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Remove useless whitespace at end of lines

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Peter Eisentraut
2010-11-23 22:27:50 +02:00
parent 44475e782f
commit fc946c39ae
517 changed files with 3463 additions and 3508 deletions
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34
src/backend/optimizer/plan/README
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@@ -37,19 +37,19 @@ This is some implementation notes and opened issues...
First, implementation uses new type of parameters - PARAM_EXEC - to deal
with correlation Vars. When query_planner() is called, it first tries to
replace all upper queries Var referenced in current query with Param of
this type. Some global variables are used to keep mapping of Vars to
Params and Params to Vars.
replace all upper queries Var referenced in current query with Param of
this type. Some global variables are used to keep mapping of Vars to
Params and Params to Vars.
After this, all current query' SubLinks are processed: for each SubLink
found in query' qual union_planner() (old planner() function) will be
called to plan corresponding subselect (union_planner() calls
query_planner() for "simple" query and supports UNIONs). After subselect
are planned, optimizer knows about is this correlated, un-correlated or
_undirect_ correlated (references some grand-parent Vars but no parent
ones: uncorrelated from the parent' point of view) query.
After this, all current query' SubLinks are processed: for each SubLink
found in query' qual union_planner() (old planner() function) will be
called to plan corresponding subselect (union_planner() calls
query_planner() for "simple" query and supports UNIONs). After subselect
are planned, optimizer knows about is this correlated, un-correlated or
_undirect_ correlated (references some grand-parent Vars but no parent
ones: uncorrelated from the parent' point of view) query.
For uncorrelated and undirect correlated subqueries of EXPRession or
For uncorrelated and undirect correlated subqueries of EXPRession or
EXISTS type SubLinks will be replaced with "normal" clauses from
SubLink->Oper list (I changed this list to be list of EXPR nodes,
not just Oper ones). Right sides of these nodes are replaced with
@@ -81,7 +81,7 @@ plan->qual) - to initialize them and let them know about changed
Params (from the list of their "interests").
After all SubLinks are processed, query_planner() calls qual'
canonificator and does "normal" work. By using Params optimizer
canonificator and does "normal" work. By using Params optimizer
is mostly unchanged.
Well, Executor. To get subplans re-evaluated without ExecutorStart()
@@ -91,7 +91,7 @@ on each call) ExecReScan() now supports most of Plan types...
Explanation of EXPLAIN.
vac=> explain select * from tmp where x >= (select max(x2) from test2
vac=> explain select * from tmp where x >= (select max(x2) from test2
where y2 = y and exists (select * from tempx where tx = x));
NOTICE: QUERY PLAN:
@@ -128,17 +128,17 @@ Opened issues.
for each parent tuple - very slow...
Results of some test. TMP is table with x,y (int4-s), x in 0-9,
y = 100 - x, 1000 tuples (10 duplicates of each tuple). TEST2 is table
y = 100 - x, 1000 tuples (10 duplicates of each tuple). TEST2 is table
with x2, y2 (int4-s), x2 in 1-99, y2 = 100 -x2, 10000 tuples (100 dups).
Trying
Trying
select * from tmp where x >= (select max(x2) from test2 where y2 = y);
and
begin;
select y as ty, max(x2) as mx into table tsub from test2, tmp
select y as ty, max(x2) as mx into table tsub from test2, tmp
where y2 = y group by ty;
vacuum tsub;
select x, y from tmp, tsub where x >= mx and y = ty;