}
{
HashState *hashstate = (HashState *) innerPlanState(hjstate);
TupleTableSlot *slot = hashstate->ps.ps_ResultTupleSlot;
hjstate->hj_HashTupleSlot = slot;
}
hjstate->js.ps.qual =
ExecInitQual(node->join.plan.qual, (PlanState *) hjstate);
hjstate->js.joinqual =
ExecInitQual(node->join.joinqual, (PlanState *) hjstate);
hjstate->hashclauses =
ExecInitQual(node->hashclauses, (PlanState *) hjstate);
hjstate->hj_HashTable = NULL;
hjstate->hj_FirstOuterTupleSlot = NULL;
hjstate->hj_CurHashValue = 0;
hjstate->hj_CurBucketNo = 0;
hjstate->hj_CurSkewBucketNo = INVALID_SKEW_BUCKET_NO;
hjstate->hj_CurTuple = NULL;
lclauses = NIL;
rclauses = NIL;
rhclauses = NIL;
hoperators = NIL;
foreach(l, node->hashclauses)
{
OpExpr *hclause = lfirst_node(OpExpr, l);
lclauses = lappend(lclauses, ExecInitExpr(linitial(hclause->args),
(PlanState *) hjstate));
rclauses = lappend(rclauses, ExecInitExpr(lsecond(hclause->args),
(PlanState *) hjstate));
rhclauses = lappend(rhclauses, ExecInitExpr(lsecond(hclause->args),
innerPlanState(hjstate)));
hoperators = lappend_oid(hoperators, hclause->opno);
}
hjstate->hj_OuterHashKeys = lclauses;
hjstate->hj_InnerHashKeys = rclauses;
hjstate->hj_HashOperators = hoperators;
((HashState *) innerPlanState(hjstate))->hashkeys = rhclauses;
hjstate->hj_JoinState = HJ_BUILD_HASHTABLE;
hjstate->hj_MatchedOuter = false;
hjstate->hj_OuterNotEmpty = false;
return hjstate;
}三、跟踪分析
测试脚本如下
testdb=# explain select dw.*,grjf.grbh,grjf.xm,grjf.ny,grjf.je
testdb-# from t_dwxx dw,lateral (select gr.grbh,gr.xm,jf.ny,jf.je
testdb(# from t_grxx gr inner join t_jfxx jf
testdb(# on gr.dwbh = dw.dwbh
testdb(# and gr.grbh = jf.grbh) grjf
testdb-# order by dw.dwbh;
QUERY PLAN
------------------------------------------------------------------------------------------
Sort (cost=20070.93..20320.93 rows=100000 width=47)
Sort Key: dw.dwbh
-> Hash Join (cost=3754.00..8689.61 rows=100000 width=47)
Hash Cond: ((gr.dwbh)::text = (dw.dwbh)::text)
-> Hash Join (cost=3465.00..8138.00 rows=100000 width=31)
Hash Cond: ((jf.grbh)::text = (gr.grbh)::text)
-> Seq Scan on t_jfxx jf (cost=0.00..1637.00 rows=100000 width=20)
-> Hash (cost=1726.00..1726.00 rows=100000 width=16)
-> Seq Scan on t_grxx gr (cost=0.00..1726.00 rows=100000 width=16)
-> Hash (cost=164.00..164.00 rows=10000 width=20)
-> Seq Scan on t_dwxx dw (cost=0.00..164.00 rows=10000 width=20)
(11 rows)启动gdb,设置断点,进入ExecInitNode
(gdb) b ExecInitNode
Breakpoint 1 at 0x6e3b90: file execProcnode.c, line 148.
(gdb) c
Continuing.
Breakpoint 1, ExecInitNode (node=0x1b71f90, estate=0x1b78f48, eflags=16) at execProcnode.c:148
warning: Source file is more recent than executable.
148 if (node == NULL)输入参数,node为T_Sort
(gdb) p *node
$1 = {type = T_Sort, startup_cost = 20070.931487218411, total_cost = 20320.931487218411, plan_rows = 100000,
plan_width = 47, parallel_aware = false, parallel_safe = true, plan_node_id = 0, targetlist = 0x1b762c0, qual = 0x0,
lefttree = 0x1b75728, righttree = 0x0, initPlan = 0x0, extParam = 0x0, allParam = 0x0}
(gdb) p *estate
$2 = {type = T_EState, es_direction = ForwardScanDirection, es_snapshot = 0x1b31e10, es_crosscheck_snapshot = 0x0,
es_range_table = 0x1b75c00, es_plannedstmt = 0x1b77d58,
es_sourceText = 0x1a8ceb8 "select dw.*,grjf.grbh,grjf.xm,grjf.ny,grjf.je \nfrom t_dwxx dw,lateral (select gr.grbh,gr.xm,jf.ny,jf.je \n", ' ' <repeats 24 times>, "from t_grxx gr inner join t_jfxx jf \n", ' ' <repeats 34 times>...,
es_junkFilter = 0x0, es_output_cid = 0, es_result_relations = 0x0, es_num_result_relations = 0,
es_result_relation_info = 0x0, es_root_result_relations = 0x0, es_num_root_result_relations = 0,
es_tuple_routing_result_relations = 0x0, es_trig_target_relations = 0x0, es_trig_tuple_slot = 0x0,
es_trig_oldtup_slot = 0x0, es_trig_newtup_slot = 0x0, es_param_list_info = 0x0, es_param_exec_vals = 0x0,
es_queryEnv = 0x0, es_query_cxt = 0x1b78e30, es_tupleTable = 0x0, es_rowMarks = 0x0, es_processed = 0, es_lastoid = 0,
es_top_eflags = 16, es_instrument = 0, es_finished = false, es_exprcontexts = 0x0, es_subplanstates = 0x0,
es_auxmodifytables = 0x0, es_per_tuple_exprcontext = 0x0, es_epqTuple = 0x0, es_epqTupleSet = 0x0, es_epqScanDone = 0x0,
es_use_parallel_mode = false, es_query_dsa = 0x0, es_jit_flags = 0, es_jit = 0x0, es_jit_worker_instr = 0x0}检查堆栈
(gdb) n
156 check_stack_depth();进入相应的处理逻辑
158 switch (nodeTag(node))
(gdb)
313 result = (PlanState *) ExecInitSort((Sort *) node,返回结果
(gdb) p *result
$3 = {type = 11084746, plan = 0x69900000699, state = 0x0, ExecProcNode = 0x0, ExecProcNodeReal = 0x0,
instrument = 0x1000000000000, worker_instrument = 0x0, worker_jit_instrument = 0x200000001, qual = 0x0, lefttree = 0x0,
righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x7f7f7f7f7f7f7f7e, ps_ResultTupleSlot = 0x7f7f7f7f7f7f7f7f,
ps_ExprContext = 0x7f7f7f7f7f7f7f7f, ps_ProjInfo = 0x80, scandesc = 0x0}设置断点,进入ExecSetExecProcNode
(gdb) b ExecSetExecProcNode
Breakpoint 2 at 0x6e41a1: file execProcnode.c, line 414.
(gdb) c
Continuing.ExecSetExecProcNode->输入参数,function为ExecSeqScan,在实际执行时调用此函数
(gdb) p *function
$5 = {TupleTableSlot *(struct PlanState *)} 0x714d59 <ExecSeqScan>
(gdb) p *node
$6 = {type = T_SeqScanState, plan = 0x1b74f58, state = 0x1b78f48, ExecProcNode = 0x714d59 <ExecSeqScan>,
ExecProcNodeReal = 0x0, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0, qual = 0x0,
lefttree = 0x0, righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0, ps_ResultTupleSlot = 0x1b7a9c0,
ps_ExprContext = 0x1b7a5a8, ps_ProjInfo = 0x1b7aa80, scandesc = 0x7f07174f5308}回到最上层的ExecInitNode,initPlan为NULL
(gdb)
ExecInitNode (node=0x1b74f58, estate=0x1b78f48, eflags=16) at execProcnode.c:379
379 subps = NIL;
(gdb)
380 foreach(l, node->initPlan)
(gdb) p *node
$7 = {type = T_SeqScan, startup_cost = 0, total_cost = 1726, plan_rows = 100000, plan_width = 16, parallel_aware = false,
parallel_safe = true, plan_node_id = 5, targetlist = 0x1b74e20, qual = 0x0, lefttree = 0x0, righttree = 0x0,
initPlan = 0x0, extParam = 0x0, allParam = 0x0}完成调用
(gdb) n
389 result->initPlan = subps;
(gdb)
392 if (estate->es_instrument)
(gdb)
395 return result;
(gdb)
396 }下面重点考察ExecInitSeqScan和ExecInitHashJoin,首先是ExecInitHashJoin
ExecInitHashJoin->
(gdb) b ExecInitSeqScan
Breakpoint 3 at 0x714daf: file nodeSeqscan.c, line 148.
