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Adopt the position that only locally-defined defaults matter. Any defaults defined in the remote database do not affect insertions performed through a foreign table (unless they are for columns not known to the foreign table). While it'd arguably be more useful to permit remote defaults to be used, making that work in a consistent fashion requires far more work than seems possible for 9.3.
1371 lines
35 KiB
C
1371 lines
35 KiB
C
/*-------------------------------------------------------------------------
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*
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* deparse.c
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* Query deparser for postgres_fdw
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*
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* This file includes functions that examine query WHERE clauses to see
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* whether they're safe to send to the remote server for execution, as
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* well as functions to construct the query text to be sent. The latter
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* functionality is annoyingly duplicative of ruleutils.c, but there are
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* enough special considerations that it seems best to keep this separate.
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* One saving grace is that we only need deparse logic for node types that
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* we consider safe to send.
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*
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* We assume that the remote session's search_path is exactly "pg_catalog",
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* and thus we need schema-qualify all and only names outside pg_catalog.
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*
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* Portions Copyright (c) 2012-2013, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/postgres_fdw/deparse.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "postgres_fdw.h"
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#include "access/heapam.h"
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#include "access/htup_details.h"
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#include "access/sysattr.h"
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#include "access/transam.h"
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#include "catalog/pg_namespace.h"
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#include "catalog/pg_operator.h"
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#include "catalog/pg_proc.h"
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#include "catalog/pg_type.h"
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#include "commands/defrem.h"
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#include "nodes/nodeFuncs.h"
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#include "optimizer/clauses.h"
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#include "optimizer/var.h"
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#include "parser/parsetree.h"
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#include "utils/builtins.h"
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#include "utils/lsyscache.h"
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#include "utils/syscache.h"
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/*
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* Context for foreign_expr_walker's search of an expression tree.
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*/
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typedef struct foreign_expr_cxt
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{
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/* Input values */
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PlannerInfo *root;
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RelOptInfo *foreignrel;
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/* Result values */
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List *param_numbers; /* Param IDs of PARAM_EXTERN Params */
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} foreign_expr_cxt;
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/*
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* Functions to determine whether an expression can be evaluated safely on
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* remote server.
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*/
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static bool is_foreign_expr(PlannerInfo *root, RelOptInfo *baserel,
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Expr *expr, List **param_numbers);
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static bool foreign_expr_walker(Node *node, foreign_expr_cxt *context);
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static bool is_builtin(Oid procid);
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/*
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* Functions to construct string representation of a node tree.
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*/
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static void deparseTargetList(StringInfo buf,
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PlannerInfo *root,
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Index rtindex,
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Relation rel,
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Bitmapset *attrs_used);
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static void deparseReturningList(StringInfo buf, PlannerInfo *root,
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Index rtindex, Relation rel,
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List *returningList);
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static void deparseColumnRef(StringInfo buf, int varno, int varattno,
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PlannerInfo *root);
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static void deparseRelation(StringInfo buf, Relation rel);
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static void deparseStringLiteral(StringInfo buf, const char *val);
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static void deparseExpr(StringInfo buf, Expr *expr, PlannerInfo *root);
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static void deparseVar(StringInfo buf, Var *node, PlannerInfo *root);
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static void deparseConst(StringInfo buf, Const *node, PlannerInfo *root);
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static void deparseParam(StringInfo buf, Param *node, PlannerInfo *root);
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static void deparseArrayRef(StringInfo buf, ArrayRef *node, PlannerInfo *root);
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static void deparseFuncExpr(StringInfo buf, FuncExpr *node, PlannerInfo *root);
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static void deparseOpExpr(StringInfo buf, OpExpr *node, PlannerInfo *root);
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static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
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static void deparseDistinctExpr(StringInfo buf, DistinctExpr *node,
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PlannerInfo *root);
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static void deparseScalarArrayOpExpr(StringInfo buf, ScalarArrayOpExpr *node,
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PlannerInfo *root);
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static void deparseRelabelType(StringInfo buf, RelabelType *node,
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PlannerInfo *root);
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static void deparseBoolExpr(StringInfo buf, BoolExpr *node, PlannerInfo *root);
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static void deparseNullTest(StringInfo buf, NullTest *node, PlannerInfo *root);
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static void deparseArrayExpr(StringInfo buf, ArrayExpr *node,
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PlannerInfo *root);
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/*
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* Examine each restriction clause in baserel's baserestrictinfo list,
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* and classify them into three groups, which are returned as three lists:
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* - remote_conds contains expressions that can be evaluated remotely,
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* and contain no PARAM_EXTERN Params
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* - param_conds contains expressions that can be evaluated remotely,
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* but contain one or more PARAM_EXTERN Params
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* - local_conds contains all expressions that can't be evaluated remotely
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*
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* In addition, the fourth output parameter param_numbers receives an integer
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* list of the param IDs of the PARAM_EXTERN Params used in param_conds.
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*
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* The reason for segregating param_conds is mainly that it's difficult to
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* use such conditions in remote EXPLAIN. We could do it, but unless the
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* planner has been given representative values for all the Params, we'd
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* have to guess at representative values to use in EXPLAIN EXECUTE.
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* So for now we don't include them when doing remote EXPLAIN.
