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//Description:

//Create Date: 2020-01-18 23:17:48

//Author: channy

003_postgres_parse

postgres parse

生成分析树

//insert and select

pg_analyze_and_rewrite
	parse_analyze (analyze.c, parse_analyze_for_gram (ADB))
		transformTopLevelStmt (parsetree -> query)
			transformOptionalSelectInto
				transformStmt
					transformInsertStmt
						make_parsestate
						transformStmt
						transformInsertRow
						transformOnConflictClause
					transformSelectStmt
						transformStmt
							transformFromClause
								transformFromClauseItem
		transformFromAndWhere (ADB)
	pg_rewrite_query (query -> querytree_list)
		QueryRewrite	
			RewriteQuery
				fireRules
			fireRIRrules
				ApplyRetrieveRule

• 没有设定规则的情况下，重写树和分析树一样，没有改变

gdb 调试信息

//select * from debugtable, testtable where debugtable.id = testtable.id;

gdb after pg_plan_queries
(gdb) p *(Node *)(plantree_list->head.data->ptr_value)
$1 = {type = T_PlannedStmt}
(gdb) set $plan = (PlannedStmt *)((plantree_list->head.data->ptr_value))
(gdb) p *$plan
$2 = {type = T_PlannedStmt, commandType = CMD_SELECT, queryId = 0, 
hasReturning = false, hasModifyingCTE = false, canSetTag = true, 
transientPlan = false, dependsOnRole = false, 
parallelModeNeeded = false, jitFlags = 0, planTree = 0x21a56d8, 
rtable = 0x2271d18, resultRelations = 0x0, rootResultRelations = 0x0, 
subplans = 0x0, rewindPlanIDs = 0x0, rowMarks = 0x0, 
relationOids = 0x2271d78, invalItems = 0x0, paramExecTypes = 0x0, 
utilityStmt = 0x0, stmt_location = 0, stmt_len = 70}
(gdb) set $plantree = (Plan *)($plan->planTree)
(gdb) p *$plantree
$3 = {type = T_HashJoin, startup_cost = 13.15, 
total_cost = 40.994999999999997, plan_rows = 602, plan_width = 587, 
parallel_aware = false, parallel_safe = true, plan_node_id = 0, 
targetlist = 0x2272348, qual = 0x0, lefttree = 0x2270590, 
righttree = 0x2271b40, initPlan = 0x0, extParam = 0x0, allParam = 0x0}
(gdb) p *(Value *)($plan->rtable->head.data->ptr_value)
$5 = {type = T_RangeTblEntry, val = {ival = 16392, 
str = 0x7200004008 <error: Cannot access memory at address 0x7200004008>}}
(gdb) set $rtable = (RangeTblEntry *)($plan->rtable->head.data->ptr_value)(gdb) p *($rtable)
$6 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 16392, 
relkind = 114 'r', rellockmode = 1, tablesample = 0x0, subquery = 0x0, 
security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x0, 
functions = 0x0, funcordinality = false, tablefunc = 0x0, 
values_lists = 0x0, ctename = 0x0, ctelevelsup = 0, 
self_reference = false, coltypes = 0x0, coltypmods = 0x0, 
colcollations = 0x0, enrname = 0x0, enrtuples = 0, alias = 0x0, 
eref = 0x21a5a20, lateral = false, inh = false, inFromCl = true, 
requiredPerms = 2, checkAsUser = 0, selectedCols = 0x2294138, 
insertedCols = 0x0, updatedCols = 0x0, extraUpdatedCols = 0x0, 
securityQuals = 0x0}
(gdb) p *($plantree->lefttree)
$12 = {type = T_SeqScan, startup_cost = 0, 
total_cost = 18.600000000000001, plan_rows = 860, plan_width = 66, 
parallel_aware = false, parallel_safe = true, plan_node_id = 1, 
targetlist = 0x2271388, qual = 0x0, lefttree = 0x0, righttree = 0x0, 
initPlan = 0x0, extParam = 0x0, allParam = 0x0}
(gdb) p *($plantree->righttree)
$13 = {type = T_Hash, startup_cost = 11.4, total_cost = 11.4, 
plan_rows = 140, plan_width = 521, parallel_aware = false, 
parallel_safe = true, plan_node_id = 2, targetlist = 0x22728f0, 
qual = 0x0, lefttree = 0x2271728, righttree = 0x0, initPlan = 0x0, 
extParam = 0x0, allParam = 0x0}

//select * from testtable left join debugtable on testtable.id = debugtable.id;

exec_simple_query	
gdb after pg_parse_query
(gdb) p *((RawStmt *)(parsetree_list->head.data->ptr_value))->stmt
$6 = {type = T_SelectStmt}
(gdb) p *(SelectStmt *)((RawStmt *)(parsetree_list->head.data->ptr_value))->stmt
$7 = {type = T_SelectStmt, distinctClause = 0x0, intoClause = 0x0, 
targetList = 0x21a4fd8, fromClause = 0x21a5520, whereClause = 0x0, 
groupClause = 0x0, havingClause = 0x0, windowClause = 0x0, 
valuesLists = 0x0, sortClause = 0x0, limitOffset = 0x0, 
limitCount = 0x0, lockingClause = 0x0, withClause = 0x0, 
op = SETOP_NONE, all = false, larg = 0x0, rarg = 0x0}
(gdb) set $stmt = (SelectStmt *)((RawStmt *)(parsetree_list->head.data->ptr_value))->stmt
(gdb) p *(Value *)($stmt->targetList->head.data->ptr_value)
$15 = {type = T_ResTarget, val = {ival = 0, str = 0x0}}
(gdb) p *(Value *)($stmt->fromClause->head.data->ptr_value)
$16 = {type = T_JoinExpr, val = {ival = 0, str = 0x0}}
(gdb) set $from = (JoinExpr *)($stmt->fromClause->head.data->ptr_value)
(gdb) p *(RangeVar *)($from->larg)
$19 = {type = T_RangeVar, catalogname = 0x0, schemaname = 0x0, 
relname = 0x21a5010 "testtable", inh = true, relpersistence = 112 'p', 
alias = 0x0, location = 14}

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