@ -104,7 +104,9 @@ typedef struct
* the current context ' s namespaces list .
*
* The rangetable is the list of actual RTEs from the query tree , and the
* cte list is the list of actual CTEs .
* cte list is the list of actual CTEs . rtable_names holds the alias name
* to be used for each RTE ( either a C string , or NULL for nameless RTEs
* such as unnamed joins ) .
*
* When deparsing plan trees , there is always just a single item in the
* deparse_namespace list ( since a plan tree never contains Vars with
@ -119,6 +121,7 @@ typedef struct
typedef struct
{
List * rtable ; /* List of RangeTblEntry nodes */
List * rtable_names ; /* Parallel list of names for RTEs */
List * ctes ; /* List of CommonTableExpr nodes */
/* Remaining fields are used only when deparsing a Plan tree: */
PlanState * planstate ; /* immediate parent of current expression */
@ -172,6 +175,11 @@ static text *pg_get_expr_worker(text *expr, Oid relid, const char *relname,
static int print_function_arguments ( StringInfo buf , HeapTuple proctup ,
bool print_table_args , bool print_defaults ) ;
static void print_function_rettype ( StringInfo buf , HeapTuple proctup ) ;
static void set_rtable_names ( deparse_namespace * dpns , List * parent_namespaces ,
Bitmapset * rels_used ) ;
static bool refname_is_unique ( char * refname , deparse_namespace * dpns ,
List * parent_namespaces ) ;
static char * get_rtable_name ( int rtindex , deparse_context * context ) ;
static void set_deparse_planstate ( deparse_namespace * dpns , PlanState * ps ) ;
static void push_child_plan ( deparse_namespace * dpns , PlanState * ps ,
deparse_namespace * save_dpns ) ;
@ -212,8 +220,6 @@ static void get_rule_windowspec(WindowClause *wc, List *targetList,
deparse_context * context ) ;
static char * get_variable ( Var * var , int levelsup , bool istoplevel ,
deparse_context * context ) ;
static RangeTblEntry * find_rte_by_refname ( const char * refname ,
deparse_context * context ) ;
static Node * find_param_referent ( Param * param , deparse_context * context ,
deparse_namespace * * dpns_p , ListCell * * ancestor_cell_p ) ;
static void get_parameter ( Param * param , deparse_context * context ) ;
@ -676,7 +682,8 @@ pg_get_triggerdef_worker(Oid trigid, bool pretty)
oldrte - > rtekind = RTE_RELATION ;
oldrte - > relid = trigrec - > tgrelid ;
oldrte - > relkind = relkind ;
oldrte - > eref = makeAlias ( " old " , NIL ) ;
oldrte - > alias = makeAlias ( " old " , NIL ) ;
oldrte - > eref = oldrte - > alias ;
oldrte - > lateral = false ;
oldrte - > inh = false ;
oldrte - > inFromCl = true ;
@ -685,7 +692,8 @@ pg_get_triggerdef_worker(Oid trigid, bool pretty)
newrte - > rtekind = RTE_RELATION ;
newrte - > relid = trigrec - > tgrelid ;
newrte - > relkind = relkind ;
newrte - > eref = makeAlias ( " new " , NIL ) ;
newrte - > alias = makeAlias ( " new " , NIL ) ;
newrte - > eref = newrte - > alias ;
newrte - > lateral = false ;
newrte - > inh = false ;
newrte - > inFromCl = true ;
@ -694,6 +702,7 @@ pg_get_triggerdef_worker(Oid trigid, bool pretty)
memset ( & dpns , 0 , sizeof ( dpns ) ) ;
dpns . rtable = list_make2 ( oldrte , newrte ) ;
dpns . ctes = NIL ;
set_rtable_names ( & dpns , NIL , NULL ) ;
/* Set up context with one-deep namespace stack */
context . buf = & buf ;
@ -2176,7 +2185,8 @@ deparse_context_for(const char *aliasname, Oid relid)
rte - > rtekind = RTE_RELATION ;
rte - > relid = relid ;
rte - > relkind = RELKIND_RELATION ; /* no need for exactness here */
rte - > eref = makeAlias ( aliasname , NIL ) ;
rte - > alias = makeAlias ( aliasname , NIL ) ;
rte - > eref = rte - > alias ;
rte - > lateral = false ;
rte - > inh = false ;
rte - > inFromCl = true ;
@ -2184,6 +2194,7 @@ deparse_context_for(const char *aliasname, Oid relid)
/* Build one-element rtable */
dpns - > rtable = list_make1 ( rte ) ;
dpns - > ctes = NIL ;
set_rtable_names ( dpns , NIL , NULL ) ;
/* Return a one-deep namespace stack */
return list_make1 ( dpns ) ;
@ -2209,13 +2220,14 @@ deparse_context_for(const char *aliasname, Oid relid)
* most - closely - nested first . This is needed to resolve PARAM_EXEC Params .