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*/
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void
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classifyConditions(PlannerInfo *root,
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RelOptInfo *baserel,
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List **remote_conds,
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List **param_conds,
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List **local_conds,
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List **param_numbers)
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{
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ListCell *lc;
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*remote_conds = NIL;
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*param_conds = NIL;
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*local_conds = NIL;
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*param_numbers = NIL;
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foreach(lc, baserel->baserestrictinfo)
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{
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RestrictInfo *ri = (RestrictInfo *) lfirst(lc);
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List *cur_param_numbers;
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if (is_foreign_expr(root, baserel, ri->clause, &cur_param_numbers))
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{
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if (cur_param_numbers == NIL)
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*remote_conds = lappend(*remote_conds, ri);
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else
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{
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*param_conds = lappend(*param_conds, ri);
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/* Use list_concat_unique_int to get rid of duplicates */
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*param_numbers = list_concat_unique_int(*param_numbers,
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cur_param_numbers);
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}
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}
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else
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*local_conds = lappend(*local_conds, ri);
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}
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}
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/*
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* Returns true if given expr is safe to evaluate on the foreign server.
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*
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* If result is true, we also return a list of param IDs of PARAM_EXTERN
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* Params appearing in the expr into *param_numbers.
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*/
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static bool
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is_foreign_expr(PlannerInfo *root,
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RelOptInfo *baserel,
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Expr *expr,
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List **param_numbers)
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{
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foreign_expr_cxt context;
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*param_numbers = NIL; /* default result */
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/*
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* Check that the expression consists of nodes that are safe to execute
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* remotely.
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*/
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context.root = root;
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context.foreignrel = baserel;
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context.param_numbers = NIL;
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if (foreign_expr_walker((Node *) expr, &context))
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return false;
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/*
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* An expression which includes any mutable functions can't be sent over
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* because its result is not stable. For example, sending now() remote
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* side could cause confusion from clock offsets. Future versions might
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* be able to make this choice with more granularity. (We check this last
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* because it requires a lot of expensive catalog lookups.)
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*/
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if (contain_mutable_functions((Node *) expr))
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return false;
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/*
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* OK, so return list of param IDs too.
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*/
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*param_numbers = context.param_numbers;
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return true;
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}
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/*
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* Return true if expression includes any node that is not safe to execute
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* remotely. (We use this convention because expression_tree_walker is
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* designed to abort the tree walk as soon as a TRUE result is detected.)
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*/
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static bool
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foreign_expr_walker(Node *node, foreign_expr_cxt *context)
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{
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bool check_type = true;
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if (node == NULL)
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return false;
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switch (nodeTag(node))
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{
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case T_Var:
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{
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/*
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* Var can be used if it is in the foreign table (we shouldn't
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* really see anything else in baserestrict clauses, but let's
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* check anyway).
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*/
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Var *var = (Var *) node;
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if (var->varno != context->foreignrel->relid ||
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var->varlevelsup != 0)
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return true;
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}
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break;
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case T_Const:
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/* OK */
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break;
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case T_Param:
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{
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Param *p = (Param *) node;
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/*
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* Only external parameters can be sent to remote. (XXX This
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* needs to be improved, but at the point where this code
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* runs, we should only see PARAM_EXTERN Params anyway.)
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*/
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if (p->paramkind != PARAM_EXTERN)
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return true;
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/*
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* Report IDs of PARAM_EXTERN Params. We don't bother to
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* eliminate duplicate list elements here; classifyConditions
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* will do that.
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*/
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context->param_numbers = lappend_int(context->param_numbers,
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p->paramid);
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}
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break;
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case T_ArrayRef:
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{
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ArrayRef *ar = (ArrayRef *) node;;
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/* Assignment should not be in restrictions. */
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if (ar->refassgnexpr != NULL)
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return true;
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}
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break;
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case T_FuncExpr:
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{
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/*
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* If function used by the expression is not built-in, it
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* can't be sent to remote because it might have incompatible
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* semantics on remote side.
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*/
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FuncExpr *fe = (FuncExpr *) node;
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if (!is_builtin(fe->funcid))
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return true;
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}
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break;
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case T_OpExpr:
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case T_DistinctExpr: /* struct-equivalent to OpExpr */
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{
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/*
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* Similarly, only built-in operators can be sent to remote.
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* (If the operator is, surely its underlying function is
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* too.)
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*/
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OpExpr *oe = (OpExpr *) node;
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if (!is_builtin(oe->opno))
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return true;
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}
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break;
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case T_ScalarArrayOpExpr:
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{
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/*
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* Again, only built-in operators can be sent to remote.
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*/
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ScalarArrayOpExpr *oe = (ScalarArrayOpExpr *) node;
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if (!is_builtin(oe->opno))
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return true;
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}
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break;
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case T_RelabelType:
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case T_BoolExpr:
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case T_NullTest:
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case T_ArrayExpr:
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/* OK */
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break;
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case T_List:
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/*
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* We need only fall through to let expression_tree_walker scan
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* the list elements --- but don't apply exprType() to the list.
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*/
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check_type = false;
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break;
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default:
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/*
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* If it's anything else, assume it's unsafe. This list can be
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* expanded later, but don't forget to add deparse support below.
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*/
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return true;
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}
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/*
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* If result type of given expression is not built-in, it can't be sent to
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* remote because it might have incompatible semantics on remote side.
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*/
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if (check_type && !is_builtin(exprType(node)))
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return true;
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/* Recurse to examine sub-nodes */
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return expression_tree_walker(node, foreign_expr_walker, context);
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}
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/*
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* Return true if given object is one of PostgreSQL's built-in objects.
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*
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* We use FirstBootstrapObjectId as the cutoff, so that we only consider
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* objects with hand-assigned OIDs to be "built in", not for instance any
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* function or type defined in the information_schema.
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*
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* Our constraints for dealing with types are tighter than they are for
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* functions or operators: we want to accept only types that are in pg_catalog,
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* else format_type might incorrectly fail to schema-qualify their names.