(gdb) b ExecInitHashJoin
Breakpoint 4 at 0x701f60: file nodeHashjoin.c, line 604.
(gdb) c
Continuing.
Breakpoint 4, ExecInitHashJoin (node=0x1b737c0, estate=0x1b78f48, eflags=16) at nodeHashjoin.c:604
warning: Source file is more recent than executable.
604 Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));ExecInitHashJoin->校验并初始化
604 Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
(gdb) n
609 hjstate = makeNode(HashJoinState);
(gdb)
610 hjstate->js.ps.plan = (Plan *) node;
(gdb)
611 hjstate->js.ps.state = estate;
(gdb)
618 hjstate->js.ps.ExecProcNode = ExecHashJoin;
(gdb)
619 hjstate->js.jointype = node->join.jointype;
(gdb)
626 ExecAssignExprContext(estate, &hjstate->js.ps);ExecInitHashJoin->初步的数据结构体
(gdb) p *hjstate
$8 = {js = {ps = {type = T_HashJoinState, plan = 0x1b737c0, state = 0x1b78f48, ExecProcNode = 0x701efa <ExecHashJoin>,
ExecProcNodeReal = 0x0, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0, qual = 0x0,
lefttree = 0x0, righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0, ps_ResultTupleSlot = 0x0,
ps_ExprContext = 0x0, ps_ProjInfo = 0x0, scandesc = 0x0}, jointype = JOIN_INNER, single_match = false,
joinqual = 0x0}, hashclauses = 0x0, hj_OuterHashKeys = 0x0, hj_InnerHashKeys = 0x0, hj_HashOperators = 0x0,
hj_HashTable = 0x0, hj_CurHashValue = 0, hj_CurBucketNo = 0, hj_CurSkewBucketNo = 0, hj_CurTuple = 0x0,
hj_OuterTupleSlot = 0x0, hj_HashTupleSlot = 0x0, hj_NullOuterTupleSlot = 0x0, hj_NullInnerTupleSlot = 0x0,
hj_FirstOuterTupleSlot = 0x0, hj_JoinState = 0, hj_MatchedOuter = false, hj_OuterNotEmpty = false}ExecInitHashJoin->获取HashJoin的outer&inner(PG视为Hash节点)
outerNode为HashJoin,innerNode为Hash
(gdb) n
635 outerNode = outerPlan(node);
gdb) n
636 hashNode = (Hash *) innerPlan(node);
(gdb)
638 outerPlanState(hjstate) = ExecInitNode(outerNode, estate, eflags);
(gdb) p *node
$9 = {join = {plan = {type = T_HashJoin, startup_cost = 3754, total_cost = 8689.6112499999999, plan_rows = 100000,
plan_width = 47, parallel_aware = false, parallel_safe = true, plan_node_id = 1, targetlist = 0x1b74cc8, qual = 0x0,
lefttree = 0x1b73320, righttree = 0x1b73728, initPlan = 0x0, extParam = 0x0, allParam = 0x0}, jointype = JOIN_INNER,
inner_unique = true, joinqual = 0x0}, hashclauses = 0x1b74bb8}
(gdb) p *outerNode
$12 = {type = T_HashJoin, startup_cost = 3465, total_cost = 8138, plan_rows = 100000, plan_width = 31,
parallel_aware = false, parallel_safe = true, plan_node_id = 2, targetlist = 0x1b75588, qual = 0x0, lefttree = 0x1b72da0,
righttree = 0x1b73288, initPlan = 0x0, extParam = 0x0, allParam = 0x0}
(gdb) p *hashNode
$11 = {plan = {type = T_Hash, startup_cost = 164, total_cost = 164, plan_rows = 10000, plan_width = 20,
parallel_aware = false, parallel_safe = true, plan_node_id = 6, targetlist = 0x1b75c08, qual = 0x0,
lefttree = 0x1b73570, righttree = 0x0, initPlan = 0x0, extParam = 0x0, allParam = 0x0}, skewTable = 16742,