* Note we assume that all the PlanStates share the same rtable .
*
* The plan ' s rangetable list must also be passed . We actually prefer to use
* the rangetable to resolve simple Vars , but the plan inputs are necessary
* for Vars with special varnos .
* The plan ' s rangetable list must also be passed , along with the per - RTE
* alias names assigned by a previous call to select_rtable_names_for_explain .
* ( We use the rangetable to resolve simple Vars , but the plan inputs are
* necessary for Vars with special varnos . )
*/
List *
deparse_context_for_planstate ( Node * planstate , List * ancestors ,
List * rtable )
List * rtable , List * rtable_names )
{
deparse_namespace * dpns ;
@ -2223,6 +2235,7 @@ deparse_context_for_planstate(Node *planstate, List *ancestors,
/* Initialize fields that stay the same across the whole plan tree */
dpns - > rtable = rtable ;
dpns - > rtable_names = rtable_names ;
dpns - > ctes = NIL ;
/* Set our attention on the specific plan node passed in */
@ -2233,6 +2246,142 @@ deparse_context_for_planstate(Node *planstate, List *ancestors,
return list_make1 ( dpns ) ;
}
/*
* select_rtable_names_for_explain - Select RTE aliases for EXPLAIN
*
* Determine the aliases we ' ll use during an EXPLAIN operation . This is
* just a frontend to set_rtable_names . We have to expose the aliases
* to EXPLAIN because EXPLAIN needs to know the right alias names to print .
*/
List *
select_rtable_names_for_explain ( List * rtable , Bitmapset * rels_used )
{
deparse_namespace dpns ;
memset ( & dpns , 0 , sizeof ( dpns ) ) ;
dpns . rtable = rtable ;
dpns . ctes = NIL ;
set_rtable_names ( & dpns , NIL , rels_used ) ;
return dpns . rtable_names ;
}
/*
* set_rtable_names : select RTE aliases to be used in printing variables
*
* We fill in dpns - > rtable_names with a list of names that is one - for - one with
* the already - filled dpns - > rtable list . Each RTE name is unique among those
* in the new namespace plus any ancestor namespaces listed in
* parent_namespaces .
*
* If rels_used isn ' t NULL , only RTE indexes listed in it are given aliases .
*/
static void
set_rtable_names ( deparse_namespace * dpns , List * parent_namespaces ,
Bitmapset * rels_used )
{
ListCell * lc ;
int rtindex = 1 ;
dpns - > rtable_names = NIL ;
foreach ( lc , dpns - > rtable )
{
RangeTblEntry * rte = ( RangeTblEntry * ) lfirst ( lc ) ;
char * refname ;
if ( rels_used & & ! bms_is_member ( rtindex , rels_used ) )
{
/* Ignore unreferenced RTE */
refname = NULL ;
}
else if ( rte - > alias )
{
/* If RTE has a user-defined alias, prefer that */
refname = rte - > alias - > aliasname ;
}
else if ( rte - > rtekind = = RTE_RELATION )
{
/* Use the current actual name of the relation */
refname = get_rel_name ( rte - > relid ) ;
}
else if ( rte - > rtekind = = RTE_JOIN )
{
/* Unnamed join has no refname */
refname = NULL ;
}
else
{
/* Otherwise use whatever the parser assigned */
refname = rte - > eref - > aliasname ;
}
/*
* If the selected name isn ' t unique , append digits to make it so
*/
if ( refname & &
! refname_is_unique ( refname , dpns , parent_namespaces ) )
{
char * modname = ( char * ) palloc ( strlen ( refname ) + 32 ) ;
int i = 0 ;
do
{
sprintf ( modname , " %s_%d " , refname , + + i ) ;
} while ( ! refname_is_unique ( modname , dpns , parent_namespaces ) ) ;
refname = modname ;
}
dpns - > rtable_names = lappend ( dpns - > rtable_names , refname ) ;
rtindex + + ;
}
}
/*
* refname_is_unique : is refname distinct from all already - chosen RTE names ?