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* (This could be fixed with some changes to format_type, but for now there's
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* no need.) Thus we must exclude information_schema types.
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*
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* XXX there is a problem with this, which is that the set of built-in
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* objects expands over time. Something that is built-in to us might not
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* be known to the remote server, if it's of an older version. But keeping
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* track of that would be a huge exercise.
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*/
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static bool
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is_builtin(Oid oid)
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{
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return (oid < FirstBootstrapObjectId);
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}
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/*
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* Construct a simple SELECT statement that retrieves desired columns
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* of the specified foreign table, and append it to "buf". The output
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* contains just "SELECT ... FROM tablename".
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*/
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void
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deparseSelectSql(StringInfo buf,
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PlannerInfo *root,
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RelOptInfo *baserel,
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Bitmapset *attrs_used)
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{
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RangeTblEntry *rte = planner_rt_fetch(baserel->relid, root);
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Relation rel;
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/*
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* Core code already has some lock on each rel being planned, so we can
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* use NoLock here.
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*/
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rel = heap_open(rte->relid, NoLock);
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/*
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* Construct SELECT list
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*/
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appendStringInfoString(buf, "SELECT ");
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deparseTargetList(buf, root, baserel->relid, rel, attrs_used);
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/*
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* Construct FROM clause
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*/
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appendStringInfoString(buf, " FROM ");
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deparseRelation(buf, rel);
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heap_close(rel, NoLock);
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}
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/*
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* Emit a target list that retrieves the columns specified in attrs_used.
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* This is used for both SELECT and RETURNING targetlists.
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*
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* We list attributes in order of the foreign table's columns, but replace
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* any attributes that need not be fetched with NULL constants. (We can't
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* just omit such attributes, or we'll lose track of which columns are
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* which at runtime.) Note however that any dropped columns are ignored.
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* Also, if ctid needs to be retrieved, it's added at the end.
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*/
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static void
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deparseTargetList(StringInfo buf,
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PlannerInfo *root,
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Index rtindex,
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Relation rel,
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Bitmapset *attrs_used)
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{
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TupleDesc tupdesc = RelationGetDescr(rel);
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bool have_wholerow;
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bool first;
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int i;
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/* If there's a whole-row reference, we'll need all the columns. */
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have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
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attrs_used);
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first = true;
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for (i = 1; i <= tupdesc->natts; i++)
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{
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Form_pg_attribute attr = tupdesc->attrs[i - 1];
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/* Ignore dropped attributes. */
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if (attr->attisdropped)
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continue;
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if (!first)
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appendStringInfoString(buf, ", ");
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first = false;
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if (have_wholerow ||
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bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
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attrs_used))
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deparseColumnRef(buf, rtindex, i, root);
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else
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appendStringInfoString(buf, "NULL");
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}
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/*
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* Add ctid if needed. We currently don't support retrieving any other
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* system columns.
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*/
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if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber,
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attrs_used))
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{
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if (!first)
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appendStringInfoString(buf, ", ");
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first = false;
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appendStringInfoString(buf, "ctid");
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}
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/* Don't generate bad syntax if no undropped columns */
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if (first)
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appendStringInfoString(buf, "NULL");
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}
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/*
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* Deparse WHERE clauses in given list of RestrictInfos and append them to buf.
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*
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* If no WHERE clause already exists in the buffer, is_first should be true.
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*/
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void
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appendWhereClause(StringInfo buf,
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PlannerInfo *root,
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List *exprs,
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bool is_first)
