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本篇內容主要講解“PostgreSQL中用于初始化查詢執行計劃函數是哪個”，感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷，實用性強。下面就讓小編來帶大家學習“PostgreSQL中用于初始化查詢執行計劃函數是哪個”吧!
EState
執行器在調用時的主要工作狀態
/* ----------------
* EState information
* EState信息
* Master working state for an Executor invocation
* 執行器在調用時的主要工作狀態
* ----------------
*/
typedef struct EState
{
NodeTag type;//標記
/* Basic state for all query types: */
//所有查詢類型的基礎狀態
ScanDirection es_direction; /* 掃描方向,如向前/后等;current scan direction */
Snapshot es_snapshot; /* 時間條件(通過快照實現);time qual to use */
Snapshot es_crosscheck_snapshot; /* RI的交叉檢查時間條件;crosscheck time qual for RI */
List *es_range_table; /* RTE鏈表;List of RangeTblEntry */
struct RangeTblEntry **es_range_table_array; /* 與鏈表等價的數組;equivalent array */
Index es_range_table_size; /* 數組大小;size of the range table arrays */
Relation *es_relations; /* RTE中的Relation指針,如未Open則為NULL;
* Array of per-range-table-entry Relation
* pointers, or NULL if not yet opened */
struct ExecRowMark **es_rowmarks; /* ExecRowMarks指針數組;
* Array of per-range-table-entry
* ExecRowMarks, or NULL if none */
PlannedStmt *es_plannedstmt; /* 計劃樹的最頂層PlannedStmt;link to top of plan tree */
const char *es_sourceText; /* QueryDesc中的源文本;Source text from QueryDesc */
JunkFilter *es_junkFilter; /* 最頂層的JunkFilter;top-level junk filter, if any */
/* If query can insert/delete tuples, the command ID to mark them with */
//如查詢可以插入/刪除元組,這里記錄了命令ID
CommandId es_output_cid;
/* Info about target table(s) for insert/update/delete queries: */
//insert/update/delete 目標表信息
ResultRelInfo *es_result_relations; /* ResultRelInfos數組;array of ResultRelInfos */
int es_num_result_relations; /* 數組大小;length of array */
ResultRelInfo *es_result_relation_info; /* 當前活動的數組;currently active array elt */
/*
* Info about the partition root table(s) for insert/update/delete queries
* targeting partitioned tables. Only leaf partitions are mentioned in
* es_result_relations, but we need access to the roots for firing
* triggers and for runtime tuple routing.
* 關于針對分區表的插入/更新/刪除查詢的分區根表的信息。
* 在es_result_relations中只提到了葉子分區，但是需要訪問根表來觸發觸發器和運行時元組路由。
*/
ResultRelInfo *es_root_result_relations; /* ResultRelInfos數組;array of ResultRelInfos */
int es_num_root_result_relations; /* 數組大小;length of the array */
/*
* The following list contains ResultRelInfos created by the tuple routing
* code for partitions that don't already have one.
* 下面的鏈表包含元組路由代碼為沒有分區的分區創建的ResultRelInfos。
*/
List *es_tuple_routing_result_relations;
/* Stuff used for firing triggers: */
//用于觸發觸發器的信息
List *es_trig_target_relations; /* 與觸發器相關的ResultRelInfos數組;trigger-only ResultRelInfos */
TupleTableSlot *es_trig_tuple_slot; /* 用于觸發器輸出的元組; for trigger output tuples */
TupleTableSlot *es_trig_oldtup_slot; /* 用于TriggerEnabled;for TriggerEnabled */
TupleTableSlot *es_trig_newtup_slot; /* 用于TriggerEnabled;for TriggerEnabled */
/* Parameter info: */
//參數信息
ParamListInfo es_param_list_info; /* 外部參數值; values of external params */
ParamExecData *es_param_exec_vals; /* 內部參數值; values of internal params */
QueryEnvironment *es_queryEnv; /* 查詢環境; query environment */
/* Other working state: */
//其他工作狀態
MemoryContext es_query_cxt; /* EState所在的內存上下文;per-query context in which EState lives */
List *es_tupleTable; /* TupleTableSlots鏈表;List of TupleTableSlots */
uint64 es_processed; /* 處理的元組數;# of tuples processed */
Oid es_lastoid; /* 最后處理的oid(用于INSERT命令);last oid processed (by INSERT) */
int es_top_eflags; /* 傳遞給ExecutorStart函數的eflags參數;eflags passed to ExecutorStart */
int es_instrument; /* InstrumentOption標記;OR of InstrumentOption flags */
bool es_finished; /* ExecutorFinish函數已完成則為T;true when ExecutorFinish is done */
List *es_exprcontexts; /* EState中的ExprContexts鏈表;List of ExprContexts within EState */
List *es_subplanstates; /* SubPlans的PlanState鏈表;List of PlanState for SubPlans */
List *es_auxmodifytables; /* 第二個ModifyTableStates鏈表;List of secondary ModifyTableStates */
/*
* this ExprContext is for per-output-tuple operations, such as constraint
* checks and index-value computations. It will be reset for each output
* tuple. Note that it will be created only if needed.