skewColumn = 1, skewInherit = false, rows_total = 0}ExecInitHashJoin->进入outerNode的HashJoin,直接跳过
(gdb) n
Breakpoint 4, ExecInitHashJoin (node=0x1b73320, estate=0x1b78f48, eflags=16) at nodeHashjoin.c:604
604 Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
(gdb) finish
Run till exit from #0 ExecInitHashJoin (node=0x1b73320, estate=0x1b78f48, eflags=16) at nodeHashjoin.c:604ExecInitHashJoin->进入innerNode的调用(ExecInitSeqScan)
Breakpoint 3, ExecInitSeqScan (node=0x1b72da0, estate=0x1b78f48, eflags=16) at nodeSeqscan.c:148
warning: Source file is more recent than executable.
148 Assert(outerPlan(node) == NULL);
(gdb)ExecInitSeqScan
ExecInitSeqScan->执行校验,并创建Node.
注意:ExecProcNode=ExecSeqScan
148 Assert(outerPlan(node) == NULL);
(gdb) n
149 Assert(innerPlan(node) == NULL);
(gdb)
154 scanstate = makeNode(SeqScanState);
(gdb)
155 scanstate->ss.ps.plan = (Plan *) node;
(gdb)
156 scanstate->ss.ps.state = estate;
(gdb)
157 scanstate->ss.ps.ExecProcNode = ExecSeqScan;
(gdb)
164 ExecAssignExprContext(estate, &scanstate->ss.ps);
(gdb) p *scanstate
$1 = {ss = {ps = {type = T_SeqScanState, plan = 0x1b72da0, state = 0x1b78f48, ExecProcNode = 0x714d59 <ExecSeqScan>,
ExecProcNodeReal = 0x0, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0, qual = 0x0,
lefttree = 0x0, righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0, ps_ResultTupleSlot = 0x0,
ps_ExprContext = 0x0, ps_ProjInfo = 0x0, scandesc = 0x0}, ss_currentRelation = 0x0, ss_currentScanDesc = 0x0,
ss_ScanTupleSlot = 0x0}, pscan_len = 0}ExecInitSeqScan->打开Relation
gdb) n
173 ExecOpenScanRelation(estate,
(gdb)
172 scanstate->ss.ss_currentRelation =
(gdb)
179 RelationGetDescr(scanstate->ss.ss_currentRelation));
(gdb) p *scanstate->ss.ss_currentRelation
$3 = {rd_node = {spcNode = 1663, dbNode = 16402, relNode = 16747}, rd_smgr = 0x1b64650, rd_refcnt = 1, rd_backend = -1,
rd_islocaltemp = false, rd_isnailed = false, rd_isvalid = true, rd_indexvalid = 1 '\001', rd_statvalid = true,
rd_createSubid = 0, rd_newRelfilenodeSubid = 0, rd_rel = 0x7f07174f5c78, rd_att = 0x7f07174f5d90, rd_id = 16747,
rd_lockInfo = {lockRelId = {relId = 16747, dbId = 16402}}, rd_rules = 0x0, rd_rulescxt = 0x0, trigdesc = 0x0,
rd_rsdesc = 0x0, rd_fkeylist = 0x0, rd_fkeyvalid = false, rd_partkeycxt = 0x0, rd_partkey = 0x0, rd_pdcxt = 0x0,
rd_partdesc = 0x0, rd_partcheck = 0x0, rd_indexlist = 0x7f0717447328, rd_oidindex = 0, rd_pkindex = 0,
rd_replidindex = 0, rd_statlist = 0x0, rd_indexattr = 0x0, rd_projindexattr = 0x0, rd_keyattr = 0x0, rd_pkattr = 0x0,
rd_idattr = 0x0, rd_projidx = 0x0, rd_pubactions = 0x0, rd_options = 0x0, rd_index = 0x0, rd_indextuple = 0x0,
rd_amhandler = 0, rd_indexcxt = 0x0, rd_amroutine = 0x0, rd_opfamily = 0x0, rd_opcintype = 0x0, rd_support = 0x0,
rd_supportinfo = 0x0, rd_indoption = 0x0, rd_indexprs = 0x0, rd_indpred = 0x0, rd_exclops = 0x0, rd_exclprocs = 0x0,
