Re: Allow arbitrary levels of analyze/rewriting

Your patch has been added to the PostgreSQL unapplied patches list at:

http://candle.pha.pa.us/cgi-bin/pgpatches

I will try to apply it within the next 48 hours.

---------------------------------------------------------------------------

Fernando Nasser wrote:
> Hi,
>
> This patch will allow arbitrary levels of analyze / rewriting
> by making the static variables extra_before and extra_after
> automatic so we can use recursion.
>
> It gets much easier to generate extra commands now, and one can rest
> assured that the extra commands will be properly analyzed/rewritten.
>
>
> Without this patch, if a command produced by transformation tries to
> use these static lists their first contents would be lost with
> unpredictable results. I know I could fix this by just using nconc()
> instead of assignments, but the resulting order of the commands would
> not be exactly what one could expect.
>
> --
> Fernando Nasser
> Red Hat Canada Ltd. E-Mail: fnasser(at)redhat(dot)com
> 2323 Yonge Street, Suite #300
> Toronto, Ontario M4P 2C9

> Index: src/backend/parser/analyze.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/backend/parser/analyze.c,v
> retrieving revision 1.213
> diff -c -p -r1.213 analyze.c
> *** src/backend/parser/analyze.c 2002/01/03 23:21:31 1.213
> --- src/backend/parser/analyze.c 2002/02/12 15:35:58
> *************** typedef struct
> *** 64,80 ****
> } CreateStmtContext;
>
>
> ! static Query *transformStmt(ParseState *pstate, Node *stmt);
> static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
> ! static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
> static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
> ! static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
> static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
> static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
> static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
> static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
> ! static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
> ! static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt);
> static void transformColumnDefinition(ParseState *pstate,
> CreateStmtContext *cxt,
> ColumnDef *column);
> --- 64,85 ----
> } CreateStmtContext;
>
>
> ! static Query *transformStmt(ParseState *pstate, Node *stmt,
> ! List **extras_before, List **extras_after);
> static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
> ! static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
> ! List **extras_before, List **extras_after);
> static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
> ! static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt,
> ! List **extras_before, List **extras_after);
> static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
> static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
> static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
> static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
> ! static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
> ! List **extras_before, List **extras_after);
> ! static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
> ! List **extras_before, List **extras_after);
> static void transformColumnDefinition(ParseState *pstate,
> CreateStmtContext *cxt,
> ColumnDef *column);
> *************** static Oid transformFkeyGetColType(Creat
> *** 101,109 ****
> static void release_pstate_resources(ParseState *pstate);
> static FromExpr *makeFromExpr(List *fromlist, Node *quals);
>
> - /* kluge to return extra info from transformCreateStmt() */
> - static List *extras_before;
> - static List *extras_after;
>
>
> /*
> --- 106,111 ----
> *************** parse_analyze(Node *parseTree, ParseStat
> *** 121,137 ****
> List *result = NIL;
> ParseState *pstate = make_parsestate(parentParseState);
> Query *query;
>
> ! extras_before = extras_after = NIL;
> !
> ! query = transformStmt(pstate, parseTree);
> release_pstate_resources(pstate);
>
> while (extras_before != NIL)
> {
> ! result = lappend(result,
> ! transformStmt(pstate, lfirst(extras_before)));
> ! release_pstate_resources(pstate);
> extras_before = lnext(extras_before);
> }
>
> --- 123,138 ----
