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* JIT tuple deforming in LLVM JIT provider.Andres Freund2018-03-26
| | | | | | | | | | | | | | | | | | | | | Performing JIT compilation for deforming gains performance benefits over unJITed deforming from compile-time knowledge of the tuple descriptor. Fixed column widths, NOT NULLness, etc can be taken advantage of. Right now the JITed deforming is only used when deforming tuples as part of expression evaluation (and obviously only if the descriptor is known). It's likely to be beneficial in other cases, too. By default tuple deforming is JITed whenever an expression is JIT compiled. There's a separate boolean GUC controlling it, but that's expected to be primarily useful for development and benchmarking. Docs will follow in a later commit containing docs for the whole JIT feature. Author: Andres Freund Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
* Add expression compilation support to LLVM JIT provider.Andres Freund2018-03-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In addition to the interpretation of expressions (which back evaluation of WHERE clauses, target list projection, aggregates transition values etc) support compiling expressions to native code, using the infrastructure added in earlier commits. To avoid duplicating a lot of code, only support emitting code for cases that are likely to be performance critical. For expression steps that aren't deemed that, use the existing interpreter. The generated code isn't great - some architectural changes are required to address that. But this already yields a significant speedup for some analytics queries, particularly with WHERE clauses filtering a lot, or computing multiple aggregates. Author: Andres Freund Tested-By: Thomas Munro Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de Disable JITing for VALUES() nodes. VALUES() nodes are only ever executed once. This is primarily helpful for debugging, when forcing JITing even for cheap queries. Author: Andres Freund Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
* Allow tupleslots to have a fixed tupledesc, use in executor nodes.Andres Freund2018-02-16
| | | | | | | | | | | | | | | | | | | | | The reason for doing so is that it will allow expression evaluation to optimize based on the underlying tupledesc. In particular it will allow to JIT tuple deforming together with the expression itself. For that expression initialization needs to be moved after the relevant slots are initialized - mostly unproblematic, except in the case of nodeWorktablescan.c. After doing so there's no need for ExecAssignResultType() and ExecAssignResultTypeFromTL() anymore, as all former callers have been converted to create a slot with a fixed descriptor. When creating a slot with a fixed descriptor, tts_values/isnull can be allocated together with the main slot, reducing allocation overhead and increasing cache density a bit. Author: Andres Freund Discussion: https://postgr.es/m/20171206093717.vqdxe5icqttpxs3p@alap3.anarazel.de
* Do execGrouping.c via expression eval machinery, take two.Andres Freund2018-02-16
| | | | | | | | | | | | | This has a performance benefit on own, although not hugely so. The primary benefit is that it will allow for to JIT tuple deforming and comparator invocations. Large parts of this were previously committed (773aec7aa), but the commit contained an omission around cross-type comparisons and was thus reverted. Author: Andres Freund Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de
* Revert "Do execGrouping.c via expression eval machinery."Andres Freund2018-02-15
| | | | | | | | | | | | | | | This reverts commit 773aec7aa98abd38d6d9435913bb8e14e392c274. There's an unresolved issue in the reverted commit: It only creates one comparator function, but in for the nodeSubplan.c case we need more (c.f. FindTupleHashEntry vs LookupTupleHashEntry calls in nodeSubplan.c). This isn't too difficult to fix, but it's not entirely trivial either. The fact that the issue only causes breakage on 32bit systems shows that the current test coverage isn't that great. To avoid turning half the buildfarm red till those two issues are addressed, revert.
* Do execGrouping.c via expression eval machinery.Andres Freund2018-02-15
| | | | | | | | | This has a performance benefit on own, although not hugely so. The primary benefit is that it will allow for to JIT tuple deforming and comparator invocations. Author: Andres Freund Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de
* Initialize unused ExprEvalStep fields.Andres Freund2018-01-29
| | | | | | | | | | ExecPushExprSlots didn't initialize ExprEvalStep's resvalue/resnull steps as it didn't use them. That caused wrong valgrind warnings for an upcoming patch, so zero-intialize. Also zero-initialize all scratch ExprEvalStep's allocated on the stack, to avoid issues with similar future omissions of non-critial data.
