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First phase of plan-invalidation project: create a plan cache management
module and teach PREPARE and protocol-level prepared statements to use it. In service of this, rearrange utility-statement processing so that parse analysis does not assume table schemas can't change before execution for utility statements (necessary because we don't attempt to re-acquire locks for utility statements when reusing a stored plan). This requires some refactoring of the ProcessUtility API, but it ends up cleaner anyway, for instance we can get rid of the QueryContext global. Still to do: fix up SPI and related code to use the plan cache; I'm tempted to try to make SQL functions use it too. Also, there are at least some aspects of system state that we want to ensure remain the same during a replan as in the original processing; search_path certainly ought to behave that way for instance, and perhaps there are others.
This commit is contained in:
Tom Lane
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.99 2007/01/05 22:19:27 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.100 2007/03/13 00:33:40 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -24,6 +24,7 @@
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "optimizer/clauses.h"
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#include "parser/analyze.h"
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#include "parser/parse_expr.h"
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#include "parser/parse_relation.h"
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#include "rewrite/rewriteDefine.h"
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@ -258,54 +259,23 @@ checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc)
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*/
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}
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static RuleStmt *
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FormViewRetrieveRule(const RangeVar *view, Query *viewParse, bool replace)
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{
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RuleStmt *rule;
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/*
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* Create a RuleStmt that corresponds to the suitable rewrite rule args
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* for DefineQueryRewrite();
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*/
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rule = makeNode(RuleStmt);
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rule->relation = copyObject((RangeVar *) view);
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rule->rulename = pstrdup(ViewSelectRuleName);
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rule->whereClause = NULL;
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rule->event = CMD_SELECT;
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rule->instead = true;
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rule->actions = list_make1(viewParse);
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rule->replace = replace;
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return rule;
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}
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static void
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DefineViewRules(const RangeVar *view, Query *viewParse, bool replace)
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{
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RuleStmt *retrieve_rule;
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#ifdef NOTYET
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RuleStmt *replace_rule;
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RuleStmt *append_rule;
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RuleStmt *delete_rule;
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#endif
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retrieve_rule = FormViewRetrieveRule(view, viewParse, replace);
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#ifdef NOTYET
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replace_rule = FormViewReplaceRule(view, viewParse);
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append_rule = FormViewAppendRule(view, viewParse);
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delete_rule = FormViewDeleteRule(view, viewParse);
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#endif
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DefineQueryRewrite(retrieve_rule);
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#ifdef NOTYET
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DefineQueryRewrite(replace_rule);
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DefineQueryRewrite(append_rule);
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DefineQueryRewrite(delete_rule);
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#endif
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/*
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* Set up the ON SELECT rule. Since the query has already been through
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* parse analysis, we use DefineQueryRewrite() directly.
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*/
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DefineQueryRewrite(pstrdup(ViewSelectRuleName),
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(RangeVar *) copyObject((RangeVar *) view),
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NULL,
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CMD_SELECT,
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true,
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replace,
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list_make1(viewParse));
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/*
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* Someday: automatic ON INSERT, etc
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*/
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}
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/*---------------------------------------------------------------
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@ -374,34 +344,80 @@ UpdateRangeTableOfViewParse(Oid viewOid, Query *viewParse)
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return viewParse;
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}
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/*-------------------------------------------------------------------
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/*
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* DefineView
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*
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* - takes a "viewname", "parsetree" pair and then
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* 1) construct the "virtual" relation
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* 2) commit the command but NOT the transaction,
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* so that the relation exists
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* before the rules are defined.
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* 2) define the "n" rules specified in the PRS2 paper
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* over the "virtual" relation
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*-------------------------------------------------------------------
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* Execute a CREATE VIEW command.
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*/
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void
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DefineView(RangeVar *view, Query *viewParse, bool replace)
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DefineView(ViewStmt *stmt, const char *queryString)
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{
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List *stmts;
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Query *viewParse;
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Oid viewOid;
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RangeVar *view;
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/*
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* Run parse analysis to convert the raw parse tree to a Query. Note
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* this also acquires sufficient locks on the source table(s).
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*
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* Since parse analysis scribbles on its input, copy the raw parse tree;
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* this ensures we don't corrupt a prepared statement, for example.
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*/
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stmts = parse_analyze((Node *) copyObject(stmt->query),
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queryString, NULL, 0);
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/*
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* The grammar should ensure that the result is a single SELECT Query.
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*/
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if (list_length(stmts) != 1)
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elog(ERROR, "unexpected parse analysis result");
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viewParse = (Query *) linitial(stmts);
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if (!IsA(viewParse, Query) ||
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viewParse->commandType != CMD_SELECT)
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elog(ERROR, "unexpected parse analysis result");
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/*
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* If a list of column names was given, run through and insert these into
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* the actual query tree. - thomas 2000-03-08
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*/
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if (stmt->aliases != NIL)
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{
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ListCell *alist_item = list_head(stmt->aliases);
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ListCell *targetList;
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foreach(targetList, viewParse->targetList)
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{
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TargetEntry *te = (TargetEntry *) lfirst(targetList);
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Assert(IsA(te, TargetEntry));
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/* junk columns don't get aliases */
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if (te->resjunk)
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continue;
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te->resname = pstrdup(strVal(lfirst(alist_item)));
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alist_item = lnext(alist_item);
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if (alist_item == NULL)
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break; /* done assigning aliases */
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}
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if (alist_item != NULL)
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ereport(ERROR,
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(errcode(ERRCODE_SYNTAX_ERROR),
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errmsg("CREATE VIEW specifies more column "
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"names than columns")));
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}
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/*
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* If the user didn't explicitly ask for a temporary view, check whether
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* we need one implicitly.
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*/
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if (!view->istemp)
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view = stmt->view;
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if (!view->istemp && isViewOnTempTable(viewParse))
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{
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view->istemp = isViewOnTempTable(viewParse);
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if (view->istemp)
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ereport(NOTICE,
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(errmsg("view \"%s\" will be a temporary view",
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view->relname)));
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view = copyObject(view); /* don't corrupt original command */
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view->istemp = true;
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ereport(NOTICE,
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(errmsg("view \"%s\" will be a temporary view",
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view->relname)));
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}
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/*
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@ -410,7 +426,8 @@ DefineView(RangeVar *view, Query *viewParse, bool replace)
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* NOTE: if it already exists and replace is false, the xact will be
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* aborted.
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*/
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viewOid = DefineVirtualRelation(view, viewParse->targetList, replace);
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viewOid = DefineVirtualRelation(view, viewParse->targetList,
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stmt->replace);
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/*
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* The relation we have just created is not visible to any other commands
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@ -428,7 +445,7 @@ DefineView(RangeVar *view, Query *viewParse, bool replace)
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/*
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* Now create the rules associated with the view.
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*/
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DefineViewRules(view, viewParse, replace);
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DefineViewRules(view, viewParse, stmt->replace);
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}
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/*
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