From 4c0fc077155cc688770cc77724a09d7d0129cae2 Mon Sep 17 00:00:00 2001 From: Daniel Gustafsson Date: Thu, 4 Jul 2024 16:55:52 +0200 Subject: [PATCH v3 1/2] Replace EEOP_DONE with special steps for return/no return Knowing when the side-effects of an expression is the intended result of the execution, rather than the returnvalue, is important for being able generate more efficient JITed code. This replaces EEOP_DONE with two new steps: EEOP_DONE_RETURN and EEOP_DONE_NO_RETURN. