aboutsummaryrefslogtreecommitdiff
path: root/src/backend/commands/explain.c
Commit message (Collapse)AuthorAge
...
* Support window functions a la SQL:2008.Tom Lane2008-12-28
| | | | Hitoshi Harada, with some kibitzing from Heikki and Tom.
* Some infrastructure changes for the upcoming auto-explain contrib module:Tom Lane2008-11-19
| | | | | | | | | | | | | | | | | | | | | | * Refactor explain.c slightly to export a convenient-to-use subroutine for printing EXPLAIN results. * Provide hooks for plugins to get control at ExecutorStart and ExecutorEnd as well as ExecutorRun. * Add some minimal support for tracking the total runtime of ExecutorRun. This code won't actually do anything unless a plugin prods it to. * Change the API of the DefineCustomXXXVariable functions to allow nonzero "flags" to be specified for a custom GUC variable. While at it, also make the "bootstrap" default value for custom GUCs be explicitly specified as a parameter to these functions. This is to eliminate confusion over where the default comes from, as has been expressed in the past by some users of the custom-variable facility. * Refactor GUC code a bit to ensure that a custom variable gets initialized to something valid (like its default value) even if the placeholder value was invalid.
* Fix up ruleutils.c for CTE features. The main problem was thatTom Lane2008-10-06
| | | | | | | | | | | | | | | | get_name_for_var_field didn't have enough context to interpret a reference to a CTE query's output. Fixing this requires separate hacks for the regular deparse case (pg_get_ruledef) and for the EXPLAIN case, since the available context information is quite different. It's pretty nearly parallel to the existing code for SUBQUERY RTEs, though. Also, add code to make sure we qualify a relation name that matches a CTE name; else the CTE will mistakenly capture the reference when reloading the rule. In passing, fix a pre-existing problem with get_name_for_var_field not working on variables in targetlists of SubqueryScan plan nodes. Although latent all along, this wasn't a problem until we made EXPLAIN VERBOSE try to print targetlists. To do this, refactor the deparse_context_for_plan API so that the special case for SubqueryScan is all on ruleutils.c's side.
* Implement SQL-standard WITH clauses, including WITH RECURSIVE.Tom Lane2008-10-04
| | | | | | | | | | | | | There are some unimplemented aspects: recursive queries must use UNION ALL (should allow UNION too), and we don't have SEARCH or CYCLE clauses. These might or might not get done for 8.4, but even without them it's a pretty useful feature. There are also a couple of small loose ends and definitional quibbles, which I'll send a memo about to pgsql-hackers shortly. But let's land the patch now so we can get on with other development. Yoshiyuki Asaba, with lots of help from Tatsuo Ishii and Tom Lane
* Cause the output from debug_print_parse, debug_print_rewritten, andTom Lane2008-08-19
| | | | | | | | debug_print_plan to appear at LOG message level, not DEBUG1 as historically. Make debug_pretty_print default to on. Also, cause plans generated via EXPLAIN to be subject to debug_print_plan. This is all to make debug_print_plan a reasonably comfortable substitute for the former behavior of EXPLAIN VERBOSE.
* Implement SEMI and ANTI joins in the planner and executor. (Semijoins replaceTom Lane2008-08-14
| | | | | | | | | | | | | | the old JOIN_IN code, but antijoins are new functionality.) Teach the planner to convert appropriate EXISTS and NOT EXISTS subqueries into semi and anti joins respectively. Also, LEFT JOINs with suitable upper-level IS NULL filters are recognized as being anti joins. Unify the InClauseInfo and OuterJoinInfo infrastructure into "SpecialJoinInfo". With that change, it becomes possible to associate a SpecialJoinInfo with every join attempt, which permits some cleanup of join selectivity estimation. That needs to be taken much further than this patch does, but the next step is to change the API for oprjoin selectivity functions, which seems like material for a separate patch. So for the moment the output size estimates for semi and especially anti joins are quite bogus.