rd_exclstrats = 0x0, rd_amcache = 0x0, rd_indcollation = 0x0, rd_fdwroutine = 0x0, rd_toastoid = 0,
pgstat_info = 0x1b0b6c0}ExecInitSeqScan->使用合适的rowtype打开slot(初始化ScanTupleSlot)
(gdb)
178 ExecInitScanTupleSlot(estate, &scanstate->ss,
(gdb)
184 ExecInitResultTupleSlotTL(estate, &scanstate->ss.ps);
(gdb) p *scanstate->ss.ss_ScanTupleSlot
$4 = {type = T_TupleTableSlot, tts_isempty = true, tts_shouldFree = false, tts_shouldFreeMin = false, tts_slow = false,
tts_tuple = 0x0, tts_tupleDescriptor = 0x7f07174f5d90, tts_mcxt = 0x1b78e30, tts_buffer = 0, tts_nvalid = 0,
tts_values = 0x1b79a98, tts_isnull = 0x1b79ab0, tts_mintuple = 0x0, tts_minhdr = {t_len = 0, t_self = {ip_blkid = {
bi_hi = 0, bi_lo = 0}, ip_posid = 0}, t_tableOid = 0, t_data = 0x0}, tts_off = 0, tts_fixedTupleDescriptor = true}
(gdb)ExecInitSeqScan->初始化结果类型和投影
(gdb) n
185 ExecAssignScanProjectionInfo(&scanstate->ss);
(gdb)
191 ExecInitQual(node->plan.qual, (PlanState *) scanstate);
(gdb) p *scanstate
$5 = {ss = {ps = {type = T_SeqScanState, plan = 0x1b72da0, state = 0x1b78f48, ExecProcNode = 0x714d59 <ExecSeqScan>,
ExecProcNodeReal = 0x0, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0, qual = 0x0,
lefttree = 0x0, righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0, ps_ResultTupleSlot = 0x1b79d48,
ps_ExprContext = 0x1b79978, ps_ProjInfo = 0x1b79e08, scandesc = 0x7f07174f5d90}, ss_currentRelation = 0x7f07174f5a60,
ss_currentScanDesc = 0x0, ss_ScanTupleSlot = 0x1b79a38}, pscan_len = 0}
(gdb) p *scanstate->ss.ps.ps_ResultTupleSlot
$6 = {type = T_TupleTableSlot, tts_isempty = true, tts_shouldFree = false, tts_shouldFreeMin = false, tts_slow = false,
tts_tuple = 0x0, tts_tupleDescriptor = 0x1b79b30, tts_mcxt = 0x1b78e30, tts_buffer = 0, tts_nvalid = 0,
tts_values = 0x1b79da8, tts_isnull = 0x1b79dc0, tts_mintuple = 0x0, tts_minhdr = {t_len = 0, t_self = {ip_blkid = {
bi_hi = 0, bi_lo = 0}, ip_posid = 0}, t_tableOid = 0, t_data = 0x0}, tts_off = 0, tts_fixedTupleDescriptor = true}
(gdb) p *scanstate->ss.ps.ps_ProjInfo
$7 = {type = T_ProjectionInfo, pi_state = {tag = {type = T_ExprState}, flags = 6 '\006', resnull = false, resvalue = 0,
resultslot = 0x1b79d48, steps = 0x1b79ea0, evalfunc = 0x6d104b <ExecInterpExprStillValid>, expr = 0x1b72c68,
evalfunc_private = 0x6cec02 <ExecInterpExpr>, steps_len = 5, steps_alloc = 16, parent = 0x1b79860, ext_params = 0x0,
innermost_caseval = 0x0, innermost_casenull = 0x0, innermost_domainval = 0x0, innermost_domainnull = 0x0},
pi_exprContext = 0x1b79978}ExecInitSeqScan->初始化子条件表达式(为NULL),返回结果
(gdb) n
190 scanstate->ss.ps.qual =
(gdb)
193 return scanstate;
(gdb) p *scanstate->ss.ps.qual
Cannot access memory at address 0x0ExecInitSeqScan->回到ExecInitNode for Node SeqScan
(gdb) n
194 }
(gdb)
ExecInitNode (node=0x1b72da0, estate=0x1b78f48, eflags=16) at execProcnode.c:209
warning: Source file is more recent than executable.