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{
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int nestlevel;
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ListCell *lc;
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/* Make sure any constants in the exprs are printed portably */
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nestlevel = set_transmission_modes();
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foreach(lc, exprs)
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{
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RestrictInfo *ri = (RestrictInfo *) lfirst(lc);
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/* Connect expressions with "AND" and parenthesize each condition. */
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if (is_first)
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appendStringInfoString(buf, " WHERE ");
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else
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appendStringInfoString(buf, " AND ");
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appendStringInfoChar(buf, '(');
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deparseExpr(buf, ri->clause, root);
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appendStringInfoChar(buf, ')');
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is_first = false;
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}
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reset_transmission_modes(nestlevel);
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}
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/*
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* deparse remote INSERT statement
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*/
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void
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deparseInsertSql(StringInfo buf, PlannerInfo *root,
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Index rtindex, Relation rel,
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List *targetAttrs, List *returningList)
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{
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AttrNumber pindex;
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bool first;
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ListCell *lc;
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appendStringInfoString(buf, "INSERT INTO ");
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deparseRelation(buf, rel);
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if (targetAttrs)
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{
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appendStringInfoString(buf, "(");
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first = true;
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foreach(lc, targetAttrs)
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{
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int attnum = lfirst_int(lc);
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if (!first)
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appendStringInfoString(buf, ", ");
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first = false;
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deparseColumnRef(buf, rtindex, attnum, root);
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}
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appendStringInfoString(buf, ") VALUES (");
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pindex = 1;
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first = true;
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foreach(lc, targetAttrs)
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{
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if (!first)
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appendStringInfoString(buf, ", ");
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first = false;
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appendStringInfo(buf, "$%d", pindex);
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pindex++;
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}
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|
|
appendStringInfoString(buf, ")");
|
|
}
|
|
else
|
|
appendStringInfoString(buf, " DEFAULT VALUES");
|
|
|
|
if (returningList)
|
|
deparseReturningList(buf, root, rtindex, rel, returningList);
|
|
}
|
|
|
|
/*
|
|
* deparse remote UPDATE statement
|
|
*/
|
|
void
|
|
deparseUpdateSql(StringInfo buf, PlannerInfo *root,
|
|
Index rtindex, Relation rel,
|
|
List *targetAttrs, List *returningList)
|
|
{
|
|
AttrNumber pindex;
|
|
bool first;
|
|
ListCell *lc;
|
|
|
|
appendStringInfoString(buf, "UPDATE ");
|
|
deparseRelation(buf, rel);
|
|
appendStringInfoString(buf, " SET ");
|
|
|
|
pindex = 2; /* ctid is always the first param */
|
|
first = true;
|
|
foreach(lc, targetAttrs)
|
|
{
|
|
int attnum = lfirst_int(lc);
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
deparseColumnRef(buf, rtindex, attnum, root);
|
|
appendStringInfo(buf, " = $%d", pindex);
|
|
pindex++;
|
|
}
|
|
appendStringInfoString(buf, " WHERE ctid = $1");
|
|
|
|
if (returningList)
|
|
deparseReturningList(buf, root, rtindex, rel, returningList);
|
|
}
|
|
|
|
/*
|
|
* deparse remote DELETE statement
|
|
*/
|
|
void
|
|
deparseDeleteSql(StringInfo buf, PlannerInfo *root,
|
|
Index rtindex, Relation rel,
|
|
List *returningList)
|
|
{
|
|
appendStringInfoString(buf, "DELETE FROM ");
|
|
deparseRelation(buf, rel);
|
|
appendStringInfoString(buf, " WHERE ctid = $1");
|
|
|
|
if (returningList)
|
|
deparseReturningList(buf, root, rtindex, rel, returningList);
|
|
}
|
|
|
|
/*
|
|
* deparse RETURNING clause of INSERT/UPDATE/DELETE
|
|
*/
|
|
static void
|
|
deparseReturningList(StringInfo buf, PlannerInfo *root,
|
|
Index rtindex, Relation rel,
|
|
List *returningList)
|
|
{
|
|
Bitmapset *attrs_used;
|
|
|
|
/*
|
|
* We need the attrs mentioned in the query's RETURNING list.
|
|
*/
|
|
attrs_used = NULL;
|
|
pull_varattnos((Node *) returningList, rtindex,
|
|
&attrs_used);
|
|
|
|
appendStringInfoString(buf, " RETURNING ");
|
|
deparseTargetList(buf, root, rtindex, rel, attrs_used);
|
|
}
|
|
|
|
/*
|
|
* Construct SELECT statement to acquire size in blocks of given relation.
|
|
*
|
|
* Note: we use local definition of block size, not remote definition.
|
|
* This is perhaps debatable.
|
|
*
|
|
* Note: pg_relation_size() exists in 8.1 and later.
|
|
*/
|
|
void
|
|
deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
|
|
{
|
|
StringInfoData relname;
|
|
|
|
/* We'll need the remote relation name as a literal. */
|
|
initStringInfo(&relname);
|
|
deparseRelation(&relname, rel);
|
|
|
|
appendStringInfo(buf, "SELECT pg_catalog.pg_relation_size(");
|
|
deparseStringLiteral(buf, relname.data);
|
|
appendStringInfo(buf, "::pg_catalog.regclass) / %d", BLCKSZ);
|
|
}
|
|
|
|
/*
|
|
* Construct SELECT statement to acquire sample rows of given relation.
|
|
*
|
|
* Note: command is appended to whatever might be in buf already.
|
|
*/
|
|
void
|
|
deparseAnalyzeSql(StringInfo buf, Relation rel)
|
|
{
|
|
Oid relid = RelationGetRelid(rel);
|
|
TupleDesc tupdesc = RelationGetDescr(rel);
|
|
int i;
|
|
char *colname;
|
|
List *options;
|
|
ListCell *lc;
|
|
bool first = true;
|
|
|
|
appendStringInfoString(buf, "SELECT ");
|
|
for (i = 0; i < tupdesc->natts; i++)
|
|
{
|
|
/* Ignore dropped columns. */
|
|
if (tupdesc->attrs[i]->attisdropped)
|
|
continue;
|
|
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
first = false;
|
|
|
|
/* Use attribute name or column_name option. */
|
|
colname = NameStr(tupdesc->attrs[i]->attname);
|
|
options = GetForeignColumnOptions(relid, i + 1);
|
|
|
|
foreach(lc, options)
|
|
{
|
|
DefElem *def = (DefElem *) lfirst(lc);
|
|
|
|
if (strcmp(def->defname, "column_name") == 0)
|
|
{
|
|
colname = defGetString(def);
|
|
break;
|
|
}
|
|
}
|
|
|
|
appendStringInfoString(buf, quote_identifier(colname));
|
|
}
|
|
|
|
/* Don't generate bad syntax for zero-column relation. */
|
|
if (first)
|
|
appendStringInfoString(buf, "NULL");
|
|
|
|
/*
|
|
* Construct FROM clause
|
|
*/
|
|
appendStringInfoString(buf, " FROM ");
|
|
deparseRelation(buf, rel);
|
|
}
|
|
|
|
/*
|
|
* Construct name to use for given column, and emit it into buf.
|
|
* If it has a column_name FDW option, use that instead of attribute name.
|
|
*/
|
|
static void
|
|
deparseColumnRef(StringInfo buf, int varno, int varattno, PlannerInfo *root)
|
|
{
|
|
RangeTblEntry *rte;
|
|
char *colname = NULL;
|
|
List *options;
|
|
ListCell *lc;
|
|
|
|
/* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
|
|
Assert(!IS_SPECIAL_VARNO(varno));
|
|
|
|
/* Get RangeTblEntry from array in PlannerInfo. */
|
|
rte = planner_rt_fetch(varno, root);
|
|
|
|
/*
|
|
* If it's a column of a foreign table, and it has the column_name FDW
|
|
* option, use that value.
