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Project "Postgres-XC".

The branch, master has been updated
       via  e734d31c84a0a557bdfb172ee097a4b46d3868a7 (commit)
      from  719a5c822021427f7fd0eda354842b4b6b7ac381 (commit)


- Log -----------------------------------------------------------------
commit e734d31c84a0a557bdfb172ee097a4b46d3868a7
Author: Michael P <mic...@us...>
Date:   Mon Apr 18 14:51:14 2011 +0900

    Fix for bug 3167720: join optimizer error
    
    When running a query on multiple tables, if a constant
    expression was contained in WHERE clause, XC planner
    examined the constant expression all the time and checked
    if it was possible to avoid multiple node operation
    if the constant expression depended on a distributed table.
    
    This commits adds a check to verify in the case of multiple tables
    used in FROM clause if query can be safely pushed down to one
    target node on depending on the distribution type of each table.
    
    If SELECT clause is used on one distributed table and several
    replicated tables, this can be safely pushed down to a target node
    but in the case of multiple distributed tables used, all the nodes
    have to be targetted.

diff --git a/src/backend/pgxc/plan/planner.c b/src/backend/pgxc/plan/planner.c
index 019b6b8..dd570f4 100644
--- a/src/backend/pgxc/plan/planner.c
+++ b/src/backend/pgxc/plan/planner.c
@@ -1083,6 +1083,46 @@ examine_conditions_walker(Node *expr_node, XCWalkerContext *context)
 					if (!rel_loc_info1)
 						return true;
 
+					/* Check if this constant expression is targetting multiple tables */
+					if (list_length(context->query->rtable) > 1)
+					{
+						ListCell *lc;
+						RangeTblEntry *save_rte = NULL;
+						RelationLocInfo *save_loc_info;
+
+						foreach(lc, context->query->rtable)
+						{
+							RangeTblEntry *rte = lfirst(lc);
+
+							if (!save_rte)
+							{
+								save_rte = rte;
+								save_loc_info = GetRelationLocInfo(save_rte->relid);
+							}
+							else
+							{
+								/*
+								 * If there are two distributed tables at least
+								 * among the multiple tables, push down the query to all nodes.
+								 */
+								if (save_rte->relid != rte->relid)
+								{
+									RelationLocInfo *loc_info = GetRelationLocInfo(rte->relid);
+
+									if (loc_info->locatorType != LOCATOR_TYPE_REPLICATED &&
+										save_loc_info->locatorType != LOCATOR_TYPE_REPLICATED)
+										return true;
+									if (loc_info->locatorType != LOCATOR_TYPE_REPLICATED &&
+										save_loc_info->locatorType == LOCATOR_TYPE_REPLICATED)
+									{
+										save_rte = rte;
+										save_loc_info = loc_info;
+									}
+								}
+							}
+						}
+					}
+
 					/* If hash or modulo partitioned, check if the part column was used */
 					if (IsHashColumn(rel_loc_info1, column_base->colname) ||
 						IsModuloColumn(rel_loc_info1, column_base->colname))

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

Summary of changes:
 src/backend/pgxc/plan/planner.c |   40 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)


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