> List *result = NIL;
> ParseState *pstate = make_parsestate(parentParseState);
> Query *query;
> + /* Lists to return extra commands from transformation */
> + List *extras_before = NIL;
> + List *extras_after = NIL;
>
> ! query = transformStmt(pstate, parseTree, &extras_before, &extras_after);
> release_pstate_resources(pstate);
>
> while (extras_before != NIL)
> {
> ! result = nconc(result, parse_analyze(lfirst(extras_before), pstate));
> extras_before = lnext(extras_before);
> }
>
> *************** parse_analyze(Node *parseTree, ParseStat
> *** 139,147 ****
>
> while (extras_after != NIL)
> {
> ! result = lappend(result,
> ! transformStmt(pstate, lfirst(extras_after)));
> ! release_pstate_resources(pstate);
> extras_after = lnext(extras_after);
> }
>
> --- 140,146 ----
>
> while (extras_after != NIL)
> {
> ! result = nconc(result, parse_analyze(lfirst(extras_after), pstate));
> extras_after = lnext(extras_after);
> }
>
> *************** release_pstate_resources(ParseState *pst
> *** 164,170 ****
> * transform a Parse tree into a Query tree.
> */
> static Query *
> ! transformStmt(ParseState *pstate, Node *parseTree)
> {
> Query *result = NULL;
>
> --- 163,170 ----
> * transform a Parse tree into a Query tree.
> */
> static Query *
> ! transformStmt(ParseState *pstate, Node *parseTree,
> ! List **extras_before, List **extras_after)
> {
> Query *result = NULL;
>
> *************** transformStmt(ParseState *pstate, Node *
> *** 174,180 ****
> * Non-optimizable statements
> */
> case T_CreateStmt:
> ! result = transformCreateStmt(pstate, (CreateStmt *) parseTree);
> break;
>
> case T_IndexStmt:
> --- 174,181 ----
> * Non-optimizable statements
> */
> case T_CreateStmt:
> ! result = transformCreateStmt(pstate, (CreateStmt *) parseTree,
> ! extras_before, extras_after);
> break;
>
> case T_IndexStmt:
> *************** transformStmt(ParseState *pstate, Node *
> *** 182,195 ****
> break;
>
> case T_RuleStmt:
> ! result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
> break;
>
> case T_ViewStmt:
> {
> ViewStmt *n = (ViewStmt *) parseTree;
>
> ! n->query = transformStmt(pstate, (Node *) n->query);
>
> /*
> * If a list of column names was given, run through and
> --- 183,198 ----
> break;
>
> case T_RuleStmt:
> ! result = transformRuleStmt(pstate, (RuleStmt *) parseTree,
> ! extras_before, extras_after);
> break;
>
> case T_ViewStmt:
> {
> ViewStmt *n = (ViewStmt *) parseTree;
>
> ! n->query = transformStmt(pstate, (Node *) n->query,
> ! extras_before, extras_after);
>
> /*
> * If a list of column names was given, run through and
> *************** transformStmt(ParseState *pstate, Node *
> *** 239,258 ****
>
> result = makeNode(Query);
> result->commandType = CMD_UTILITY;
> ! n->query = transformStmt(pstate, (Node *) n->query);
> result->utilityStmt = (Node *) parseTree;
> }
> break;
>
> case T_AlterTableStmt:
> ! result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree);
> break;
>
> /*
> * Optimizable statements
> */
> case T_InsertStmt:
> ! result = transformInsertStmt(pstate, (InsertStmt *) parseTree);
> break;
>
> case T_DeleteStmt:
> --- 242,264 ----
>
> result = makeNode(Query);
> result->commandType = CMD_UTILITY;
> ! n->query = transformStmt(pstate, (Node *) n->query,
> ! extras_before, extras_after);
> result->utilityStmt = (Node *) parseTree;
> }
> break;
>
> case T_AlterTableStmt:
> ! result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree,
> ! extras_before, extras_after);
> break;
>
> /*
> * Optimizable statements
> */
> case T_InsertStmt:
> ! result = transformInsertStmt(pstate, (InsertStmt *) parseTree,
> ! extras_before, extras_after);
> break;
>
> case T_DeleteStmt:
> *************** transformDeleteStmt(ParseState *pstate,
> *** 337,343 ****
> * transform an Insert Statement
> */
> static Query *
> ! transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
> {
> Query *qry = makeNode(Query);
> List *sub_rtable;
> --- 343,350 ----
> * transform an Insert Statement
> */
> static Query *
> ! transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
> ! List **extras_before, List **extras_after)
> {
> Query *qry = makeNode(Query);
> List *sub_rtable;
> *************** transformInsertStmt(ParseState *pstate,
> *** 402,408 ****