|
|
*/
|
|
options = GetForeignColumnOptions(rte->relid, varattno);
|
|
foreach(lc, options)
|
|
{
|
|
DefElem *def = (DefElem *) lfirst(lc);
|
|
|
|
if (strcmp(def->defname, "column_name") == 0)
|
|
{
|
|
colname = defGetString(def);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If it's a column of a regular table or it doesn't have column_name FDW
|
|
* option, use attribute name.
|
|
*/
|
|
if (colname == NULL)
|
|
colname = get_relid_attribute_name(rte->relid, varattno);
|
|
|
|
appendStringInfoString(buf, quote_identifier(colname));
|
|
}
|
|
|
|
/*
|
|
* Append remote name of specified foreign table to buf.
|
|
* Use value of table_name FDW option (if any) instead of relation's name.
|
|
* Similarly, schema_name FDW option overrides schema name.
|
|
*/
|
|
static void
|
|
deparseRelation(StringInfo buf, Relation rel)
|
|
{
|
|
ForeignTable *table;
|
|
const char *nspname = NULL;
|
|
const char *relname = NULL;
|
|
ListCell *lc;
|
|
|
|
/* obtain additional catalog information. */
|
|
table = GetForeignTable(RelationGetRelid(rel));
|
|
|
|
/*
|
|
* Use value of FDW options if any, instead of the name of object itself.
|
|
*/
|
|
foreach(lc, table->options)
|
|
{
|
|
DefElem *def = (DefElem *) lfirst(lc);
|
|
|
|
if (strcmp(def->defname, "schema_name") == 0)
|
|
nspname = defGetString(def);
|
|
else if (strcmp(def->defname, "table_name") == 0)
|
|
relname = defGetString(def);
|
|
}
|
|
|
|
/*
|
|
* Note: we could skip printing the schema name if it's pg_catalog, but
|
|
* that doesn't seem worth the trouble.
|
|
*/
|
|
if (nspname == NULL)
|
|
nspname = get_namespace_name(RelationGetNamespace(rel));
|
|
if (relname == NULL)
|
|
relname = RelationGetRelationName(rel);
|
|
|
|
appendStringInfo(buf, "%s.%s",
|
|
quote_identifier(nspname), quote_identifier(relname));
|
|
}
|
|
|
|
/*
|
|
* Append a SQL string literal representing "val" to buf.
|
|
*/
|
|
static void
|
|
deparseStringLiteral(StringInfo buf, const char *val)
|
|
{
|
|
const char *valptr;
|
|
|
|
/*
|
|
* Rather than making assumptions about the remote server's value of
|
|
* standard_conforming_strings, always use E'foo' syntax if there are any
|
|
* backslashes. This will fail on remote servers before 8.1, but those
|
|
* are long out of support.
|
|
*/
|
|
if (strchr(val, '\\') != NULL)
|
|
appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
|
|
appendStringInfoChar(buf, '\'');
|
|
for (valptr = val; *valptr; valptr++)
|
|
{
|
|
char ch = *valptr;
|
|
|
|
if (SQL_STR_DOUBLE(ch, true))
|
|
appendStringInfoChar(buf, ch);
|
|
appendStringInfoChar(buf, ch);
|
|
}
|
|
appendStringInfoChar(buf, '\'');
|
|
}
|
|
|
|
/*
|
|
* Deparse given expression into buf.
|
|
*
|
|
* This function must support all the same node types that foreign_expr_walker
|
|
* accepts.
|
|
*
|
|
* Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
|
|
* scheme: anything more complex than a Var, Const, function call or cast
|
|
* should be self-parenthesized.
|
|
*/
|
|
static void
|
|
deparseExpr(StringInfo buf, Expr *node, PlannerInfo *root)
|
|
{
|
|
if (node == NULL)
|
|
return;
|
|
|
|
switch (nodeTag(node))
|
|
{
|
|
case T_Var:
|
|
deparseVar(buf, (Var *) node, root);
|
|
break;
|
|
case T_Const:
|
|
deparseConst(buf, (Const *) node, root);
|
|
break;
|
|
case T_Param:
|
|
deparseParam(buf, (Param *) node, root);
|
|
break;
|
|
case T_ArrayRef:
|
|
deparseArrayRef(buf, (ArrayRef *) node, root);
|
|
break;
|
|
case T_FuncExpr:
|
|
deparseFuncExpr(buf, (FuncExpr *) node, root);
|
|
break;
|
|
case T_OpExpr:
|
|
deparseOpExpr(buf, (OpExpr *) node, root);
|
|
break;
|
|
case T_DistinctExpr:
|
|
deparseDistinctExpr(buf, (DistinctExpr *) node, root);
|
|
break;
|
|
case T_ScalarArrayOpExpr:
|
|
deparseScalarArrayOpExpr(buf, (ScalarArrayOpExpr *) node, root);
|
|
break;
|
|
case T_RelabelType:
|
|
deparseRelabelType(buf, (RelabelType *) node, root);
|
|
break;
|
|
case T_BoolExpr:
|
|
deparseBoolExpr(buf, (BoolExpr *) node, root);
|
|
break;
|
|
case T_NullTest:
|
|
deparseNullTest(buf, (NullTest *) node, root);
|
|
break;
|
|
case T_ArrayExpr:
|
|
deparseArrayExpr(buf, (ArrayExpr *) node, root);
|
|
break;
|
|
default:
|
|
elog(ERROR, "unsupported expression type for deparse: %d",
|
|
(int) nodeTag(node));
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse given Var node into buf.
