- 04 8月, 2008 1 次提交
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由 Tom Lane 提交于
sorting. The infrastructure for this was all in place already; it's only necessary to fix the planner to not assume that sorting is always an available option.
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- 03 8月, 2008 1 次提交
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由 Tom Lane 提交于
as per my recent proposal: 1. Fold SortClause and GroupClause into a single node type SortGroupClause. We were already relying on them to be struct-equivalent, so using two node tags wasn't accomplishing much except to get in the way of comparing items with equal(). 2. Add an "eqop" field to SortGroupClause to carry the associated equality operator. This is cheap for the parser to get at the same time it's looking up the sort operator, and storing it eliminates the need for repeated not-so-cheap lookups during planning. In future this will also let us represent GROUP/DISTINCT operations on datatypes that have hash opclasses but no btree opclasses (ie, they have equality but no natural sort order). The previous representation simply didn't work for that, since its only indicator of comparison semantics was a sort operator. 3. Add a hasDistinctOn boolean to struct Query to explicitly record whether the distinctClause came from DISTINCT or DISTINCT ON. This allows removing some complicated and not 100% bulletproof code that attempted to figure that out from the distinctClause alone. This patch doesn't in itself create any new capability, but it's necessary infrastructure for future attempts to use hash-based grouping for DISTINCT and UNION/INTERSECT/EXCEPT.
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- 01 8月, 2008 1 次提交
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由 Tom Lane 提交于
to represent DISTINCT or DISTINCT ON. This gets rid of a longstanding annoyance that a view or rule using SELECT DISTINCT will be dumped out with an overspecified ORDER BY list, and is one small step along the way to decoupling DISTINCT and ORDER BY enough so that hash-based implementation of DISTINCT will be possible. In passing, improve transformDistinctClause so that it doesn't reject duplicate DISTINCT ON items, as was reported by Steve Midgley a couple weeks ago.
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- 10 7月, 2008 1 次提交
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由 Tom Lane 提交于
the current query level that aren't in fact output parameters of the current initPlans. (This means, for example, output parameters of regular subplans.) To make this work correctly for output parameters coming from sibling initplans requires rejiggering the API of SS_finalize_plan just a bit: we need the siblings to be visible to it, rather than hidden as SS_make_initplan_from_plan had been doing. This is really part of my response to bug #4290, but I concluded this part probably shouldn't be back-patched, since all that it's doing is to make a debugging cross-check tighter.
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- 03 5月, 2008 1 次提交
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由 Tom Lane 提交于
retrieved to be controlled through a GUC variable. Robert Hell
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- 18 4月, 2008 1 次提交
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由 Tom Lane 提交于
we had several code paths where a physical tlist could be used for the input to a Sort node, which is a dumb idea because any unneeded table columns will increase the volume of data the sort has to push around. (Unfortunately the easy-looking fix of calling disuse_physical_tlist during make_sort_xxx doesn't work because in most cases we're already committed to the current input tlist --- it's been marked with sort column numbers, or we've built grouping column numbers using it, etc. The tlist has to be selected properly at the calling level before we start constructing sort-col information. This is easy enough to do, we were just failing to take the point into consideration.) Back-patch to 8.3. I believe the problem probably exists clear back to 7.4 when the physical tlist optimization was added, but I'm afraid to back-patch further than 8.3 without a great deal more study than I want to put into it. The code in this area has drifted a lot over time. The real-world importance of these code paths is uncertain anyway --- I think in many cases we'd probably prefer hash-based methods.
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- 01 4月, 2008 1 次提交
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由 Tom Lane 提交于
eval_const_expressions needs to be passed the PlannerInfo ("root") structure, because in some cases we want it to substitute values for Param nodes. (So "constant" is not so constant as all that ...) This mistake partially disabled optimization of unnamed extended-Query statements in 8.3: in particular the LIKE-to-indexscan optimization would never be applied if the LIKE pattern was passed as a parameter, and constraint exclusion depending on a parameter value didn't work either.
