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Do some minor code refactoring in preparation for changing the APIs of

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find_inheritance_children() and find_all_inheritors().  I got annoyed that
these are buried inside the planner but mostly used elsewhere.  So, create
a new file catalog/pg_inherits.c and put them there, along with a couple
of other functions that search pg_inherits.

The code that modifies pg_inherits is (still) in tablecmds.c --- it's
kind of entangled with unrelated code that modifies pg_depend and other
stuff, so pulling it out seemed like a bigger change than I wanted to make
right now.  But this file provides a natural home for it if anyone ever
gets around to that.

This commit just moves code around; it doesn't change anything, except
I succumbed to the temptation to make a couple of trivial optimizations
in typeInheritsFrom().
This commit is contained in:
Tom Lane
2009-05-12 00:56:05 +00:00
parent 6480c143ee
commit 0ada559187
12 changed files with 282 additions and 242 deletions
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45
src/backend/optimizer/prep/prepunion.c
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@@ -22,7 +22,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.168 2009/03/31 22:12:48 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.169 2009/05/12 00:56:05 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -32,6 +32,7 @@
#include "access/heapam.h"
#include "access/sysattr.h"
#include "catalog/namespace.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_type.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
@@ -39,7 +40,6 @@
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/plancat.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
@@ -1081,47 +1081,6 @@ generate_setop_grouplist(SetOperationStmt *op, List *targetlist)
}
/*
* find_all_inheritors -
* Returns a list of relation OIDs including the given rel plus
* all relations that inherit from it, directly or indirectly.
*/
List *
find_all_inheritors(Oid parentrel)
{
List *rels_list;
ListCell *l;
/*
* We build a list starting with the given rel and adding all direct and
* indirect children. We can use a single list as both the record of
* already-found rels and the agenda of rels yet to be scanned for more
* children. This is a bit tricky but works because the foreach() macro
* doesn't fetch the next list element until the bottom of the loop.
*/
rels_list = list_make1_oid(parentrel);
foreach(l, rels_list)
{
Oid currentrel = lfirst_oid(l);
List *currentchildren;
/* Get the direct children of this rel */
currentchildren = find_inheritance_children(currentrel);
/*
* Add to the queue only those children not already seen. This avoids
* making duplicate entries in case of multiple inheritance paths from
* the same parent. (It'll also keep us from getting into an infinite
* loop, though theoretically there can't be any cycles in the
* inheritance graph anyway.)
*/
rels_list = list_concat_unique_oid(rels_list, currentchildren);
}
return rels_list;
}
/*
* expand_inherited_tables
* Expand each rangetable entry that represents an inheritance set