* Replace AclObjectKind with ObjectTypePeter Eisentraut2018-01-19
| | | | | | | | | AclObjectKind was basically just another enumeration for object types, and we already have a preferred one for that. It's only used in aclcheck_error. By using ObjectType instead, we can also give some more precise error messages, for example "index" instead of "relation". Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
* Expression evaluation based aggregate transition invocation.Andres Freund2018-01-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously aggregate transition and combination functions were invoked by special case code in nodeAgg.c, evaluating input and filters separately using the expression evaluation machinery. That turns out to not be great for performance for several reasons: - repeated expression evaluations have some cost - the transition functions invocations are poorly predicted, as commonly there are multiple aggregates in a query, resulting in the same call-stack invoking different functions. - filter and input computation had to be done separately - the special case code made it hard to implement JITing of the whole transition function invocation Address this by building one large expression that computes input, evaluates filters, and invokes transition functions. This leads to moderate speedups in queries bottlenecked by aggregate computations, and enables large speedups for similar cases once JITing is done. There's potential for further improvement: - It'd be nice if we could simplify the somewhat expensive aggstate->all_pergroups lookups. - right now there's still an advance_transition_function invocation in nodeAgg.c, leading to some code duplication. Author: Andres Freund Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Perform slot validity checks in a separate pass over expression.Andres Freund2017-12-29
| | | | | | | | | | | | | | This reduces code duplication a bit, but the primary benefit that it makes JITing expression evaluation easier. When doing so we can't, as previously done in the interpreted case, really change opcode without recompiling. Nor dow we just carry around unnecessary branches to avoid re-checking over and over. As a minor side-effect this makes ExecEvalStepOp() O(log(N)) rather than O(N). Author: Andres Freund Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
* Rearrange execution of PARAM_EXTERN Params for plpgsql's benefit.Tom Lane2017-12-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does three interrelated things: * Create a new expression execution step type EEOP_PARAM_CALLBACK and add the infrastructure needed for add-on modules to generate that. As discussed, the best control mechanism for that seems to be to add another hook function to ParamListInfo, which will be called by ExecInitExpr if it's supplied and a PARAM_EXTERN Param is found. For stand-alone expressions, we add a new entry point to allow the ParamListInfo to be specified directly, since it can't be retrieved from the parent plan node's EState. * Redesign the API for the ParamListInfo paramFetch hook so that the ParamExternData array can be entirely virtual. This also lets us get rid of ParamListInfo.paramMask, instead leaving it to the paramFetch hook to decide which param IDs should be accessible or not. plpgsql_param_fetch was already doing the identical masking check, so having callers do it too seemed redundant. While I was at it, I added a "speculative" flag to paramFetch that the planner can specify as TRUE to avoid unwanted failures. This solves an ancient problem for plpgsql that it couldn't provide values of non-DTYPE_VAR variables to the planner for fear of triggering premature "record not assigned yet" or "field not found" errors during planning. * Rework plpgsql to get rid of the need for "unshared" parameter lists, by dint of turning the single ParamListInfo per estate into a nearly read-only data structure that doesn't instantiate any per-variable data. Instead, the paramFetch hook controls access to per-variable data and can make the right decisions on the fly, replacing the cases that we used to need multiple ParamListInfos for. This might perhaps have been a performance loss on its own, but by using a paramCompile hook we can bypass plpgsql_param_fetch entirely during normal query execution. (It's now only called when, eg, we copy the ParamListInfo into a cursor portal. copyParamList() or SerializeParamList() effectively instantiate the virtual parameter array as a simple physical array without a paramFetch hook, which is what we want in those cases.) This allows reverting most of commit 6c82d8d1f, though I kept the cosmetic code-consolidation aspects of that (eg the assign_simple_var function). Performance testing shows this to be at worst a break-even change, and it can provide wins ranging up to 20% in test cases involving accesses to fields of "record" variables. The fact that values of such variables can now be exposed to the planner might produce wins in some situations, too, but I've not pursued that angle. In passing, remove the "parent" pointer from the arguments to ExecInitExprRec and related functions, instead storing that pointer in a transient field in ExprState. The ParamListInfo pointer for a stand-alone expression is handled the same way; we'd otherwise have had to add yet another recursively-passed-down argument in expression compilation. Discussion: https://postgr.es/m/32589.1513706441@sss.pgh.pa.us