* 這個ExprContext用于元組輸出操作，例如約束檢查和索引值計算。它在每個輸出元組時重置。
* 注意，只有在需要時才會創建它。
*/
ExprContext *es_per_tuple_exprcontext;
/*
* These fields are for re-evaluating plan quals when an updated tuple is
* substituted in READ COMMITTED mode. es_epqTuple[] contains tuples that
* scan plan nodes should return instead of whatever they'd normally
* return, or NULL if nothing to return; es_epqTupleSet[] is true if a
* particular array entry is valid; and es_epqScanDone[] is state to
* remember if the tuple has been returned already. Arrays are of size
* es_range_table_size and are indexed by scan node scanrelid - 1.
* 這些字段用于在讀取提交模式中替換更新后的元組時重新評估計劃的條件quals。
* es_epqTuple[]數組包含掃描計劃節點應該返回的元組，而不是它們通常返回的任何值，如果沒有返回值，則為NULL;
* 如果特定數組條目有效，則es_epqTupleSet[]為真;es_epqScanDone[]是狀態，用來記住元組是否已經返回。
* 數組大小為es_range_table_size，通過掃描節點scanrelid - 1進行索引。
*/
HeapTuple *es_epqTuple; /* EPQ替換元組的數組;array of EPQ substitute tuples */
bool *es_epqTupleSet; /* 如EPQ元組已提供,則為T;true if EPQ tuple is provided */
bool *es_epqScanDone; /* 如EPQ元組已獲取,則為T;true if EPQ tuple has been fetched */
bool es_use_parallel_mode; /* 能否使用并行worker?can we use parallel workers? */
/* The per-query shared memory area to use for parallel execution. */
//用于并行執行的每個查詢共享內存區域。
struct dsa_area *es_query_dsa;
/*
* JIT information. es_jit_flags indicates whether JIT should be performed
* and with which options. es_jit is created on-demand when JITing is
* performed.
* JIT的信息。es_jit_flags指示是否應該執行JIT以及使用哪些選項。在執行JITing時，按需創建es_jit。
*
* es_jit_combined_instr is the the combined, on demand allocated,
* instrumentation from all workers. The leader's instrumentation is kept
* separate, and is combined on demand by ExplainPrintJITSummary().
* es_jit_combined_instr是所有workers根據需要分配的組合工具。
* leader的插裝是獨立的，根據需要由ExplainPrintJITSummary()組合。
*/
int es_jit_flags;
struct JitContext *es_jit;
struct JitInstrumentation *es_jit_worker_instr;
} EState;PlanState
PlanState是所有PlanState-type節點的虛父類(請參照面向對象的虛類)
/* ----------------
* PlanState node
* PlanState節點
* We never actually instantiate any PlanState nodes; this is just the common
* abstract superclass for all PlanState-type nodes.
* 實際上并沒有實例化PlanState節點;
* 這是所有PlanState-type節點的虛父類(請參照面向對象的虛類).