|
|
*/
|
|
static void
|
|
deparseVar(StringInfo buf, Var *node, PlannerInfo *root)
|
|
{
|
|
Assert(node->varlevelsup == 0);
|
|
deparseColumnRef(buf, node->varno, node->varattno, root);
|
|
}
|
|
|
|
/*
|
|
* Deparse given constant value into buf.
|
|
*
|
|
* This function has to be kept in sync with ruleutils.c's get_const_expr.
|
|
*/
|
|
static void
|
|
deparseConst(StringInfo buf, Const *node, PlannerInfo *root)
|
|
{
|
|
Oid typoutput;
|
|
bool typIsVarlena;
|
|
char *extval;
|
|
bool isfloat = false;
|
|
bool needlabel;
|
|
|
|
if (node->constisnull)
|
|
{
|
|
appendStringInfo(buf, "NULL");
|
|
appendStringInfo(buf, "::%s",
|
|
format_type_with_typemod(node->consttype,
|
|
node->consttypmod));
|
|
return;
|
|
}
|
|
|
|
getTypeOutputInfo(node->consttype,
|
|
&typoutput, &typIsVarlena);
|
|
extval = OidOutputFunctionCall(typoutput, node->constvalue);
|
|
|
|
switch (node->consttype)
|
|
{
|
|
case INT2OID:
|
|
case INT4OID:
|
|
case INT8OID:
|
|
case OIDOID:
|
|
case FLOAT4OID:
|
|
case FLOAT8OID:
|
|
case NUMERICOID:
|
|
{
|
|
/*
|
|
* No need to quote unless it's a special value such as 'NaN'.
|
|
* See comments in get_const_expr().
|
|
*/
|
|
if (strspn(extval, "0123456789+-eE.") == strlen(extval))
|
|
{
|
|
if (extval[0] == '+' || extval[0] == '-')
|
|
appendStringInfo(buf, "(%s)", extval);
|
|
else
|
|
appendStringInfoString(buf, extval);
|
|
if (strcspn(extval, "eE.") != strlen(extval))
|
|
isfloat = true; /* it looks like a float */
|
|
}
|
|
else
|
|
appendStringInfo(buf, "'%s'", extval);
|
|
}
|
|
break;
|
|
case BITOID:
|
|
case VARBITOID:
|
|
appendStringInfo(buf, "B'%s'", extval);
|
|
break;
|
|
case BOOLOID:
|
|
if (strcmp(extval, "t") == 0)
|
|
appendStringInfoString(buf, "true");
|
|
else
|
|
appendStringInfoString(buf, "false");
|
|
break;
|
|
default:
|
|
deparseStringLiteral(buf, extval);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Append ::typename unless the constant will be implicitly typed as the
|
|
* right type when it is read in.
|
|
*
|
|
* XXX this code has to be kept in sync with the behavior of the parser,
|
|
* especially make_const.
|
|
*/
|
|
switch (node->consttype)
|
|
{
|
|
case BOOLOID:
|
|
case INT4OID:
|
|
case UNKNOWNOID:
|
|
needlabel = false;
|
|
break;
|
|
case NUMERICOID:
|
|
needlabel = !isfloat || (node->consttypmod >= 0);
|
|
break;
|
|
default:
|
|
needlabel = true;
|
|
break;
|
|
}
|
|
if (needlabel)
|
|
appendStringInfo(buf, "::%s",
|
|
format_type_with_typemod(node->consttype,
|
|
node->consttypmod));
|
|
}
|
|
|
|
/*
|
|
* Deparse given Param node into buf.
|
|
*
|
|
* We don't need to renumber the parameter ID, because the executor functions
|
|
* in postgres_fdw.c preserve the numbering of PARAM_EXTERN Params.
|
|
* (This might change soon.)
|
|
*
|
|
* Note: we label the Param's type explicitly rather than relying on
|
|
* transmitting a numeric type OID in PQexecParams(). This allows us to
|
|
* avoid assuming that types have the same OIDs on the remote side as they
|
|
* do locally --- they need only have the same names.
|
|
*/
|
|
static void
|
|
deparseParam(StringInfo buf, Param *node, PlannerInfo *root)
|
|
{
|
|
Assert(node->paramkind == PARAM_EXTERN);
|
|
appendStringInfo(buf, "$%d", node->paramid);
|
|
appendStringInfo(buf, "::%s",
|
|
format_type_with_typemod(node->paramtype,
|
|
node->paramtypmod));
|
|
}
|
|
|
|
/*
|
|
* Deparse an array subscript expression.
|
|
*/
|
|
static void
|
|
deparseArrayRef(StringInfo buf, ArrayRef *node, PlannerInfo *root)
|
|
{
|
|
ListCell *lowlist_item;
|
|
ListCell *uplist_item;
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/*
|
|
* Deparse referenced array expression first. If that expression includes
|
|
* a cast, we have to parenthesize to prevent the array subscript from
|
|
* being taken as typename decoration. We can avoid that in the typical
|
|
* case of subscripting a Var, but otherwise do it.
|
|
*/
|
|
if (IsA(node->refexpr, Var))
|
|
deparseExpr(buf, node->refexpr, root);
|
|
else
|
|
{
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(buf, node->refexpr, root);
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/* Deparse subscript expressions. */
|
|
lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
|
|
foreach(uplist_item, node->refupperindexpr)
|
|
{
|
|
appendStringInfoChar(buf, '[');
|
|
if (lowlist_item)
|
|
{
|
|
deparseExpr(buf, lfirst(lowlist_item), root);
|
|
appendStringInfoChar(buf, ':');
|
|
lowlist_item = lnext(lowlist_item);
|
|
}
|
|
deparseExpr(buf, lfirst(uplist_item), root);
|
|
appendStringInfoChar(buf, ']');
|
|
}
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse given node which represents a function call into buf.