* Support arrays over domains.Tom Lane2017-09-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allowing arrays with a domain type as their element type was left un-done in the original domain patch, but not for any very good reason. This omission leads to such surprising results as array_agg() not working on a domain column, because the parser can't identify a suitable output type for the polymorphic aggregate. In order to fix this, first clean up the APIs of coerce_to_domain() and some internal functions in parse_coerce.c so that we consistently pass around a CoercionContext along with CoercionForm. Previously, we sometimes passed an "isExplicit" boolean flag instead, which is strictly less information; and coerce_to_domain() didn't even get that, but instead had to reverse-engineer isExplicit from CoercionForm. That's contrary to the documentation in primnodes.h that says that CoercionForm only affects display and not semantics. I don't think this change fixes any live bugs, but it makes things more consistent. The main reason for doing it though is that now build_coercion_expression() receives ccontext, which it needs in order to be able to recursively invoke coerce_to_target_type(). Next, reimplement ArrayCoerceExpr so that the node does not directly know any details of what has to be done to the individual array elements while performing the array coercion. Instead, the per-element processing is represented by a sub-expression whose input is a source array element and whose output is a target array element. This simplifies life in parse_coerce.c, because it can build that sub-expression by a recursive invocation of coerce_to_target_type(). The executor now handles the per-element processing as a compiled expression instead of hard-wired code. The main advantage of this is that we can use a single ArrayCoerceExpr to handle as many as three successive steps per element: base type conversion, typmod coercion, and domain constraint checking. The old code used two stacked ArrayCoerceExprs to handle type + typmod coercion, which was pretty inefficient, and adding yet another array deconstruction to do domain constraint checking seemed very unappetizing. In the case where we just need a single, very simple coercion function, doing this straightforwardly leads to a noticeable increase in the per-array-element runtime cost. Hence, add an additional shortcut evalfunc in execExprInterp.c that skips unnecessary overhead for that specific form of expression. The runtime speed of simple cases is within 1% or so of where it was before, while cases that previously required two levels of array processing are significantly faster. Finally, create an implicit array type for every domain type, as we do for base types, enums, etc. Everything except the array-coercion case seems to just work without further effort. Tom Lane, reviewed by Andrew Dunstan Discussion: https://postgr.es/m/9852.1499791473@sss.pgh.pa.us
* Change tupledesc->attrs[n] to TupleDescAttr(tupledesc, n).Andres Freund2017-08-20
| | | | | | | | | | | This is a mechanical change in preparation for a later commit that will change the layout of TupleDesc. Introducing a macro to abstract the details of where attributes are stored will allow us to change that in separate step and revise it in future. Author: Thomas Munro, editorialized by Andres Freund Reviewed-By: Andres Freund Discussion: https://postgr.es/m/CAEepm=0ZtQ-SpsgCyzzYpsXS6e=kZWqk3g5Ygn3MDV7A8dabUA@mail.gmail.com
* Be more consistent about errors for opfamily member lookup failures.Tom Lane2017-07-24
| | | | | | | | | | | | | | | Add error checks in some places that were calling get_opfamily_member or get_opfamily_proc and just assuming that the call could never fail. Also, standardize the wording for such errors in some other places. None of these errors are expected in normal use, hence they're just elog not ereport. But they may be handy for diagnosing omissions in custom opclasses. Rushabh Lathia found the oversight in RelationBuildPartitionKey(); I found the others by grepping for all callers of these functions. Discussion: https://postgr.es/m/CAGPqQf2R9Nk8htpv0FFi+FP776EwMyGuORpc9zYkZKC8sFQE3g@mail.gmail.com
* Improve comments for execExpr.c's handling of FieldStore subexpressions.Tom Lane2017-07-15
| | | | | | | | Given this code's general eagerness to use subexpressions' output variables as temporary workspace, it's not exactly clear that it is safe for FieldStore to tell a newval subexpression that it can write into the same variable that is being supplied as a potential input. Document the chain of assumptions needed for that to be safe.
* Improve comments for execExpr.c's isAssignmentIndirectionExpr().Tom Lane2017-07-15
| | | | | | I got confused about why this function doesn't need to recursively search the expression tree for a CaseTestExpr node. After figuring that out, add a comment to save the next person some time.