* ----------------
*/
typedef struct PlanState
{
NodeTag type;//節點類型
Plan *plan; /* 綁定的計劃節點;associated Plan node */
EState *state; /* 在執行期,指向top-level計劃的EState指針
* at execution time, states of individual
* nodes point to one EState for the whole
* top-level plan */
ExecProcNodeMtd ExecProcNode; /* 執行返回下一個元組的函數;function to return next tuple */
ExecProcNodeMtd ExecProcNodeReal; /* 如果ExecProcNode是封裝器,則這個變量是實際的函數;
* actual function, if above is a
* wrapper */
Instrumentation *instrument; /* 該節點可選的運行期統計信息;Optional runtime stats for this node */
WorkerInstrumentation *worker_instrument; /* 每個worker的instrumentation;per-worker instrumentation */
/* Per-worker JIT instrumentation */
//worker相應的JIT instrumentation
struct SharedJitInstrumentation *worker_jit_instrument;
/*
* Common structural data for all Plan types. These links to subsidiary
* state trees parallel links in the associated plan tree (except for the
* subPlan list, which does not exist in the plan tree).
* 所有Plan類型均有的數據結構;
* 這些鏈接到附屬狀態通過并行的方式鏈接到關聯的計劃樹中(除了計劃樹中不存在的子計劃鏈表)。
*/
ExprState *qual; /* 布爾條件;boolean qual condition */
struct PlanState *lefttree; /* 輸入的計劃樹,包括左樹&右樹;input plan tree(s) */
struct PlanState *righttree;
List *initPlan; /* 初始的SubPlanState節點鏈表;
* Init SubPlanState nodes (un-correlated expr
* subselects) */
List *subPlan; /* 在表達式中的subPlan鏈表;SubPlanState nodes in my expressions */
/*
* State for management of parameter-change-driven rescanning
* 參數改變驅動的重新掃描管理狀態
*/
Bitmapset *chgParam; /* changed Params的IDs集合(用于NestLoop連接);set of IDs of changed Params */
/*
* Other run-time state needed by most if not all node types.
* 大多數(如果不是所有)節點類型都需要的其他運行時狀態。
*/
TupleDesc ps_ResultTupleDesc; /* 節點的返回類型;node's return type */
TupleTableSlot *ps_ResultTupleSlot; /* 結果元組的slot;slot for my result tuples */
ExprContext *ps_ExprContext; /* 節點的表達式解析上下文;node's expression-evaluation context */
ProjectionInfo *ps_ProjInfo; /* 元組投影信息;info for doing tuple projection */
/*
* Scanslot's descriptor if known. This is a bit of a hack, but otherwise
* it's hard for expression compilation to optimize based on the
* descriptor, without encoding knowledge about all executor nodes.
* Scanslot描述符。
* 這有點笨拙，但是如果不編碼關于所有執行器節點的知識，那么表達式編譯就很難基于描述符進行優化。
*/
TupleDesc scandesc;
} PlanState;InitPlan函數初始化查詢執行計劃:打開文件/分配存儲空間并啟動規則管理器.
/* ----------------------------------------------------------------
* InitPlan
*
* Initializes the query plan: open files, allocate storage
* and start up the rule manager
* 初始化查詢執行計劃:打開文件/分配存儲空間并啟動規則管理器
* ----------------------------------------------------------------
*/
static void
InitPlan(QueryDesc *queryDesc, int eflags)
{
CmdType operation = queryDesc->operation;//命令類型
PlannedStmt *plannedstmt = queryDesc->plannedstmt;//已規劃的語句指針
Plan *plan = plannedstmt->planTree;//計劃樹
List *rangeTable = plannedstmt->rtable;//RTE鏈表
EState *estate = queryDesc->estate;//參見數據結構
PlanState *planstate;//參見數據結構
TupleDesc tupType;//參見數據結構
ListCell *l;
int i;
/*
* Do permissions checks
* 權限檢查
*/
ExecCheckRTPerms(rangeTable, true);
/*
* initialize the node's execution state
* 初始化節點執行狀態
*/
ExecInitRangeTable(estate, rangeTable);
estate->es_plannedstmt = plannedstmt;
/*
* Initialize ResultRelInfo data structures, and open the result rels.