|
|
*/
|
|
static void
|
|
deparseFuncExpr(StringInfo buf, FuncExpr *node, PlannerInfo *root)
|
|
{
|
|
HeapTuple proctup;
|
|
Form_pg_proc procform;
|
|
const char *proname;
|
|
bool use_variadic;
|
|
bool first;
|
|
ListCell *arg;
|
|
|
|
/*
|
|
* If the function call came from an implicit coercion, then just show the
|
|
* first argument.
|
|
*/
|
|
if (node->funcformat == COERCE_IMPLICIT_CAST)
|
|
{
|
|
deparseExpr(buf, (Expr *) linitial(node->args), root);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If the function call came from a cast, then show the first argument
|
|
* plus an explicit cast operation.
|
|
*/
|
|
if (node->funcformat == COERCE_EXPLICIT_CAST)
|
|
{
|
|
Oid rettype = node->funcresulttype;
|
|
int32 coercedTypmod;
|
|
|
|
/* Get the typmod if this is a length-coercion function */
|
|
(void) exprIsLengthCoercion((Node *) node, &coercedTypmod);
|
|
|
|
deparseExpr(buf, (Expr *) linitial(node->args), root);
|
|
appendStringInfo(buf, "::%s",
|
|
format_type_with_typemod(rettype, coercedTypmod));
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Normal function: display as proname(args).
|
|
*/
|
|
proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(node->funcid));
|
|
if (!HeapTupleIsValid(proctup))
|
|
elog(ERROR, "cache lookup failed for function %u", node->funcid);
|
|
procform = (Form_pg_proc) GETSTRUCT(proctup);
|
|
|
|
/* Check if need to print VARIADIC (cf. ruleutils.c) */
|
|
if (OidIsValid(procform->provariadic))
|
|
{
|
|
if (procform->provariadic != ANYOID)
|
|
use_variadic = true;
|
|
else
|
|
use_variadic = node->funcvariadic;
|
|
}
|
|
else
|
|
use_variadic = false;
|
|
|
|
/* Print schema name only if it's not pg_catalog */
|
|
if (procform->pronamespace != PG_CATALOG_NAMESPACE)
|
|
{
|
|
const char *schemaname;
|
|
|
|
schemaname = get_namespace_name(procform->pronamespace);
|
|
appendStringInfo(buf, "%s.", quote_identifier(schemaname));
|
|
}
|
|
|
|
/* Deparse the function name ... */
|
|
proname = NameStr(procform->proname);
|
|
appendStringInfo(buf, "%s(", quote_identifier(proname));
|
|
/* ... and all the arguments */
|
|
first = true;
|
|
foreach(arg, node->args)
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
if (use_variadic && lnext(arg) == NULL)
|
|
appendStringInfoString(buf, "VARIADIC ");
|
|
deparseExpr(buf, (Expr *) lfirst(arg), root);
|
|
first = false;
|
|
}
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
ReleaseSysCache(proctup);
|
|
}
|
|
|
|
/*
|
|
* Deparse given operator expression into buf. To avoid problems around
|
|
* priority of operations, we always parenthesize the arguments.
|
|
*/
|
|
static void
|
|
deparseOpExpr(StringInfo buf, OpExpr *node, PlannerInfo *root)
|
|
{
|
|
HeapTuple tuple;
|
|
Form_pg_operator form;
|
|
char oprkind;
|
|
ListCell *arg;
|
|
|
|
/* Retrieve information about the operator from system catalog. */
|
|
tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
|
|
if (!HeapTupleIsValid(tuple))
|
|
elog(ERROR, "cache lookup failed for operator %u", node->opno);
|
|
form = (Form_pg_operator) GETSTRUCT(tuple);
|
|
oprkind = form->oprkind;
|
|
|
|
/* Sanity check. */
|
|
Assert((oprkind == 'r' && list_length(node->args) == 1) ||
|
|
(oprkind == 'l' && list_length(node->args) == 1) ||
|
|
(oprkind == 'b' && list_length(node->args) == 2));
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/* Deparse left operand. */
|
|
if (oprkind == 'r' || oprkind == 'b')
|
|
{
|
|
arg = list_head(node->args);
|
|
deparseExpr(buf, lfirst(arg), root);
|
|
appendStringInfoChar(buf, ' ');
|
|
}
|
|
|
|
/* Deparse operator name. */
|
|
deparseOperatorName(buf, form);
|
|
|
|
/* Deparse right operand. */
|
|
if (oprkind == 'l' || oprkind == 'b')
|
|
{
|
|
arg = list_tail(node->args);
|
|
appendStringInfoChar(buf, ' ');
|
|
deparseExpr(buf, lfirst(arg), root);
|
|
}
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
ReleaseSysCache(tuple);
|
|
}
|
|
|
|
/*
|
|
* Print the name of an operator.
|
|
*/
|
|
static void
|
|
deparseOperatorName(StringInfo buf, Form_pg_operator opform)
|
|
{
|
|
char *opname;
|
|
|
|
/* opname is not a SQL identifier, so we should not quote it. */
|
|
opname = NameStr(opform->oprname);
|
|
|
|
/* Print schema name only if it's not pg_catalog */
|
|
if (opform->oprnamespace != PG_CATALOG_NAMESPACE)
|
|
{
|
|
const char *opnspname;
|
|
|
|
opnspname = get_namespace_name(opform->oprnamespace);
|
|
/* Print fully qualified operator name. */
|
|
appendStringInfo(buf, "OPERATOR(%s.%s)",
|
|
quote_identifier(opnspname), opname);
|
|
}
|
|
else
|
|
{
|
|
/* Just print operator name. */
|
|
appendStringInfo(buf, "%s", opname);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Deparse IS DISTINCT FROM.