* Support hashing for duplicate-elimination in INTERSECT and EXCEPT queries.Tom Lane2008-08-07
| | | | | | | | | | This completes my project of improving usage of hashing for duplicate elimination (aggregate functions with DISTINCT remain undone, but that's for some other day). As with the previous patches, this means we can INTERSECT/EXCEPT on datatypes that can hash but not sort, and it means that INTERSECT/EXCEPT without ORDER BY are no longer certain to produce sorted output.
* Move the "instr_time" typedef and associated macros into a new headerTom Lane2008-05-14
| | | | | | | | | file portability/instr_time.h, and add a couple more macros to eliminate some abstraction leakage we formerly had. Also update psql to use this header instead of its own copy of nearly the same code. This commit in itself is just code cleanup and shouldn't change anything. It lays some groundwork for the upcoming function-stats patch, though.
* Improve snapshot manager by keeping explicit track of snapshots.Alvaro Herrera2008-05-12
| | | | | | | | | | | | | There are two ways to track a snapshot: there's the "registered" list, which is used for arbitrary long-lived snapshots; and there's the "active stack", which is used for the snapshot that is considered "active" at any time. This also allows users of snapshots to stop worrying about snapshot memory allocation and freeing, and about using PG_TRY blocks around ActiveSnapshot assignment. This is all done automatically now. As a consequence, this allows us to reset MyProc->xmin when there are no more snapshots registered in the current backend, reducing the impact that long-running transactions have on VACUUM.
* Cause EXPLAIN's VERBOSE option to print the target list (output column list)Tom Lane2008-04-18
| | | | | | | | | | of each plan node, instead of its former behavior of dumping the internal representation of the plan tree. The latter display is still available for those who really want it (see debug_print_plan), but uses for it are certainly few and and far between. Per discussion. This patch also removes the explain_pretty_print GUC, which is obsoleted by the change.
* Add some code to EXPLAIN to show the targetlist (ie, output columns)Tom Lane2008-04-17
| | | | | | of each plan node. For the moment this is debug support only and is not enabled unless EXPLAIN_PRINT_TLISTS is defined at build time. Later I'll see about the idea of letting EXPLAIN VERBOSE do it.
* Rename snapmgmt.c/h to snapmgr.c/h, for consistency with other files.Alvaro Herrera2008-03-26
| | | | Per complaint from Tom Lane.
* Separate snapshot management code from tuple visibility code, create aAlvaro Herrera2008-03-26
| | | | | | | | | | | | | snapmgmt.c file for the former. The header files have also been reorganized in three parts: the most basic snapshot definitions are now in a new file snapshot.h, and the also new snapmgmt.h keeps the definitions for snapmgmt.c. tqual.h has been reduced to the bare minimum. This patch is just a first step towards managing live snapshots within a transaction; there is no functionality change. Per my proposal to pgsql-patches on 20080318191940.GB27458@alvh.no-ip.org and subsequent discussion.
* Update copyrights in source tree to 2008.Bruce Momjian2008-01-01
|
* Avoid incrementing the CommandCounter when CommandCounterIncrement is calledTom Lane2007-11-30
| | | | | | | | | | | | | | | | | | | | but no database changes have been made since the last CommandCounterIncrement. This should result in a significant improvement in the number of "commands" that can typically be performed within a transaction before hitting the 2^32 CommandId size limit. In particular this buys back (and more) the possible adverse consequences of my previous patch to fix plan caching behavior. The implementation requires tracking whether the current CommandCounter value has been "used" to mark any tuples. CommandCounter values stored into snapshots are presumed not to be used for this purpose. This requires some small executor changes, since the executor used to conflate the curcid of the snapshot it was using with the command ID to mark output tuples with. Separating these concepts allows some small simplifications in executor APIs. Something for the TODO list: look into having CommandCounterIncrement not do AcceptInvalidationMessages. It seems fairly bogus to be doing it there, but exactly where to do it instead isn't clear, and I'm disinclined to mess with asynchronous behavior during late beta.