* 初始化ResultRelInfo數據結構,打開結果rels
*/
if (plannedstmt->resultRelations)//存在resultRelations
{
List *resultRelations = plannedstmt->resultRelations;//結果Relation鏈表
int numResultRelations = list_length(resultRelations);//鏈表大小
ResultRelInfo *resultRelInfos;//ResultRelInfo數組
ResultRelInfo *resultRelInfo;//ResultRelInfo指針
resultRelInfos = (ResultRelInfo *)
palloc(numResultRelations * sizeof(ResultRelInfo));//分配空間
resultRelInfo = resultRelInfos;//指針賦值
foreach(l, resultRelations)//遍歷鏈表
{
Index resultRelationIndex = lfirst_int(l);
Relation resultRelation;
resultRelation = ExecGetRangeTableRelation(estate,
resultRelationIndex);//獲取結果Relation
InitResultRelInfo(resultRelInfo,
resultRelation,
resultRelationIndex,
NULL,
estate->es_instrument);//初始化ResultRelInfo
resultRelInfo++;//處理下一個ResultRelInfo
}
estate->es_result_relations = resultRelInfos;//賦值
estate->es_num_result_relations = numResultRelations;
/* es_result_relation_info is NULL except when within ModifyTable */
//設置es_result_relation_info為NULL,除了ModifyTable
estate->es_result_relation_info = NULL;
/*
* In the partitioned result relation case, also build ResultRelInfos
* for all the partitioned table roots, because we will need them to
* fire statement-level triggers, if any.
* 在分區結果關系這種情況中，還為所有分區表根構建ResultRelInfos，
* 因為我們需要它們觸發語句級別的觸發器(如果有的話)。
*/
if (plannedstmt->rootResultRelations)//存在rootResultRelations(并行處理)
{
int num_roots = list_length(plannedstmt->rootResultRelations);
resultRelInfos = (ResultRelInfo *)
palloc(num_roots * sizeof(ResultRelInfo));
resultRelInfo = resultRelInfos;
foreach(l, plannedstmt->rootResultRelations)
{
Index resultRelIndex = lfirst_int(l);
Relation resultRelDesc;
resultRelDesc = ExecGetRangeTableRelation(estate,
resultRelIndex);
InitResultRelInfo(resultRelInfo,
resultRelDesc,
resultRelIndex,
NULL,
estate->es_instrument);
resultRelInfo++;
}
estate->es_root_result_relations = resultRelInfos;
estate->es_num_root_result_relations = num_roots;
}
else
{
estate->es_root_result_relations = NULL;
estate->es_num_root_result_relations = 0;
}
}
else//不存在resultRelations
{
/*
* if no result relation, then set state appropriately
* 無resultRelations,設置相應的信息為NULL或為0
*/
estate->es_result_relations = NULL;
estate->es_num_result_relations = 0;
estate->es_result_relation_info = NULL;
estate->es_root_result_relations = NULL;
estate->es_num_root_result_relations = 0;
}
/*
* Next, build the ExecRowMark array from the PlanRowMark(s), if any.