*/
static bool
refname_is_unique ( char * refname , deparse_namespace * dpns ,
List * parent_namespaces )
{
ListCell * lc ;
foreach ( lc , dpns - > rtable_names )
{
char * oldname = ( char * ) lfirst ( lc ) ;
if ( oldname & & strcmp ( oldname , refname ) = = 0 )
return false ;
}
foreach ( lc , parent_namespaces )
{
deparse_namespace * olddpns = ( deparse_namespace * ) lfirst ( lc ) ;
ListCell * lc2 ;
foreach ( lc2 , olddpns - > rtable_names )
{
char * oldname = ( char * ) lfirst ( lc2 ) ;
if ( oldname & & strcmp ( oldname , refname ) = = 0 )
return false ;
}
}
return true ;
}
/*
* get_rtable_name : convenience function to get a previously assigned RTE alias
*
* The RTE must belong to the topmost namespace level in " context " .
*/
static char *
get_rtable_name ( int rtindex , deparse_context * context )
{
deparse_namespace * dpns = ( deparse_namespace * ) linitial ( context - > namespaces ) ;
Assert ( rtindex > 0 & & rtindex < = list_length ( dpns - > rtable_names ) ) ;
return ( char * ) list_nth ( dpns - > rtable_names , rtindex - 1 ) ;
}
/*
* set_deparse_planstate : set up deparse_namespace to parse subexpressions
* of a given PlanState node
@ -2534,6 +2683,7 @@ make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
memset ( & dpns , 0 , sizeof ( dpns ) ) ;
dpns . rtable = query - > rtable ;
dpns . ctes = query - > cteList ;
set_rtable_names ( & dpns , NIL , NULL ) ;
get_rule_expr ( qual , & context , false ) ;
}
@ -2680,6 +2830,7 @@ get_query_def(Query *query, StringInfo buf, List *parentnamespace,
memset ( & dpns , 0 , sizeof ( dpns ) ) ;
dpns . rtable = query - > rtable ;
dpns . ctes = query - > cteList ;
set_rtable_names ( & dpns , parentnamespace , NULL ) ;
switch ( query - > commandType )
{
@ -2899,7 +3050,6 @@ get_select_query_def(Query *query, deparse_context *context,
foreach ( l , query - > rowMarks )
{
RowMarkClause * rc = ( RowMarkClause * ) lfirst ( l ) ;
RangeTblEntry * rte = rt_fetch ( rc - > rti , query - > rtable ) ;
/* don't print implicit clauses */
if ( rc - > pushedDown )
@ -2912,7 +3062,8 @@ get_select_query_def(Query *query, deparse_context *context,
appendContextKeyword ( context , " FOR SHARE " ,
- PRETTYINDENT_STD , PRETTYINDENT_STD , 0 ) ;
appendStringInfo ( buf , " OF %s " ,
quote_identifier ( rte - > eref - > aliasname ) ) ;
quote_identifier ( get_rtable_name ( rc - > rti ,
context ) ) ) ;
if ( rc - > noWait )
appendStringInfo ( buf , " NOWAIT " ) ;
}
@ -3854,7 +4005,6 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
AttrNumber attnum ;
int netlevelsup ;
deparse_namespace * dpns ;
char * schemaname ;
char * refname ;
char * attname ;
@ -3874,6 +4024,7 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
if ( var - > varno > = 1 & & var - > varno < = list_length ( dpns - > rtable ) )
{
rte = rt_fetch ( var - > varno , dpns - > rtable ) ;
refname = ( char * ) list_nth ( dpns - > rtable_names , var - > varno - 1 ) ;
attnum = var - > varattno ;
}
else if ( var - > varno = = OUTER_VAR & & dpns - > outer_tlist )
@ -3993,61 +4144,41 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
return NULL ;
}
/* Identify names to use */
schemaname = NULL ; /* default assumptions */
refname = rte - > eref - > aliasname ;
/* Exceptions occur only if the RTE is alias-less */
if ( rte - > alias = = NULL )
/*
* If it ' s an unnamed join , look at the expansion of the alias variable .
