/*------------------------------------------------------------------------- * * preptlist.c-- * Routines to preprocess the parse tree target list * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * /usr/local/devel/pglite/cvs/src/backend/optimizer/prep/preptlist.c,v 1.12 1995/03/17 20:26:30 andrew Exp * *------------------------------------------------------------------------- */ #include #include "postgres.h" #include "nodes/pg_list.h" #include "nodes/relation.h" #include "nodes/primnodes.h" #include "nodes/parsenodes.h" #include "nodes/makefuncs.h" #include "utils/lsyscache.h" #include "utils/palloc.h" #include "parser/parsetree.h" /* for getrelid() */ #include "parser/catalog_utils.h" #include "optimizer/internal.h" #include "optimizer/prep.h" #include "optimizer/clauses.h" #include "optimizer/tlist.h" static List *expand_targetlist(List *tlist, Oid relid, int command_type, Index result_relation); static List *replace_matching_resname(List *new_tlist, List *old_tlist); static List *new_relation_targetlist(Oid relid, Index rt_index, NodeTag node_type); /* * preprocess-targetlist-- * Driver for preprocessing the parse tree targetlist. * * 1. Deal with appends and replaces by filling missing attributes * in the target list. * 2. Reset operator OIDs to the appropriate regproc ids. * * Returns the new targetlist. */ List * preprocess_targetlist(List *tlist, int command_type, Index result_relation, List *range_table) { List *expanded_tlist = NIL; Oid relid = InvalidOid; List *t_list = NIL; List *temp = NIL; if (result_relation>=1 && command_type != CMD_SELECT) { relid = getrelid(result_relation, range_table); } /* * for heap_formtuple to work, the targetlist must match the exact * order of the attributes. We also need to fill in the missing * attributes here. -ay 10/94 */ expanded_tlist = expand_targetlist(tlist, relid, command_type, result_relation); /* XXX should the fix-opids be this early?? */ /* was mapCAR */ foreach (temp,expanded_tlist) { TargetEntry *tle = lfirst(temp); if (tle->expr) fix_opid(tle->expr); } t_list = copyObject(expanded_tlist); /* ------------------ * for "replace" or "delete" queries, add ctid of the result * relation into the target list so that the ctid can get * propogate through the execution and in the end ExecReplace() * will find the right tuple to replace or delete. This * extra field will be removed in ExecReplace(). * For convinient, we append this extra field to the end of * the target list. * ------------------ */ if (command_type == CMD_UPDATE || command_type == CMD_DELETE) { TargetEntry *ctid; Resdom *resdom; Var *var; Name nameTemp = (Name)palloc(sizeof(NameData)); /* * XXX MakeResdom doesn't palloc any space it merely * assigns values and pointer to fields in the Resdom * struct. All pointers passed in must point to 'palloc'ed * space or the structure will contain garbage later. */ strcpy(&nameTemp->data[0], "ctid"); resdom = makeResdom(length(t_list) + 1, 27, 6, nameTemp, 0, 0, 1); var = makeVar(result_relation, -1, 27, result_relation, -1); ctid = makeNode(TargetEntry); ctid->resdom = resdom; ctid->expr = (Node *)var; t_list = lappend(t_list, ctid); } return(t_list); } /***************************************************************************** * * TARGETLIST EXPANSION * *****************************************************************************/ /* * expand-targetlist-- * Given a target list as generated by the parser and a result relation, * add targetlist entries for the attributes which have not been used. * * XXX This code is only supposed to work with unnested relations. * * 'tlist' is the original target list * 'relid' is the relid of the result relation * 'command' is the update command * * Returns the expanded target list, sorted in resno order. */ static List * expand_targetlist(List *tlist, Oid relid, int command_type, Index result_relation) { NodeTag node_type = T_Invalid; switch (command_type) { case CMD_INSERT: node_type = (NodeTag)T_Const; break; case CMD_UPDATE: node_type = (NodeTag)T_Var; break; } if(node_type != T_Invalid) { List *ntlist = new_relation_targetlist(relid, result_relation, node_type); return (replace_matching_resname(ntlist, tlist)); } else { return (tlist); } } static List * replace_matching_resname(List *new_tlist, List *old_tlist) { List *temp, *i; List *t_list = NIL; foreach (i,new_tlist) { TargetEntry *new_tle = (TargetEntry *)lfirst(i); TargetEntry *matching_old_tl = NULL; foreach (temp, old_tlist) { TargetEntry *old_tle = (TargetEntry *)lfirst(temp); old_tle = lfirst(temp); if (!namecmp(old_tle->resdom->resname, new_tle->resdom->resname)) { matching_old_tl = old_tle; break; } } if(matching_old_tl) { matching_old_tl->resdom->resno = new_tle->resdom->resno; t_list = lappend(t_list, matching_old_tl); } else { t_list = lappend(t_list, new_tle); } } /* * It is possible that 'old_tlist' has some negative * attributes (i.e. negative resnos). This only happens * if this is a replace/append command and we explicitly * specify a system attribute. Of course this is not a very good * idea if this is a user query, but on the other hand the rule * manager uses this mechanism to replace rule locks. * * So, copy all these entries to the end of the target list * and set their 'resjunk' value to 1 to show that these are * special attributes and have to be treated specially by the * executor! */ foreach (temp, old_tlist) { TargetEntry *old_tle, *new_tl; Resdom *newresno; old_tle = lfirst(temp); if (old_tle->resdom->resno < 0) { newresno = (Resdom*) copyObject((Node*)old_tle->resdom); newresno->resno = length(t_list) +1; newresno->resjunk = 1; new_tl = MakeTLE(newresno, old_tle->expr); t_list = lappend(t_list, new_tl); } } return (t_list); } /* * new-relation-targetlist-- * Generate a targetlist for the relation with relation OID 'relid' * and rangetable index 'rt-index'. * * Returns the new targetlist. */ static List * new_relation_targetlist(Oid relid, Index rt_index, NodeTag node_type) { AttrNumber attno; List *t_list = NIL; Name attname = (Name)NULL; Oid atttype = 0; int16 typlen = 0; bool attisset = false; for(attno=1; attno <= get_relnatts(relid); attno++) { attname = get_attname(relid, attno); atttype = get_atttype(relid, attno); /* * Since this is an append or replace, the size of any set * attribute is the size of the OID used to represent it. */ attisset = get_attisset(relid, attname); if (attisset) { typlen = tlen(type("oid")); } else { typlen = get_typlen(atttype); } switch (node_type) { case T_Const: { struct varlena *typedefault = get_typdefault(atttype); int temp = 0; Const *temp2 = (Const*)NULL; TargetEntry *temp3 = (TargetEntry *)NULL; if (typedefault==NULL) temp = 0; else temp = typlen; temp2 = makeConst (atttype, temp, (Datum)typedefault, (typedefault == (struct varlena *)NULL), /* XXX this is bullshit */ false, false /* not a set */); temp3 = MakeTLE (makeResdom(attno, atttype, typlen, attname, 0, (Oid)0, 0), (Node*)temp2); t_list = lappend(t_list,temp3); break; } case T_Var: { Var *temp_var = (Var*)NULL; TargetEntry *temp_list = NULL; temp_var = makeVar(rt_index, attno, atttype, rt_index, attno); temp_list = MakeTLE(makeResdom(attno, atttype, typlen, attname, 0, (Oid)0, 0), (Node*)temp_var); t_list = lappend(t_list,temp_list); break; } default: /* do nothing */ break; } } return(t_list); }