|
|
*/
|
|
static void
|
|
deparseDistinctExpr(StringInfo buf, DistinctExpr *node, PlannerInfo *root)
|
|
{
|
|
Assert(list_length(node->args) == 2);
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(buf, linitial(node->args), root);
|
|
appendStringInfoString(buf, " IS DISTINCT FROM ");
|
|
deparseExpr(buf, lsecond(node->args), root);
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse given ScalarArrayOpExpr expression into buf. To avoid problems
|
|
* around priority of operations, we always parenthesize the arguments.
|
|
*/
|
|
static void
|
|
deparseScalarArrayOpExpr(StringInfo buf,
|
|
ScalarArrayOpExpr *node,
|
|
PlannerInfo *root)
|
|
{
|
|
HeapTuple tuple;
|
|
Form_pg_operator form;
|
|
Expr *arg1;
|
|
Expr *arg2;
|
|
|
|
/* Retrieve information about the operator from system catalog. */
|
|
tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
|
|
if (!HeapTupleIsValid(tuple))
|
|
elog(ERROR, "cache lookup failed for operator %u", node->opno);
|
|
form = (Form_pg_operator) GETSTRUCT(tuple);
|
|
|
|
/* Sanity check. */
|
|
Assert(list_length(node->args) == 2);
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, '(');
|
|
|
|
/* Deparse left operand. */
|
|
arg1 = linitial(node->args);
|
|
deparseExpr(buf, arg1, root);
|
|
appendStringInfoChar(buf, ' ');
|
|
|
|
/* Deparse operator name plus decoration. */
|
|
deparseOperatorName(buf, form);
|
|
appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
|
|
|
|
/* Deparse right operand. */
|
|
arg2 = lsecond(node->args);
|
|
deparseExpr(buf, arg2, root);
|
|
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
/* Always parenthesize the expression. */
|
|
appendStringInfoChar(buf, ')');
|
|
|
|
ReleaseSysCache(tuple);
|
|
}
|
|
|
|
/*
|
|
* Deparse a RelabelType (binary-compatible cast) node.
|
|
*/
|
|
static void
|
|
deparseRelabelType(StringInfo buf, RelabelType *node, PlannerInfo *root)
|
|
{
|
|
deparseExpr(buf, node->arg, root);
|
|
if (node->relabelformat != COERCE_IMPLICIT_CAST)
|
|
appendStringInfo(buf, "::%s",
|
|
format_type_with_typemod(node->resulttype,
|
|
node->resulttypmod));
|
|
}
|
|
|
|
/*
|
|
* Deparse a BoolExpr node.
|
|
*
|
|
* Note: by the time we get here, AND and OR expressions have been flattened
|
|
* into N-argument form, so we'd better be prepared to deal with that.
|
|
*/
|
|
static void
|
|
deparseBoolExpr(StringInfo buf, BoolExpr *node, PlannerInfo *root)
|
|
{
|
|
const char *op = NULL; /* keep compiler quiet */
|
|
bool first;
|
|
ListCell *lc;
|
|
|
|
switch (node->boolop)
|
|
{
|
|
case AND_EXPR:
|
|
op = "AND";
|
|
break;
|
|
case OR_EXPR:
|
|
op = "OR";
|
|
break;
|
|
case NOT_EXPR:
|
|
appendStringInfoString(buf, "(NOT ");
|
|
deparseExpr(buf, linitial(node->args), root);
|
|
appendStringInfoChar(buf, ')');
|
|
return;
|
|
}
|
|
|
|
appendStringInfoChar(buf, '(');
|
|
first = true;
|
|
foreach(lc, node->args)
|
|
{
|
|
if (!first)
|
|
appendStringInfo(buf, " %s ", op);
|
|
deparseExpr(buf, (Expr *) lfirst(lc), root);
|
|
first = false;
|
|
}
|
|
appendStringInfoChar(buf, ')');
|
|
}
|
|
|
|
/*
|
|
* Deparse IS [NOT] NULL expression.
|
|
*/
|
|
static void
|
|
deparseNullTest(StringInfo buf, NullTest *node, PlannerInfo *root)
|
|
{
|
|
appendStringInfoChar(buf, '(');
|
|
deparseExpr(buf, node->arg, root);
|
|
if (node->nulltesttype == IS_NULL)
|
|
appendStringInfoString(buf, " IS NULL)");
|
|
else
|
|
appendStringInfoString(buf, " IS NOT NULL)");
|
|
}
|
|
|
|
/*
|
|
* Deparse ARRAY[...] construct.
|
|
*/
|
|
static void
|
|
deparseArrayExpr(StringInfo buf, ArrayExpr *node, PlannerInfo *root)
|
|
{
|
|
bool first = true;
|
|
ListCell *lc;
|
|
|
|
appendStringInfoString(buf, "ARRAY[");
|
|
foreach(lc, node->elements)
|
|
{
|
|
if (!first)
|
|
appendStringInfoString(buf, ", ");
|
|
deparseExpr(buf, lfirst(lc), root);
|
|
first = false;
|
|
}
|
|
appendStringInfoChar(buf, ']');
|
|
|
|
/* If the array is empty, we need an explicit cast to the array type. */
|
|
if (node->elements == NIL)
|
|
appendStringInfo(buf, "::%s",
|
|
format_type_with_typemod(node->array_typeid, -1));
|
|
}
|