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Fix typo in commentMagnus Hagander2017-05-29
| | | | Masahiko Sawada
* Provide an error cursor for "can't call an SRF here" errors.Tom Lane2017-04-18
| | | | | | | | | | | | | | | | | | | | | | | | | Since it appears that v10 is going to move the goalposts by some amount in terms of where you can and can't invoke set-returning functions, arrange for the executor's "set-valued function called in context that cannot accept a set" errors to include a syntax position if possible, pointing to the specific SRF that can't be called where it's located. The main bit of infrastructure needed for this is to make the query source text accessible in the executor; but it turns out that commit 4c728f382 already did that. We just need a new function executor_errposition() modeled on parser_errposition(), and we're ready to rock. While experimenting with this, I noted that the error position wasn't properly reported if it occurred in a plpgsql FOR-over-query loop, which turned out to be because SPI_cursor_open_internal wasn't providing an error context callback during PortalStart. Fix that. There's a whole lot more that could be done with this infrastructure now that it's there, but this is not the right time in the development cycle for that sort of work. Hence, resist the temptation to plaster executor_errposition() calls everywhere ... for the moment. Discussion: https://postgr.es/m/5263.1492471571@sss.pgh.pa.us
* Improve castNode notation by introducing list-extraction-specific variants.Tom Lane2017-04-10
| | | | | | | | | | | | | | | | | This extends the castNode() notation introduced by commit 5bcab1114 to provide, in one step, extraction of a list cell's pointer and coercion to a concrete node type. For example, "lfirst_node(Foo, lc)" is the same as "castNode(Foo, lfirst(lc))". Almost half of the uses of castNode that have appeared so far include a list extraction call, so this is pretty widely useful, and it saves a few more keystrokes compared to the old way. As with the previous patch, back-patch the addition of these macros to pg_list.h, so that the notation will be available when back-patching. Patch by me, after an idea of Andrew Gierth's. Discussion: https://postgr.es/m/14197.1491841216@sss.pgh.pa.us
* Ensure that ExecPrepareExprList's result is all in one memory context.Tom Lane2017-04-07
| | | | | | Noted by Amit Langote. Discussion: https://postgr.es/m/aad31672-4983-d95d-d24e-6b42fee9b985@lab.ntt.co.jp
* Identity columnsPeter Eisentraut2017-04-06
| | | | | | | | | | | | | This is the SQL standard-conforming variant of PostgreSQL's serial columns. It fixes a few usability issues that serial columns have: - CREATE TABLE / LIKE copies default but refers to same sequence - cannot add/drop serialness with ALTER TABLE - dropping default does not drop sequence - need to grant separate privileges to sequence - other slight weirdnesses because serial is some kind of special macro Reviewed-by: Vitaly Burovoy <vitaly.burovoy@gmail.com>
* Remove unreachable code in expression evaluation.Andres Freund2017-03-25
| | | | | | | | | The previous code still contained expression evaluation time support for CaseExprs without a defresult. But transformCaseExpr() creates a default expression if necessary. Author: Andres Freund Discussion: https://postgr.es/m/4834.1490480275@sss.pgh.pa.us
* Faster expression evaluation and targetlist projection.Andres Freund2017-03-25
This replaces the old, recursive tree-walk based evaluation, with non-recursive, opcode dispatch based, expression evaluation. Projection is now implemented as part of expression evaluation. This both leads to significant performance improvements, and makes future just-in-time compilation of expressions easier. The speed gains primarily come from: - non-recursive implementation reduces stack usage / overhead - simple sub-expressions are implemented with a single jump, without function calls - sharing some state between different sub-expressions - reduced amount of indirect/hard to predict memory accesses by laying out operation metadata sequentially; including the avoidance of nearly all of the previously used linked lists - more code has been moved to expression initialization, avoiding constant re-checks at evaluation time Future just-in-time compilation (JIT) has become easier, as demonstrated by released patches intended to be merged in a later release, for primarily two reasons: Firstly, due to a stricter split between expression initialization and evaluation, less code has to be handled by the JIT. Secondly, due to the non-recursive nature of the generated "instructions", less performance-critical code-paths can easily be shared between interpreted and compiled evaluation. The new framework allows for significant future optimizations. E.g.: - basic infrastructure for to later reduce the per executor-startup overhead of expression evaluation, by caching state in prepared statements. That'd be helpful in OLTPish scenarios where initialization overhead is measurable. - optimizing the generated "code". A number of proposals for potential work has already been made. - optimizing the interpreter. Similarly a number of proposals have been made here too. The move of logic into the expression initialization step leads to some backward-incompatible changes: - Function permission checks are now done during expression initialization, whereas previously they were done during execution. In edge cases this can lead to errors being raised that previously wouldn't have been, e.g. a NULL array being coerced to a different array type previously didn't perform checks. - The set of domain constraints to be checked, is now evaluated once during expression initialization, previously it was re-built every time a domain check was evaluated. For normal queries this doesn't change much, but e.g. for plpgsql functions, which caches ExprStates, the old set could stick around longer. The behavior around might still change. Author: Andres Freund, with significant changes by Tom Lane, changes by Heikki Linnakangas Reviewed-By: Tom Lane, Heikki Linnakangas Discussion: https://postgr.es/m/20161206034955.bh33paeralxbtluv@alap3.anarazel.de