* Re-run pgindent with updated list of typedefs. (Updated README shouldBruce Momjian2007-11-15
| | | | avoid this problem in the future.)
* pgindent run for 8.3.Bruce Momjian2007-11-15
|
* Arrange to cache a ResultRelInfo in the executor's EState for relations thatTom Lane2007-08-15
| | | | | | | | | | | | | are not one of the query's defined result relations, but nonetheless have triggers fired against them while the query is active. This was formerly impossible but can now occur because of my recent patch to fix the firing order for RI triggers. Caching a ResultRelInfo avoids duplicating work by repeatedly opening and closing the same relation, and also allows EXPLAIN ANALYZE to "see" and report on these extra triggers. Use the same mechanism to cache open relations when firing deferred triggers at transaction shutdown; this replaces the former one-element-cache strategy used in that case, and should improve performance a bit when there are deferred triggers on a number of relations.
* Create hooks to let a loadable plugin monitor (or even replace) the plannerTom Lane2007-05-25
| | | | | | | | | | | | | | | 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.
* Add a line to the EXPLAIN ANALYZE output for a Sort node, showing theTom Lane2007-05-04
| | | | actual sort strategy and amount of space used. By popular demand.
* Modify processing of DECLARE CURSOR and EXPLAIN so that they can resolve theTom Lane2007-04-27
| | | | | | | | | | | | | | 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.
* Expose more cursor-related functionality in SPI: specifically, allowTom Lane2007-04-16
| | | | | | | | | | | 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.
* First phase of plan-invalidation project: create a plan cache managementTom Lane2007-03-13
| | | | | | | | | | | | | | | | module and teach PREPARE and protocol-level prepared statements to use it. In service of this, rearrange utility-statement processing so that parse analysis does not assume table schemas can't change before execution for utility statements (necessary because we don't attempt to re-acquire locks for utility statements when reusing a stored plan). This requires some refactoring of the ProcessUtility API, but it ends up cleaner anyway, for instance we can get rid of the QueryContext global. Still to do: fix up SPI and related code to use the plan cache; I'm tempted to try to make SQL functions use it too. Also, there are at least some aspects of system state that we want to ensure remain the same during a replan as in the original processing; search_path certainly ought to behave that way for instance, and perhaps there are others.
* Now that plans have flat rangetable lists, it's a lot easier to get EXPLAIN toTom Lane2007-02-23
| | | | | | | | | | | | drill down into subplan targetlists to print the referent expression for an OUTER or INNER var in an upper plan node. Hence, make it do that always, and banish the old hack of showing "?columnN?" when things got too complicated. Along the way, fix an EXPLAIN bug I introduced by suppressing subqueries from execution-time range tables: get_name_for_var_field() assumed it could look at rte->subquery to find out the real type of a RECORD var. That doesn't work anymore, but instead we can look at the input plan of the SubqueryScan plan node.
* Change Agg and Group nodes so that Vars contained in their targetlistsTom Lane2007-02-22
| | | | | | | and quals have varno OUTER, rather than zero, to indicate a reference to an output of their lefttree subplan. This is consistent with the way that every other upper-level node type does it, and allows some simplifications in setrefs.c and EXPLAIN.
* Turn the rangetable used by the executor into a flat list, and avoid storingTom Lane2007-02-22
| | | | | | | | | | | | | | | | | 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.
* Remove the Query structure from the executor's API. This allows us to stopTom Lane2007-02-20
| | | | | | | | | | | | | | | 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.
* Put function expressions and values lists into FunctionScan and ValuesScanTom Lane2007-02-19
| | | | | | plan nodes, so that the executor does not need to get these items from the range table at runtime. This will avoid needing to include these fields in the compact range table I'm expecting to make the executor use.