* If it ' s a simple reference to one of the input vars , then recursively
* print the name of that var instead . ( This allows correct decompiling
* of cases where there are identically named columns on both sides of the
* join . ) When it ' s not a simple reference , we have to just print the
* unqualified variable name ( this can only happen with columns that were
* merged by USING or NATURAL clauses ) .
*
* This wouldn ' t work in decompiling plan trees , because we don ' t store
* joinaliasvars lists after planning ; but a plan tree should never
* contain a join alias variable .
*/
if ( rte - > rtekind = = RTE_JOIN & & rte - > alias = = NULL )
{
if ( rte - > rtekind = = RTE_RELATION )
{
/*
* It ' s possible that use of the bare refname would find another
* more - closely - nested RTE , or be ambiguous , in which case we need
* to specify the schemaname to avoid these errors .
*/
if ( find_rte_by_refname ( rte - > eref - > aliasname , context ) ! = rte )
schemaname = get_namespace_name ( get_rel_namespace ( rte - > relid ) ) ;
}
else if ( rte - > rtekind = = RTE_JOIN )
if ( rte - > joinaliasvars = = NIL )
elog ( ERROR , " cannot decompile join alias var in plan tree " ) ;
if ( attnum > 0 )
{
/*
* If it ' s an unnamed join , look at the expansion of the alias
* variable . If it ' s a simple reference to one of the input vars
* then recursively print the name of that var , instead . ( This
* allows correct decompiling of cases where there are identically
* named columns on both sides of the join . ) When it ' s not a
* simple reference , we have to just print the unqualified
* variable name ( this can only happen with columns that were
* merged by USING or NATURAL clauses ) .
*
* This wouldn ' t work in decompiling plan trees , because we don ' t
* store joinaliasvars lists after planning ; but a plan tree
* should never contain a join alias variable .
*/
if ( rte - > joinaliasvars = = NIL )
elog ( ERROR , " cannot decompile join alias var in plan tree " ) ;
if ( attnum > 0 )
{
Var * aliasvar ;
Var * aliasvar ;
aliasvar = ( Var * ) list_nth ( rte - > joinaliasvars , attnum - 1 ) ;
if ( IsA ( aliasvar , Var ) )
{
return get_variable ( aliasvar , var - > varlevelsup + levelsup ,
istoplevel , context ) ;
}
aliasvar = ( Var * ) list_nth ( rte - > joinaliasvars , attnum - 1 ) ;
if ( IsA ( aliasvar , Var ) )
{
return get_variable ( aliasvar , var - > varlevelsup + levelsup ,
istoplevel , context ) ;
}
/*
* Unnamed join has neither schemaname nor refname . ( Note : since
* it ' s unnamed , there is no way the user could have referenced it
* to create a whole - row Var for it . So we don ' t have to cover
* that case below . )
*/
refname = NULL ;
}
/*
* Unnamed join has no refname . ( Note : since it ' s unnamed , there is
* no way the user could have referenced it to create a whole - row Var
* for it . So we don ' t have to cover that case below . )
*/
Assert ( refname = = NULL ) ;
}
if ( attnum = = InvalidAttrNumber )
@ -4057,9 +4188,6 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
if ( refname & & ( context - > varprefix | | attname = = NULL ) )
{
if ( schemaname )
appendStringInfo ( buf , " %s. " ,
quote_identifier ( schemaname ) ) ;
appendStringInfoString ( buf , quote_identifier ( refname ) ) ;
appendStringInfoChar ( buf , ' . ' ) ;
}
@ -4289,6 +4417,7 @@ get_name_for_var_field(Var *var, int fieldno,
memset ( & mydpns , 0 , sizeof ( mydpns ) ) ;
mydpns . rtable = rte - > subquery - > rtable ;
mydpns . ctes = rte - > subquery - > cteList ;
set_rtable_names ( & mydpns , context - > namespaces , NULL ) ;
context - > namespaces = lcons ( & mydpns ,
context - > namespaces ) ;
@ -4406,6 +4535,7 @@ get_name_for_var_field(Var *var, int fieldno,
memset ( & mydpns , 0 , sizeof ( mydpns ) ) ;
mydpns . rtable = ctequery - > rtable ;
mydpns . ctes = ctequery - > cteList ;
set_rtable_names ( & mydpns , context - > namespaces , NULL ) ;
new_nslist = list_copy_tail ( context - > namespaces ,
ctelevelsup ) ;
@ -4467,47 +4597,6 @@ get_name_for_var_field(Var *var, int fieldno,
return NameStr ( tupleDesc - > attrs [ fieldno - 1 ] - > attname ) ;
}
/*
* find_rte_by_refname - look up an RTE by refname in a deparse context
*
* Returns NULL if there is no matching RTE or the refname is ambiguous .
