This section briefly describes the PostgreSQL corresponding data structures in Relation execution logic optimization: RangeTblEntry.
A data structure
RangeTblEntry
RTE may be sub-query ordinary table / FROM the results / JOIN statement, etc. (only explicit JOIN syntax produces RTE, the implicit connection generated by a plurality FROM items will not be generated. This is because we only need RTE to process SQL features, such as an external connection and an output connection column alias)
/ * -------------------- * RangeTblEntry -. * A range table is a List of RangeTblEntry nodes * RangeTblEntry node list * * A range table entry may represent a plain relation, a sub-select in * fROM, or the result of a JOIN clause. (only explicit JOIN syntax * produces an RTE, not the implicit join resulting from multiple fROM * items. This is because we only need the RTE to deal with SQL features * like outer joins and join-output-column aliasing.) Other special * RTE types also exist, as indicated by RTEKind. * RTE may be sub-query results / JOIN statement of ordinary table / FROM in. * (only display JOIN syntax produces RTE, the implicit connection generated by a plurality fROM items is not generated. * this is because we only need to deal with RTE SQL features, such as an external connection and connecting the output column alias) * * Note that we consider RTE_RELATION to cover anything that has a pg_class * entry. relkind distinguishes the sub-cases. * Note RTE_RELATION refer to the relatio stored in pg_class n information.
Second, the interpretation of the source
N/A
Third, tracking analysis
Test SQL statement:
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-- 用于测试的查询语句testdb=# select * from (testdb(# select t_dwxx.dwmc,t_grxx.grbh,t_grxx.xm,t_jfxx.ny,t_jfxx.jetestdb(# from t_dwxx inner join t_grxx on t_dwxx.dwbh = t_grxx.dwbhtestdb(# inner join t_jfxx on t_grxx.grbh = t_jfxx.grbhtestdb(# where t_dwxx.dwbh IN ('1001')testdb(# union alltestdb(# select t_dwxx.dwmc,t_grxx.grbh,t_grxx.xm,t_jfxx.ny,t_jfxx.jetestdb(# from t_dwxx inner join t_grxx on t_dwxx.dwbh = t_grxx.dwbhtestdb(# inner join t_jfxx on t_grxx.grbh = t_jfxx.grbhtestdb(# where t_dwxx.dwbh IN ('1002') testdb(# ) as rettestdb-# order by ret.grbhtestdb-# limit 4;
Sample data are as follows:
...(gdb) set $rtable=$query->rtable(gdb) p *$rtable$8 = {type = T_List, length = 3, head = 0x170be48, tail = 0x170f6b0}(gdb) p *(Node *)($rtable->head->data.ptr_value)$9 = {type = T_RangeTblEntry}(gdb) p *(RangeTblEntry *)($rtable->head->data.ptr_value)$10 = {type = T_RangeTblEntry, rtekind = RTE_SUBQUERY, relid = 0, relkind = 0 '\000', tablesample = 0x0, subquery = 0x1667500, 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 = 0x1666d40, eref = 0x170bc18, lateral = false, inh = true, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x0, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) set $rte=(RangeTblEntry *)($rtable->head->data.ptr_value)(gdb) p *$rte->subquery$12 = {type = T_Query, commandType = CMD_SELECT, querySource = QSRC_ORIGINAL, queryId = 0, canSetTag = true, utilityStmt = 0x0, resultRelation = 0, hasAggs = false, hasWindowFuncs = false, hasTargetSRFs = false, hasSubLinks = false, hasDistinctOn = false, hasRecursive = false, hasModifyingCTE = false, hasForUpdate = false, hasRowSecurity = false, cteList = 0x0, rtable = 0x16fe4e8, jointree = 0x170bbe8, targetList = 0x170b358, override = OVERRIDING_NOT_SET, onConflict = 0x0, returningList = 0x0, groupClause = 0x0, groupingSets = 0x0, havingQual = 0x0, windowClause = 0x0, distinctClause = 0x0, sortClause = 0x0, limitOffset = 0x0, limitCount = 0x0, rowMarks = 0x0, setOperations = 0x1667610, constraintDeps = 0x0, withCheckOptions = 0x0, stmt_location = 0, stmt_len = 0}(gdb) p *$rte->alias$13 = {type = T_Alias, aliasname = 0x1666d28 "ret", colnames = 0x0}(gdb) p *$rte->eref$14 = {type = T_Alias, aliasname = 0x170bc48 "ret", colnames = 0x170bcb8}(gdb) p *$rte->eref->colnames$15 = {type = T_List, length = 5, head = 0x170bc98, tail = 0x170be28}(gdb) p *(Node *)$rte->eref->colnames->head->data.ptr_value$16 = {type = T_String}(gdb) p *(Value *)$rte->eref->colnames->head->data.ptr_value$17 = {type = T_String, val = {ival = 24165472, str = 0x170bc60 "dwmc"}}---->subquery(gdb) p *(RangeTblEntry *)$rte->subquery->rtable->head->data.ptr_value$26 = {type = T_RangeTblEntry, rtekind = RTE_SUBQUERY, relid = 0, relkind = 0 '\000', tablesample = 0x0, subquery = 0x16faf98, 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 = 0x16fe240, eref = 0x16fe290, lateral = false, inh = false, inFromCl = false, requiredPerms = 0, checkAsUser = 0, selectedCols = 0x0, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) set $rte_sq_rte=((RangeTblEntry *)$rte->subquery->rtable->head->data.ptr_value)(gdb) p *(RangeTblEntry *)$rte_sq_rte->subquery->rtable->head->data.ptr_value$30 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 26754, 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 = 0x0, eref = 0x16677c0, lateral = false, inh = true, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x16fbda8, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) set $rte_sq_rte_sq_rte=(RangeTblEntry *)$rte_sq_rte->subquery->rtable->head->data.ptr_value(gdb) p *$rte_sq_rte_sq_rte$42 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 26754, 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 = 0x0, eref = 0x16677c0, lateral = false, inh = true, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x16fbda8, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) set $rte_sq_rte_sq_rtable=$rte_sq_rte->subquery->rtable(gdb) p *(RangeTblEntry *)($rte_sq_rte_sq_rtable->head->data.ptr_value)$60 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 26754, relkind = 114 'r', tablesample = 0x0, subquery = 0x0, security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x0, functions = 0x0, funcordinality = false, tablefunc = 0x0, values_lists = 0x0, ctename = 0x0, ctelevelsup = 0, self_reference = false, coltypes = 0x0, coltypmods = 0x0, colcollations = 0x0, enrname = 0x0, enrtuples = 0, alias = 0x0, eref = 0x16677c0, lateral = false, inh = true, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x16fbda8, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) p *(RangeTblEntry *)($rte_sq_rte_sq_rtable->head->next->data.ptr_value)$61 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 26757, relkind = 114 'r', tablesample = 0x0, subquery = 0x0, security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x0, functions = 0x0, funcordinality = false, tablefunc = 0x0, values_lists = 0x0, ctename = 0x0, ctelevelsup = 0, self_reference = false, coltypes = 0x0, coltypmods = 0x0, colcollations = 0x0, enrname = 0x0, enrtuples = 0, alias = 0x0, eref = 0x16fb4f0, lateral = false, inh = true, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x16fbe10, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) p *(RangeTblEntry *)($rte_sq_rte_sq_rtable->head->next->next->data.ptr_value)$62 = {type = T_RangeTblEntry, rtekind = RTE_JOIN, relid = 0, relkind = 0 '\000', tablesample = 0x0, subquery = 0x0, security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x16fbff8, functions = 0x0, funcordinality = false, tablefunc = 0x0, values_lists = 0x0, ctename = 0x0, ctelevelsup = 0, self_reference = false, coltypes = 0x0, coltypmods = 0x0, colcollations = 0x0, enrname = 0x0, enrtuples = 0, alias = 0x0, eref = 0x16fc318, lateral = false, inh = false, inFromCl = true, requiredPerms = 0, checkAsUser = 0, selectedCols = 0x0, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) p *(RangeTblEntry *)($rte_sq_rte_sq_rtable->head->next->next->next->data.ptr_value)$63 = {type = T_RangeTblEntry, rtekind = RTE_RELATION, relid = 26760, relkind = 114 'r', tablesample = 0x0, subquery = 0x0, security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x0, functions = 0x0, funcordinality = false, tablefunc = 0x0, values_lists = 0x0, ctename = 0x0, ctelevelsup = 0, self_reference = false, coltypes = 0x0, coltypmods = 0x0, colcollations = 0x0, enrname = 0x0, enrtuples = 0, alias = 0x0, eref = 0x16fc678, lateral = false, inh = true, inFromCl = true, requiredPerms = 2, checkAsUser = 0, selectedCols = 0x16fd1d0, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}(gdb) p *(RangeTblEntry *)($rte_sq_rte_sq_rtable->tail->data.ptr_value)$64 = {type = T_RangeTblEntry, rtekind = RTE_JOIN, relid = 0, relkind = 0 '\000', tablesample = 0x0, subquery = 0x0, security_barrier = false, jointype = JOIN_INNER, joinaliasvars = 0x16fd3b8, 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 = 0x16fd798, lateral = false, inh = false, inFromCl = true, requiredPerms = 0, checkAsUser = 0, selectedCols = 0x0, insertedCols = 0x0, updatedCols = 0x0, securityQuals = 0x0}
四、参考资料
N/A