> sub_pstate->p_rtable = sub_rtable;
> sub_pstate->p_namespace = sub_namespace;
>
> ! selectQuery = transformStmt(sub_pstate, stmt->selectStmt);
>
> release_pstate_resources(sub_pstate);
> pfree(sub_pstate);
> --- 409,420 ----
> sub_pstate->p_rtable = sub_rtable;
> sub_pstate->p_namespace = sub_namespace;
>
> ! /*
> ! * Note: we are not expecting that extras_before and extras_after
> ! * are going to be used by the transformation of the SELECT statement.
> ! */
> ! selectQuery = transformStmt(sub_pstate, stmt->selectStmt,
> ! extras_before, extras_after);
>
> release_pstate_resources(sub_pstate);
> pfree(sub_pstate);
> *************** CreateIndexName(char *table_name, char *
> *** 658,664 ****
> * - thomas 1997-12-02
> */
> static Query *
> ! transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
> {
> CreateStmtContext cxt;
> Query *q;
> --- 670,677 ----
> * - thomas 1997-12-02
> */
> static Query *
> ! transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
> ! List **extras_before, List **extras_after)
> {
> CreateStmtContext cxt;
> Query *q;
> *************** transformCreateStmt(ParseState *pstate,
> *** 728,735 ****
> q->utilityStmt = (Node *) stmt;
> stmt->tableElts = cxt.columns;
> stmt->constraints = cxt.ckconstraints;
> ! extras_before = cxt.blist;
> ! extras_after = cxt.alist;
>
> return q;
> }
> --- 741,748 ----
> q->utilityStmt = (Node *) stmt;
> stmt->tableElts = cxt.columns;
> stmt->constraints = cxt.ckconstraints;
> ! *extras_before = nconc (*extras_before, cxt.blist);
> ! *extras_after = nconc (cxt.alist, *extras_after);
>
> return q;
> }
> *************** transformIndexStmt(ParseState *pstate, I
> *** 1668,1674 ****
> * trees which is transformed into a list of query trees.
> */
> static Query *
> ! transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
> {
> Query *qry;
> RangeTblEntry *oldrte;
> --- 1681,1688 ----
> * trees which is transformed into a list of query trees.
> */
> static Query *
> ! transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
> ! List **extras_before, List **extras_after)
> {
> Query *qry;
> RangeTblEntry *oldrte;
> *************** transformRuleStmt(ParseState *pstate, Ru
> *** 1797,1803 ****
> addRTEtoQuery(sub_pstate, newrte, false, true);
>
> /* Transform the rule action statement */
> ! top_subqry = transformStmt(sub_pstate, action);
>
> /*
> * We cannot support utility-statement actions (eg NOTIFY)
> --- 1811,1818 ----
> addRTEtoQuery(sub_pstate, newrte, false, true);
>
> /* Transform the rule action statement */
> ! top_subqry = transformStmt(sub_pstate, action,
> ! extras_before, extras_after);
>
> /*
> * We cannot support utility-statement actions (eg NOTIFY)
> *************** transformUpdateStmt(ParseState *pstate,
> *** 2494,2500 ****
> * transform an Alter Table Statement
> */
> static Query *
> ! transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
> {
> CreateStmtContext cxt;
> Query *qry;
> --- 2509,2516 ----
> * transform an Alter Table Statement
> */
> static Query *
> ! transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
> ! List **extras_before, List **extras_after)
> {
> CreateStmtContext cxt;
> Query *qry;
> *************** transformAlterTableStmt(ParseState *psta
> *** 2534,2541 ****
> transformFKConstraints(pstate, &cxt);
>
> ((ColumnDef *) stmt->def)->constraints = cxt.ckconstraints;
> ! extras_before = cxt.blist;
> ! extras_after = cxt.alist;
> break;
>
> case 'C':
> --- 2550,2557 ----
> transformFKConstraints(pstate, &cxt);
>
> ((ColumnDef *) stmt->def)->constraints = cxt.ckconstraints;
> ! *extras_before = nconc(*extras_before, cxt.blist);
> ! *extras_after = nconc(cxt.alist, *extras_after);
> break;
>
> case 'C':
> *************** transformAlterTableStmt(ParseState *psta
> *** 2571,2578 ****
>
> Assert(cxt.columns == NIL);
> stmt->def = (Node *) nconc(cxt.ckconstraints, cxt.fkconstraints);
> ! extras_before = cxt.blist;
> ! extras_after = cxt.alist;
> break;
>
> default:
> --- 2587,2594 ----
>
> Assert(cxt.columns == NIL);
> stmt->def = (Node *) nconc(cxt.ckconstraints, cxt.fkconstraints);
> ! *extras_before = nconc(*extras_before, cxt.blist);
> ! *extras_after = nconc(cxt.alist, *extras_after);
> break;
>
> default:

>
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