209 break;ExecInitSeqScan->回到ExecInitNode,结束调用
(gdb) n
379 subps = NIL;
(gdb)
380 foreach(l, node->initPlan)
(gdb)
389 result->initPlan = subps;
(gdb)
392 if (estate->es_instrument)
(gdb)
395 return result;
(gdb)
396 }
(gdb)ExecInitSeqScan->回到ExecInitHashJoin
(gdb)
ExecInitHashJoin (node=0x1b73320, estate=0x1b78f48, eflags=16) at nodeHashjoin.c:639
639 outerDesc = ExecGetResultType(outerPlanState(hjstate));ExecInitHashJoin
ExecInitHashJoin->完成outer relation的处理,开始处理inner relation(递归调用ExecInitNode)
639 outerDesc = ExecGetResultType(outerPlanState(hjstate));
(gdb) n
640 innerPlanState(hjstate) = ExecInitNode((Plan *) hashNode, estate, eflags);
(gdb)
Breakpoint 2, ExecInitSeqScan (node=0x1b72ff0, estate=0x1b78f48, eflags=16) at nodeSeqscan.c:148
148 Assert(outerPlan(node) == NULL);
(gdb) del 2
(gdb) finish
Run till exit from #0 ExecInitSeqScan (node=0x1b72ff0, estate=0x1b78f48, eflags=16) at nodeSeqscan.c:148
0x00000000006e3cd2 in ExecInitNode (node=0x1b72ff0, estate=0x1b78f48, eflags=16) at execProcnode.c:207
207 result = (PlanState *) ExecInitSeqScan((SeqScan *) node,
Value returned is $10 = (SeqScanState *) 0x1b7a490
(gdb)
...
(gdb) n
641 innerDesc = ExecGetResultType(innerPlanState(hjstate));ExecInitHashJoin->查看outerDesc和innerDesc
(gdb) p *outerDesc
$14 = {natts = 3, tdtypeid = 2249, tdtypmod = -1, tdhasoid = false, tdrefcount = -1, constr = 0x0, attrs = 0x1b79b50}
(gdb) p *innerDesc
$15 = {natts = 3, tdtypeid = 2249, tdtypmod = -1, tdhasoid = false, tdrefcount = -1, constr = 0x0, attrs = 0x1b7ab38}
(gdb)ExecInitHashJoin->初始化节点slot/类型/投影/元组表等
(gdb) n
647 ExecAssignProjectionInfo(&hjstate->js.ps, NULL);
(gdb)
652 hjstate->hj_OuterTupleSlot = ExecInitExtraTupleSlot(estate, outerDesc);
(gdb)
657 hjstate->js.single_match = (node->join.inner_unique ||
(gdb)
658 node->join.jointype == JOIN_SEMI);
(gdb) p *hjstate
$16 = {js = {ps = {type = T_HashJoinState, plan = 0x1b73320, state = 0x1b78f48, ExecProcNode = 0x701efa <ExecHashJoin>,
ExecProcNodeReal = 0x0, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0, qual = 0x0,
lefttree = 0x1b79860, righttree = 0x1b7a2b8, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0,
ps_ResultTupleSlot = 0x1b7ad30, ps_ExprContext = 0x1b797a0, ps_ProjInfo = 0x1b85bf8, scandesc = 0x0},
jointype = JOIN_INNER, single_match = false, joinqual = 0x0}, hashclauses = 0x0, hj_OuterHashKeys = 0x0,
hj_InnerHashKeys = 0x0, hj_HashOperators = 0x0, hj_HashTable = 0x0, hj_CurHashValue = 0, hj_CurBucketNo = 0,
hj_CurSkewBucketNo = 0, hj_CurTuple = 0x0, hj_OuterTupleSlot = 0x1b860a8, hj_HashTupleSlot = 0x0,