* 下一步,利用PlanRowMark(s)創建ExecRowMark數組
*/
if (plannedstmt->rowMarks)//如存在rowMarks
{
estate->es_rowmarks = (ExecRowMark **)
palloc0(estate->es_range_table_size * sizeof(ExecRowMark *));
foreach(l, plannedstmt->rowMarks)
{
PlanRowMark *rc = (PlanRowMark *) lfirst(l);
Oid relid;
Relation relation;
ExecRowMark *erm;
/* ignore "parent" rowmarks; they are irrelevant at runtime */
if (rc->isParent)
continue;
/* get relation's OID (will produce InvalidOid if subquery) */
relid = exec_rt_fetch(rc->rti, estate)->relid;
/* open relation, if we need to access it for this mark type */
switch (rc->markType)
{
case ROW_MARK_EXCLUSIVE:
case ROW_MARK_NOKEYEXCLUSIVE:
case ROW_MARK_SHARE:
case ROW_MARK_KEYSHARE:
case ROW_MARK_REFERENCE:
relation = ExecGetRangeTableRelation(estate, rc->rti);
break;
case ROW_MARK_COPY:
/* no physical table access is required */
relation = NULL;
break;
default:
elog(ERROR, "unrecognized markType: %d", rc->markType);
relation = NULL; /* keep compiler quiet */
break;
}
/* Check that relation is a legal target for marking */
if (relation)
CheckValidRowMarkRel(relation, rc->markType);
erm = (ExecRowMark *) palloc(sizeof(ExecRowMark));
erm->relation = relation;
erm->relid = relid;
erm->rti = rc->rti;
erm->prti = rc->prti;
erm->rowmarkId = rc->rowmarkId;
erm->markType = rc->markType;
erm->strength = rc->strength;
erm->waitPolicy = rc->waitPolicy;
erm->ermActive = false;
ItemPointerSetInvalid(&(erm->curCtid));
erm->ermExtra = NULL;
Assert(erm->rti > 0 && erm->rti <= estate->es_range_table_size &&
estate->es_rowmarks[erm->rti - 1] == NULL);
estate->es_rowmarks[erm->rti - 1] = erm;
}
}
/*
* Initialize the executor's tuple table to empty.
* 初始化執行器的元組表為NULL
*/
estate->es_tupleTable = NIL;
estate->es_trig_tuple_slot = NULL;
estate->es_trig_oldtup_slot = NULL;
estate->es_trig_newtup_slot = NULL;
/* mark EvalPlanQual not active */
//標記EvalPlanQual為非活動模式
estate->es_epqTuple = NULL;
estate->es_epqTupleSet = NULL;
estate->es_epqScanDone = NULL;
/*
* Initialize private state information for each SubPlan. We must do this
* before running ExecInitNode on the main query tree, since
* ExecInitSubPlan expects to be able to find these entries.
* 為每個子計劃初始化私有狀態信息。
* 在主查詢樹上運行ExecInitNode之前，必須這樣做，因為ExecInitSubPlan希望能夠找到這些條目。
*/
Assert(estate->es_subplanstates == NIL);
i = 1; /* subplan索引計數從1開始;subplan indices count from 1 */
foreach(l, plannedstmt->subplans)//遍歷subplans
{
Plan *subplan = (Plan *) lfirst(l);
PlanState *subplanstate;
int sp_eflags;
/*
* A subplan will never need to do BACKWARD scan nor MARK/RESTORE. If
* it is a parameterless subplan (not initplan), we suggest that it be
* prepared to handle REWIND efficiently; otherwise there is no need.
* 子計劃永遠不需要執行向后掃描或標記/恢復。
* 如果它是一個無參數的子計劃(不是initplan)，建議它準備好有效地處理向后掃描;否則就沒有必要了。
*/
sp_eflags = eflags
& (EXEC_FLAG_EXPLAIN_ONLY | EXEC_FLAG_WITH_NO_DATA);//設置sp_eflags
if (bms_is_member(i, plannedstmt->rewindPlanIDs))
sp_eflags |= EXEC_FLAG_REWIND;
subplanstate = ExecInitNode(subplan, estate, sp_eflags);//執行Plan節點初始化過程
estate->es_subplanstates = lappend(estate->es_subplanstates,
subplanstate);
i++;
}
/*
* Initialize the private state information for all the nodes in the query
* tree. This opens files, allocates storage and leaves us ready to start
* processing tuples.
* 為查詢樹中的所有節點初始化私有狀態信息。
* 這將打開文件、分配存儲并讓我們準備好開始處理元組。
*/
planstate = ExecInitNode(plan, estate, eflags);//執行Plan節點初始化過程
/*
* Get the tuple descriptor describing the type of tuples to return.
* 獲取元組描述(返回的元組類型等)
*/
tupType = ExecGetResultType(planstate);
/*
* Initialize the junk filter if needed. SELECT queries need a filter if
* there are any junk attrs in the top-level tlist.