* Fix up foreign-key mechanism so that there is a sound semantic basis for theTom Lane2007-02-14
| | | | | | | | | | | | | | | | | | | | | equality checks it applies, instead of a random dependence on whatever operators might be named "=". The equality operators will now be selected from the opfamily of the unique index that the FK constraint depends on to enforce uniqueness of the referenced columns; therefore they are certain to be consistent with that index's notion of equality. Among other things this should fix the problem noted awhile back that pg_dump may fail for foreign-key constraints on user-defined types when the required operators aren't in the search path. This also means that the former warning condition about "foreign key constraint will require costly sequential scans" is gone: if the comparison condition isn't indexable then we'll reject the constraint entirely. All per past discussions. Along the way, make the RI triggers look into pg_constraint for their information, instead of using pg_trigger.tgargs; and get rid of the always error-prone fixed-size string buffers in ri_triggers.c in favor of building up the RI queries in StringInfo buffers. initdb forced due to columns added to pg_constraint and pg_trigger.
* Update CVS HEAD for 2007 copyright. Back branches are typically notBruce Momjian2007-01-05
| | | | back-stamped for this.
* pgindent run for 8.2.Bruce Momjian2006-10-04
|
* Change processing of extended-Query mode so that an unnamed statementTom Lane2006-09-06
| | | | | | | | that has parameters is always planned afresh for each Bind command, treating the parameter values as constants in the planner. This removes the performance penalty formerly often paid for using out-of-line parameters --- with this definition, the planner can do constant folding, LIKE optimization, etc. After a suggestion by Andrew@supernews.
* Add support for multi-row VALUES clauses as part of INSERT statementsJoe Conway2006-08-02
| | | | | | (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.
* Remove 576 references of include files that were not needed.Bruce Momjian2006-07-14
|
* Allow include files to compile own their own.Bruce Momjian2006-07-13
| | | | | | | Strip unused include files out unused include files, and add needed includes to C files. The next step is to remove unused include files in C files.
* Fix EXPLAIN so that it can drill down through multiple levels of subplanTom Lane2006-04-08
| | | | | | | | | when trying to locate the referent of a RECORD variable. This fixes the 'record type has not been registered' failure reported by Stefan Kaltenbrunner about a month ago. A side effect of the way I chose to fix it is that most variable references in join conditions will now be properly labeled with the variable's source table name, instead of the not-too-helpful 'outer' or 'inner' we used to use.
* Update copyright for 2006. Update scripts.Bruce Momjian2006-03-05
|
* Attached is a patch that replaces a bunch of places where StringInfosNeil Conway2006-03-01
| | | | | | | | | | | | | are unnecessarily allocated on the heap rather than the stack. If the StringInfo doesn't outlive the stack frame in which it is created, there is no need to allocate it on the heap via makeStringInfo() -- stack allocation is faster. While it's not a big deal unless the code is in a critical path, I don't see a reason not to save a few cycles -- using stack allocation is not less readable. I also cleaned up a bit of code along the way: moved variable declarations into a more tightly-enclosing scope where possible, fixed some pointless copying of strings in dblink, etc.
* Extend the ExecInitNode API so that plan nodes receive a set of flagTom Lane2006-02-28
| | | | | | | | | | | | bits indicating which optional capabilities can actually be exercised at runtime. This will allow Sort and Material nodes, and perhaps later other nodes, to avoid unnecessary overhead in common cases. This commit just adds the infrastructure and arranges to pass the correct flag values down to plan nodes; none of the actual optimizations are here yet. I'm committing this separately in case anyone wants to measure the added overhead. (It should be negligible.) Simon Riggs and Tom Lane
* Improve my initial, rather hacky implementation of joins to appendTom Lane2006-02-05
| | | | | | | | relations: fix the executor so that we can have an Append plan on the inside of a nestloop and still pass down outer index keys to index scans within the Append, then generate such plans as if they were regular inner indexscans. This avoids the need to evaluate the outer relation multiple times.
* Fix EXPLAIN and EXECUTE commands to pass portal parameters through toTom Lane2005-11-29
| | | | | the executor. This allows, for example, JDBC clients to use '?' bound parameters in these commands. Per gripe from Virag Saksena.