hj_NullOuterTupleSlot = 0x0, hj_NullInnerTupleSlot = 0x0, hj_FirstOuterTupleSlot = 0x0, hj_JoinState = 0,
hj_MatchedOuter = false, hj_OuterNotEmpty = false}
(gdb) p *hjstate->js.ps.ps_ResultTupleSlot #结果TupleSlot
$20 = {type = T_TupleTableSlot, tts_isempty = true, tts_shouldFree = false, tts_shouldFreeMin = false, tts_slow = false,
tts_tuple = 0x0, tts_tupleDescriptor = 0x1b857b8, tts_mcxt = 0x1b78e30, tts_buffer = 0, tts_nvalid = 0,
tts_values = 0x1b7ad90, tts_isnull = 0x1b7adb8, tts_mintuple = 0x0, tts_minhdr = {t_len = 0, t_self = {ip_blkid = {
bi_hi = 0, bi_lo = 0}, ip_posid = 0}, t_tableOid = 0, t_data = 0x0}, tts_off = 0, tts_fixedTupleDescriptor = true}
(gdb) p *hjstate->js.ps.ps_ProjInfo #投影
$18 = {type = T_ProjectionInfo, pi_state = {tag = {type = T_ExprState}, flags = 6 '\006', resnull = false, resvalue = 0,
resultslot = 0x1b7ad30, steps = 0x1b85c90, evalfunc = 0x6d104b <ExecInterpExprStillValid>, expr = 0x1b75588,
evalfunc_private = 0x6cec02 <ExecInterpExpr>, steps_len = 8, steps_alloc = 16, parent = 0x1b79588, ext_params = 0x0,
innermost_caseval = 0x0, innermost_casenull = 0x0, innermost_domainval = 0x0, innermost_domainnull = 0x0},
pi_exprContext = 0x1b797a0}
(gdb) p *hjstate->hj_OuterTupleSlot #元组slot
$19 = {type = T_TupleTableSlot, tts_isempty = true, tts_shouldFree = false, tts_shouldFreeMin = false, tts_slow = false,
tts_tuple = 0x0, tts_tupleDescriptor = 0x1b79b30, tts_mcxt = 0x1b78e30, tts_buffer = 0, tts_nvalid = 0,
tts_values = 0x1b86108, tts_isnull = 0x1b86120, tts_mintuple = 0x0, tts_minhdr = {t_len = 0, t_self = {ip_blkid = {
bi_hi = 0, bi_lo = 0}, ip_posid = 0}, t_tableOid = 0, t_data = 0x0}, tts_off = 0, tts_fixedTupleDescriptor = true}
(gdb) n
657 hjstate->js.single_match = (node->join.inner_unique ||
(gdb)
661 switch (node->join.jointype)
(gdb) p hjstate->js.single_match
$21 = falseExecInitHashJoin->配置外连接的NULL元组(不需要)
(gdb) n
665 break;ExecInitHashJoin->获取Hash操作的State,注意ExecProcNode是一个包装器(ExecProcNodeFirst),实际的函数是ExecHash
(gdb)
694 HashState *hashstate = (HashState *) innerPlanState(hjstate);
(gdb)
695 TupleTableSlot *slot = hashstate->ps.ps_ResultTupleSlot;
(gdb) n
697 hjstate->hj_HashTupleSlot = slot;
(gdb)
(gdb) p *hashstate
$22 = {ps = {type = T_HashState, plan = 0x1b73288, state = 0x1b78f48, ExecProcNode = 0x6e41bb <ExecProcNodeFirst>,
ExecProcNodeReal = 0x6fb5f2 <ExecHash>, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0,
qual = 0x0, lefttree = 0x1b7a490, righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0,
ps_ResultTupleSlot = 0x1b856f8, ps_ExprContext = 0x1b7a3d0, ps_ProjInfo = 0x0, scandesc = 0x0}, hashtable = 0x0,