* 如需要，初始化垃圾過濾器。如果頂層的tlist中有任何垃圾標識，SELECT查詢需要一個過濾器。
*/
if (operation == CMD_SELECT)//SELECT命令
{
bool junk_filter_needed = false;
ListCell *tlist;
foreach(tlist, plan->targetlist)//遍歷tlist
{
TargetEntry *tle = (TargetEntry *) lfirst(tlist);
if (tle->resjunk)//如需要垃圾過濾器
{
junk_filter_needed = true;//設置為T
break;
}
}
if (junk_filter_needed)
{
JunkFilter *j;
j = ExecInitJunkFilter(planstate->plan->targetlist,
tupType->tdhasoid,
ExecInitExtraTupleSlot(estate, NULL));//初始化
estate->es_junkFilter = j;
/* Want to return the cleaned tuple type */
//期望返回已清理的元組類型
tupType = j->jf_cleanTupType;
}
}
//賦值
queryDesc->tupDesc = tupType;
queryDesc->planstate = planstate;
}測試腳本如下
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)
啟動gdb,設置斷點,進入InitPlan
(gdb) b InitPlan Breakpoint 1 at 0x6d9df2: file execMain.c, line 808. (gdb) c Continuing. Breakpoint 1, InitPlan (queryDesc=0x20838b8, eflags=16) at execMain.c:808 warning: Source file is more recent than executable. 808 CmdType operation = queryDesc->operation;
輸入參數
(gdb) p *queryDesc
$1 = {operation = CMD_SELECT, plannedstmt = 0x207e6c0,
sourceText = 0x1f96eb8 "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>...,
snapshot = 0x1fba8e0, crosscheck_snapshot = 0x0, dest = 0xf8f280 <donothingDR>, params = 0x0, queryEnv = 0x0,
instrument_options = 0, tupDesc = 0x0, estate = 0x207f898, planstate = 0x0, already_executed = false, totaltime = 0x0}
(gdb) p eflags
$2 = 16變量賦值,PlannedStmt的詳細數據結構先前章節已有解釋,請參見相關章節.
(gdb) n
809 PlannedStmt *plannedstmt = queryDesc->plannedstmt;
(gdb)
810 Plan *plan = plannedstmt->planTree;
(gdb)
811 List *rangeTable = plannedstmt->rtable;
(gdb) n
812 EState *estate = queryDesc->estate;
(gdb)
821 ExecCheckRTPerms(rangeTable, true);
(gdb) p *plannedstmt
$3 = {type = T_PlannedStmt, commandType = CMD_SELECT, queryId = 0, hasReturning = false, hasModifyingCTE = false,
canSetTag = true, transientPlan = false, dependsOnRole = false, parallelModeNeeded = false, jitFlags = 0,
planTree = 0x20788f8, rtable = 0x207c568, resultRelations = 0x0, nonleafResultRelations = 0x0, rootResultRelations = 0x0,
subplans = 0x0, rewindPlanIDs = 0x0, rowMarks = 0x0, relationOids = 0x207c5c8, invalItems = 0x0, paramExecTypes = 0x0,
utilityStmt = 0x0, stmt_location = 0, stmt_len = 313}
(gdb) p *plan
$4 = {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 = 0x207cc28, qual = 0x0,
lefttree = 0x207c090, righttree = 0x0, initPlan = 0x0, extParam = 0x0, allParam = 0x0}
(gdb) p *estate
$5 = {type = T_EState, es_direction = ForwardScanDirection, es_snapshot = 0x1fba8e0, es_crosscheck_snapshot = 0x0,
es_range_table = 0x0, es_plannedstmt = 0x0,
es_sourceText = 0x1f96eb8 "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 = 0x207f780, 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}RTE鏈表,一共有5個Item,3個基礎關系RTE_RELATION(1/3/4),1個RTE_SUBQUERY(2號),1個RTE_JOIN(5號)
(gdb) n
826 estate->es_range_table = rangeTable;
(gdb) p *rangeTable
$6 = {type = T_List, length = 5, head = 0x207c540, tail = 0x207cb28}
(gdb) p *(RangeTblEntry *)rangeTable->head->data.ptr_value