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- 29 3月, 2008 1 次提交
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由 Tom Lane 提交于
Whatever we do about that, this isn't the path to the solution.
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- 28 3月, 2008 2 次提交
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由 Tom Lane 提交于
useless for an ungrouped-aggregate query holds regardless of whether optimize_minmax_aggregates succeeds. So we might as well apply the optimization in any case. I'll leave 8.3 as it was, since this version is a tad more invasive than my earlier patch.
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由 Tom Lane 提交于
the query result must be exactly one row (since we don't do this when there's any GROUP BY). Therefore any ORDER BY or DISTINCT attached to the query is useless and can be dropped. Aside from saving useless cycles, this protects us against problems with matching the hacked-up tlist entries to sort clauses, as seen in a bug report from Taiki Yamaguchi. We might need to work harder if we ever try to optimize grouped queries with this approach, but this solution will do for now.
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- 19 3月, 2008 1 次提交
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由 Tom Lane 提交于
are declared to return set, and consist of just a single SELECT. We can replace the FROM-item with a sub-SELECT and then optimize much as if we were dealing with a view. Patch from Richard Rowell, cleaned up by me.
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- 02 1月, 2008 1 次提交
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由 Bruce Momjian 提交于
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- 16 11月, 2007 2 次提交
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由 Bruce Momjian 提交于
avoid this problem in the future.)
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由 Bruce Momjian 提交于
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- 12 10月, 2007 1 次提交
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由 Tom Lane 提交于
a relation as a reason to invalidate a plan when the relation changes. This handles scenarios such as dropping/recreating a sequence that is referenced by nextval('seq') in a cached plan. Rather than teach plancache.c all about digging through plan trees to find regclass Consts, we charge the planner's setrefs.c with making a list of the relation OIDs on which each plan depends. That way the list can be built cheaply during a plan tree traversal that has to happen anyway. Per bug #3662 and subsequent discussion.
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- 21 9月, 2007 1 次提交
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由 Tom Lane 提交于
columns, and the new version can be stored on the same heap page, we no longer generate extra index entries for the new version. Instead, index searches follow the HOT-chain links to ensure they find the correct tuple version. In addition, this patch introduces the ability to "prune" dead tuples on a per-page basis, without having to do a complete VACUUM pass to recover space. VACUUM is still needed to clean up dead index entries, however. Pavan Deolasee, with help from a bunch of other people.
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- 27 5月, 2007 1 次提交
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由 Tom Lane 提交于
inheritance child of an UPDATE/DELETE target relation can be excluded by constraints. I had rearranged some code in set_append_rel_pathlist() to avoid "useless" work when a child is excluded, but overdid it and left the child with no cheapest_path entry, causing possible failure later if the appendrel was involved in a join. Also, it seems that the dummy plan generated by inheritance_planner() when all branches are excluded has to be a bit less dummy now than was required in 8.2. Per report from Jan Wieck. Add his test case to the regression tests.
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- 26 5月, 2007 1 次提交
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由 Tom Lane 提交于
and/or create plans for hypothetical situations; in particular, investigate plans that would be generated using hypothetical indexes. This is a heavily-rewritten version of the hooks proposed by Gurjeet Singh for his Index Advisor project. In this formulation, the index advisor can be entirely a loadable module instead of requiring a significant part to be in the core backend, and plans can be generated for hypothetical indexes without requiring the creation and rolling-back of system catalog entries. The index advisor patch as-submitted is not compatible with these hooks, but it needs significant work anyway due to other 8.2-to-8.3 planner changes. With these hooks in the core backend, development of the advisor can proceed as a pgfoundry project.
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- 04 5月, 2007 1 次提交
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由 Tom Lane 提交于
need be returned. We keep a heap of the current best N tuples and sift-up new tuples into it as we scan the input. For M input tuples this means only about M*log(N) comparisons instead of M*log(M), not to mention a lot less workspace when N is small --- avoiding spill-to-disk for large M is actually the most attractive thing about it. Patch includes planner and executor support for invoking this facility in ORDER BY ... LIMIT queries. Greg Stark, with some editorialization by moi.