hashkeys = 0x0, shared_info = 0x0, hinstrument = 0x0, parallel_state = 0x0}ExecInitHashJoin->初始化(子)表达式,均为NULL
(gdb) n
697 hjstate->hj_HashTupleSlot = slot;
(gdb)
704 ExecInitQual(node->join.plan.qual, (PlanState *) hjstate);
(gdb) n
703 hjstate->js.ps.qual =
(gdb)
706 ExecInitQual(node->join.joinqual, (PlanState *) hjstate);
(gdb)
705 hjstate->js.joinqual =
(gdb)
708 ExecInitQual(node->hashclauses, (PlanState *) hjstate);
(gdb)
707 hjstate->hashclauses =
(gdb)
713 hjstate->hj_HashTable = NULL;
(gdb)
714 hjstate->hj_FirstOuterTupleSlot = NULL;
(gdb)
716 hjstate->hj_CurHashValue = 0;
(gdb)
717 hjstate->hj_CurBucketNo = 0;
(gdb)
718 hjstate->hj_CurSkewBucketNo = INVALID_SKEW_BUCKET_NO;
(gdb)
719 hjstate->hj_CurTuple = NULL;
(gdb)
727 lclauses = NIL;
(gdb) p *hjstate->js.ps.qual
Cannot access memory at address 0x0
(gdb) p *hjstate->js.joinqual
Cannot access memory at address 0x0
(gdb)ExecInitHashJoin->将哈希子句解构为外部和内部参数值，以便能够分别计算这些子表达式;还可以列出哈希运算符oid，以便查找要使用的哈希函数.
...
(gdb) p *hjstate->hj_OuterHashKeys
$25 = {type = T_List, length = 1, head = 0x1b86f98, tail = 0x1b86f98}
(gdb) p *hjstate->hj_InnerHashKeys
$26 = {type = T_List, length = 1, head = 0x1b87708, tail = 0x1b87708}
(gdb) p *hjstate->hj_HashOperators
$27 = {type = T_OidList, length = 1, head = 0x1b87768, tail = 0x1b87768}
(gdb)ExecInitHashJoin->完成调用
(gdb) n
746 hjstate->hj_JoinState = HJ_BUILD_HASHTABLE;
(gdb)
747 hjstate->hj_MatchedOuter = false;
(gdb)
748 hjstate->hj_OuterNotEmpty = false;
(gdb)
750 return hjstate;
(gdb)
751 }ExecInitHashJoin->最终结果(注意:这是最上层的HashJoin)
(gdb) p *hjstate
$28 = {js = {ps = {type = T_HashJoinState, plan = 0x1b73320, state = 0x1b78f48, ExecProcNode = 0x701efa <ExecHashJoin>,
ExecProcNodeReal = 0x0, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0, qual = 0x0,
lefttree = 0x1b79860, righttree = 0x1b7a2b8, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0,
ps_ResultTupleSlot = 0x1b7ad30, ps_ExprContext = 0x1b797a0, ps_ProjInfo = 0x1b85bf8, scandesc = 0x0},
jointype = JOIN_INNER, single_match = false, joinqual = 0x0}, hashclauses = 0x1b86168, hj_OuterHashKeys = 0x1b86fc0,
hj_InnerHashKeys = 0x1b87730, hj_HashOperators = 0x1b87790, hj_HashTable = 0x0, hj_CurHashValue = 0, hj_CurBucketNo = 0,
hj_CurSkewBucketNo = -1, hj_CurTuple = 0x0, hj_OuterTupleSlot = 0x1b860a8, hj_HashTupleSlot = 0x1b856f8,
hj_NullOuterTupleSlot = 0x0, hj_NullInnerTupleSlot = 0x0, hj_FirstOuterTupleSlot = 0x0, hj_JoinState = 1,
hj_MatchedOuter = false, hj_OuterNotEmpty = false}到此，关于“PostgreSQL中什么函数通过递归调用初始化计划树中的所有Plan节点”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注亿速云网站，小编会继续努力为大家带来更多实用的文章！