$9 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 16734, relkind = 114 'r', tablesample = 0x0, subquery = 0x0,
security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x0, functions = 0x0, funcordinality = false,
tablefunc = 0x0, values_lists = 0x0, ctename = 0x0, ctelevelsup = 0, self_reference = false, coltypes = 0x0,
coltypmods = 0x0, colcollations = 0x0, enrname = 0x0, enrtuples = 0, alias = 0x1f98448, eref = 0x1fbdd20,
lateral = false, inh = false, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x2054de8,
insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}
...沒有結果Relation,執行相應的處理邏輯
(gdb) 835 if (plannedstmt->resultRelations) (gdb) p plannedstmt->resultRelations $14 = (List *) 0x0 (gdb) n 922 estate->es_result_relations = NULL; (gdb) 923 estate->es_num_result_relations = 0; (gdb) 924 estate->es_result_relation_info = NULL; (gdb) 925 estate->es_root_result_relations = NULL; (gdb) 926 estate->es_num_root_result_relations = 0;
不存在rowMarks(for update)
(gdb) n 939 foreach(l, plannedstmt->rowMarks) (gdb) p plannedstmt->rowMarks $15 = (List *) 0x0 (gdb) p plannedstmt->rowMarks $16 = (List *) 0x0 (gdb) n 1000 estate->es_tupleTable = NIL;
執行賦值
(gdb) n 1001 estate->es_trig_tuple_slot = NULL; (gdb) 1002 estate->es_trig_oldtup_slot = NULL; ...
沒有subplans
(gdb) n 1017 foreach(l, plannedstmt->subplans) (gdb) p *plannedstmt->subplans Cannot access memory at address 0x0 (gdb) n
初始化節點(執行ExecInitNode)和獲取TupleType
(gdb) n
1046 planstate = ExecInitNode(plan, estate, eflags);
(gdb) n
1051 tupType = ExecGetResultType(planstate);
(gdb)
1057 if (operation == CMD_SELECT)
(gdb) p *planstate
$17 = {type = T_SortState, plan = 0x20788f8, state = 0x207f898, ExecProcNode = 0x6e41bb <ExecProcNodeFirst>,
ExecProcNodeReal = 0x716144 <ExecSort>, instrument = 0x0, worker_instrument = 0x0, worker_jit_instrument = 0x0,
qual = 0x0, lefttree = 0x207fbc8, righttree = 0x0, initPlan = 0x0, subPlan = 0x0, chgParam = 0x0,
ps_ResultTupleSlot = 0x2090dc0, ps_ExprContext = 0x0, ps_ProjInfo = 0x0, scandesc = 0x208e920}
(gdb) p tupType
$18 = (TupleDesc) 0x20909a8
(gdb) p *tupType
$19 = {natts = 7, tdtypeid = 2249, tdtypmod = -1, tdhasoid = false, tdrefcount = -1, constr = 0x0, attrs = 0x20909c8}判斷是否需要垃圾過濾器
(gdb) n 1059 bool junk_filter_needed = false; (gdb) 1062 foreach(tlist, plan->targetlist)
不需要junk filter
(gdb) 1073 if (junk_filter_needed)
賦值,結束調用
(gdb)
1087 queryDesc->tupDesc = tupType;
(gdb)
1088 queryDesc->planstate = planstate;
(gdb)
1089 }
(gdb)
standard_ExecutorStart (queryDesc=0x20838b8, eflags=16) at execMain.c:267
267 MemoryContextSwitchTo(oldcontext);
(gdb) p *queryDesc
$21 = {operation = CMD_SELECT, plannedstmt = 0x207e6c0,
sourceText = 0x1f96eb8 "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>...,
snapshot = 0x1fba8e0, crosscheck_snapshot = 0x0, dest = 0xf8f280 <donothingDR>, params = 0x0, queryEnv = 0x0,
instrument_options = 0, tupDesc = 0x20909a8, estate = 0x207f898, planstate = 0x207fab0, already_executed = false,
totaltime = 0x0}到此，相信大家對“PostgreSQL中用于初始化查詢執行計劃函數是哪個”有了更深的了解，不妨來實際操作一番吧！這里是億速云網站，更多相關內容可以進入相關頻道進行查詢，關注我們，繼續學習！
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