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- 28 4月, 2007 1 次提交
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由 Tom Lane 提交于
types of unspecified parameters when submitted via extended query protocol. This worked in 8.2 but I had broken it during plancache changes. DECLARE CURSOR is now treated almost exactly like a plain SELECT through parse analysis, rewrite, and planning; only just before sending to the executor do we divert it away to ProcessUtility. This requires a special-case check in a number of places, but practically all of them were already special-casing SELECT INTO, so it's not too ugly. (Maybe it would be a good idea to merge the two by treating IntoClause as a form of utility statement? Not going to worry about that now, though.) That approach doesn't work for EXPLAIN, however, so for that I punted and used a klugy solution of running parse analysis an extra time if under extended query protocol.
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- 16 4月, 2007 1 次提交
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由 Tom Lane 提交于
access to the planner's cursor-related planning options, and provide new FETCH/MOVE routines that allow access to the full power of those commands. Small refactoring of planner(), pg_plan_query(), and pg_plan_queries() APIs to make it convenient to pass the planning options down from SPI. This is the core-code portion of Pavel Stehule's patch for scrollable cursor support in plpgsql; I'll review and apply the plpgsql changes separately.
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- 27 2月, 2007 1 次提交
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由 Tom Lane 提交于
parent query's EState. Now that there's a single flat rangetable for both the main plan and subplans, there's no need anymore for a separate EState, and removing it allows cleaning up some crufty code in nodeSubplan.c and nodeSubqueryscan.c. Should be a tad faster too, although any difference will probably be hard to measure. This is the last bit of subsidiary mop-up work from changing to a flat rangetable.
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- 23 2月, 2007 1 次提交
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由 Tom Lane 提交于
useless substructure for its RangeTblEntry nodes. (I chose to keep using the same struct node type and just zero out the link fields for unneeded info, rather than making a separate ExecRangeTblEntry type --- it seemed too fragile to have two different rangetable representations.) Along the way, put subplans into a list in the toplevel PlannedStmt node, and have SubPlan nodes refer to them by list index instead of direct pointers. Vadim wanted to do that years ago, but I never understood what he was on about until now. It makes things a *whole* lot more robust, because we can stop worrying about duplicate processing of subplans during expression tree traversals. That's been a constant source of bugs, and it's finally gone. There are some consequent simplifications yet to be made, like not using a separate EState for subplans in the executor, but I'll tackle that later.
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- 21 2月, 2007 1 次提交
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由 Tom Lane 提交于
storing mostly-redundant Query trees in prepared statements, portals, etc. To replace Query, a new node type called PlannedStmt is inserted by the planner at the top of a completed plan tree; this carries just the fields of Query that are still needed at runtime. The statement lists kept in portals etc. now consist of intermixed PlannedStmt and bare utility-statement nodes --- no Query. This incidentally allows us to remove some fields from Query and Plan nodes that shouldn't have been there in the first place. Still to do: simplify the execution-time range table; at the moment the range table passed to the executor still contains Query trees for subqueries. initdb forced due to change of stored rules.
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- 19 2月, 2007 1 次提交
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由 Tom Lane 提交于
this code was last gone over, there wasn't really any alternative to globals because we didn't have the PlannerInfo struct being passed all through the planner code. Now that we do, we can restructure things to avoid non-reentrancy. I'm fooling with this because otherwise I'd have had to add another global variable for the planned compact range table list.
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- 21 1月, 2007 1 次提交
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由 Tom Lane 提交于
representation of equivalence classes of variables. This is an extensive rewrite, but it brings a number of benefits: * planner no longer fails in the presence of "incomplete" operator families that don't offer operators for every possible combination of datatypes. * avoid generating and then discarding redundant equality clauses. * remove bogus assumption that derived equalities always use operators named "=". * mergejoins can work with a variety of sort orders (e.g., descending) now, instead of tying each mergejoinable operator to exactly one sort order. * better recognition of redundant sort columns. * can make use of equalities appearing underneath an outer join.