*
* NOTE : this code is not really correct since it does not take account of
* the fact that not all the RTEs in a rangetable may be visible from the
* point where a Var reference appears . For the purposes we need , however ,
* the only consequence of a false match is that we might stick a schema
* qualifier on a Var that doesn ' t really need it . So it seems close
* enough .
*/
static RangeTblEntry *
find_rte_by_refname ( const char * refname , deparse_context * context )
{
RangeTblEntry * result = NULL ;
ListCell * nslist ;
foreach ( nslist , context - > namespaces )
{
deparse_namespace * dpns = ( deparse_namespace * ) lfirst ( nslist ) ;
ListCell * rtlist ;
foreach ( rtlist , dpns - > rtable )
{
RangeTblEntry * rte = ( RangeTblEntry * ) lfirst ( rtlist ) ;
if ( strcmp ( rte - > eref - > aliasname , refname ) = = 0 )
{
if ( result )
return NULL ; /* it's ambiguous */
result = rte ;
}
}
if ( result )
break ;
}
return result ;
}
/*
* Try to find the referenced expression for a PARAM_EXEC Param that might
* reference a parameter supplied by an upper NestLoop or SubPlan plan node .
@ -6649,6 +6738,7 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
{
int varno = ( ( RangeTblRef * ) jtnode ) - > rtindex ;
RangeTblEntry * rte = rt_fetch ( varno , query - > rtable ) ;
char * refname = get_rtable_name ( varno , context ) ;
bool gavealias = false ;
if ( rte - > lateral )
@ -6688,32 +6778,31 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
if ( rte - > alias ! = NULL )
{
appendStringInfo ( buf , " %s " ,
quote_identifier ( rte - > alias - > alias name ) ) ;
/* Always print alias if user provided one */
appendStringInfo ( buf , " %s " , quote_identifier ( ref name) ) ;
gavealias = true ;
}
else if ( rte - > rtekind = = RTE_RELATION & &
strcmp ( rte - > eref - > aliasname , get_relation_name ( rte - > relid ) ) ! = 0 )
else if ( rte - > rtekind = = RTE_RELATION )
{
/*
* Apparently the rel has been renamed since the rule was made .
* Emit a fake alias clause so that variable references will still
* work . This is not a 100 % solution but should work in most
* reasonable situations .
* No need to print alias if it ' s same as relation name ( this
* would normally be the case , but not if set_rtable_names had to
* resolve a conflict ) .
*/
appendStringInfo ( buf , " %s " ,
quote_identifier ( rte - > eref - > aliasname ) ) ;
gavealias = true ;
if ( strcmp ( refname , get_relation_name ( rte - > relid ) ) ! = 0 )
{
appendStringInfo ( buf , " %s " , quote_identifier ( refname ) ) ;
gavealias = true ;
}
}
else if ( rte - > rtekind = = RTE_FUNCTION )
{
/*
* For a function RTE , always give an alias . This covers possible
* For a function RTE , always print alias . This covers possible
* renaming of the function and / or instability of the
* FigureColname rules for things that aren ' t simple functions .
*/
appendStringInfo ( buf , " %s " ,
quote_identifier ( rte - > eref - > aliasname ) ) ;
appendStringInfo ( buf , " %s " , quote_identifier ( refname ) ) ;
gavealias = true ;
}
Tom Lane
13 years ago