* Teach tid-scan code to make use of "ctid = ANY (array)" clauses, so thatTom Lane2005-11-26
| | | | | | | "ctid IN (list)" will still work after we convert IN to ScalarArrayOpExpr. Make some minor efficiency improvements while at it, such as ensuring that multiple TIDs are fetched in physical heap order. And fix EXPLAIN so that it shows what's really going on for a TID scan.
* Re-run pgindent, fixing a problem where comment lines after a blankBruce Momjian2005-11-22
| | | | | | | | | comment line where output as too long, and update typedefs for /lib directory. Also fix case where identifiers were used as variable names in the backend, but as typedefs in ecpg (favor the backend for indenting). Backpatch to 8.1.X.
* Fix EXPLAIN ANALYZE bug noted by Wiebe Cazemier: although we wereTom Lane2005-10-21
| | | | | | | | | | | properly advancing the CommandCounter between multiple sub-queries generated by rules, we forgot to update the snapshot being used, so that the successive sub-queries didn't actually see each others' results. This is still not *exactly* like the semantics of normal execution of the same queries, in that we don't take new transaction snapshots and hence don't see changes from concurrently committed commands, but I think that's OK and probably even preferable for EXPLAIN ANALYZE.
* Standard pgindent run for 8.1.Bruce Momjian2005-10-15
|
* Remove unused 'printCost' field from ExplainState, and simplify the codeNeil Conway2005-06-04
| | | | | accordingly (this field was always initialized to true). Patch from Alvaro Herrera.
* Revise handling of dropped columns in JOIN alias lists to avoid aTom Lane2005-06-03
| | | | | | | | | | | | | | | | | | | | | performance problem pointed out by phil@vodafone: to wit, we were spending O(N^2) time to check dropped-ness in an N-deep join tree, even in the case where the tree was freshly constructed and couldn't possibly mention any dropped columns. Instead of recursing in get_rte_attribute_is_dropped(), change the data structure definition: the joinaliasvars list of a JOIN RTE must have a NULL Const instead of a Var at any position that references a now-dropped column. This costs nothing during normal parse-rewrite-plan path, and instead we have a linear-time update to make when loading a stored rule that might contain now-dropped columns. While at it, move the responsibility for acquring locks on relations referenced by rules into this separate function (which I therefore chose to call AcquireRewriteLocks). This saves effort --- namely, duplicated lock grabs in parser and rewriter --- in the normal path at a cost of one extra non-locked heap_open() in the stored-rule path; seems a good tradeoff. A fringe benefit is that it is now *much* clearer that we acquire lock on relations referenced in rules before we make any rewriter decisions based on their properties. (I don't know of any bug of that ilk, but it wasn't exactly clear before.)
* Remove support for OR'd indexscans internal to a single IndexScan planTom Lane2005-04-25
| | | | | | | | node, as this behavior is now better done as a bitmap OR indexscan. This allows considerable simplification in nodeIndexscan.c itself as well as several planner modules concerned with indexscan plan generation. Also we can improve the sharing of code between regular and bitmap indexscans, since they are now working with nigh-identical Plan nodes.
* First cut at planner support for bitmap index scans. Lots to do yet,Tom Lane2005-04-22
| | | | | | | | but the code is basically working. Along the way, rewrite the entire approach to processing OR index conditions, and make it work in join cases for the first time ever. orindxpath.c is now basically obsolete, but I left it in for the time being to allow easy comparison testing against the old implementation.
* Create executor and planner-backend support for decoupled heap and indexTom Lane2005-04-19
| | | | | | | | | scans, using in-memory tuple ID bitmaps as the intermediary. The planner frontend (path creation and cost estimation) is not there yet, so none of this code can be executed. I have tested it using some hacked planner code that is far too ugly to see the light of day, however. Committing now so that the bulk of the infrastructure changes go in before the tree drifts under me.