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- 11 1月, 2007 1 次提交
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由 Tom Lane 提交于
which comparison operators to use for plan nodes involving tuple comparison (Agg, Group, Unique, SetOp). Formerly the executor looked up the default equality operator for the datatype, which was really pretty shaky, since it's possible that the data being fed to the node is sorted according to some nondefault operator class that could have an incompatible idea of equality. The planner knows what it has sorted by and therefore can provide the right equality operator to use. Also, this change moves a couple of catalog lookups out of the executor and into the planner, which should help startup time for pre-planned queries by some small amount. Modify the planner to remove some other cavalier assumptions about always being able to use the default operators. Also add "nulls first/last" info to the Plan node for a mergejoin --- neither the executor nor the planner can cope yet, but at least the API is in place.
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- 06 1月, 2007 1 次提交
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由 Bruce Momjian 提交于
back-stamped for this.
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- 04 10月, 2006 1 次提交
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由 Bruce Momjian 提交于
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- 12 8月, 2006 1 次提交
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由 Tom Lane 提交于
plpgsql support to come later. Along the way, convert execMain's SELECT INTO support into a DestReceiver, in order to eliminate some ugly special cases. Jonah Harris and Tom Lane
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- 06 8月, 2006 1 次提交
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由 Tom Lane 提交于
list, when some of the child rels have been excluded by constraint exclusion. This doesn't save a huge amount of time but it'll save some, and it makes the EXPLAIN output look saner. We already did the equivalent thing in set_append_rel_pathlist(), but not here.
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- 02 8月, 2006 1 次提交
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由 Joe Conway 提交于
(e.g. "INSERT ... VALUES (...), (...), ...") and elsewhere as allowed by the spec. (e.g. similar to a FROM clause subselect). initdb required. Joe Conway and Tom Lane.
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- 27 7月, 2006 1 次提交
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由 Tom Lane 提交于
eliminate unnecessary code, force initdb because stored rules change (limit nodes are now supposed to be int8 not int4 expressions). Update comments and error messages, which still all said 'integer'.
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- 26 7月, 2006 1 次提交
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由 Bruce Momjian 提交于
Dhanaraj M
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- 14 7月, 2006 1 次提交
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由 Bruce Momjian 提交于
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- 12 7月, 2006 1 次提交
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由 Bruce Momjian 提交于
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- 02 7月, 2006 1 次提交
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由 Tom Lane 提交于
clauses containing no variables and no volatile functions. Such a clause can be used as a one-time qual in a gating Result plan node, to suppress plan execution entirely when it is false. Even when the clause is true, putting it in a gating node wins by avoiding repeated evaluation of the clause. In previous PG releases, query_planner() would do this for pseudoconstant clauses appearing at the top level of the jointree, but there was no ability to generate a gating Result deeper in the plan tree. To fix it, get rid of the special case in query_planner(), and instead process pseudoconstant clauses through the normal RestrictInfo qual distribution mechanism. When a pseudoconstant clause is found attached to a path node in create_plan(), pull it out and generate a gating Result at that point. This requires special-casing pseudoconstants in selectivity estimation and cost_qual_eval, but on the whole it's pretty clean. It probably even makes the planner a bit faster than before for the normal case of no pseudoconstants, since removing pull_constant_clauses saves one useless traversal of the qual tree. Per gripe from Phil Frost.
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- 29 6月, 2006 1 次提交
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由 Tom Lane 提交于
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- 05 3月, 2006 1 次提交
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由 Bruce Momjian 提交于
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- 04 2月, 2006 1 次提交
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由 Tom Lane 提交于
thereby sharing code with the inheritance case. This puts the UNION-ALL-view approach to partitioned tables on par with inheritance, so far as constraint exclusion is concerned: it works either way. (Still need to update the docs to say so.) The definition of "simple UNION ALL" is a little simpler than I would like --- basically the union arms can only be SELECT * FROM foo --- but it's good enough for partitioned-table cases.
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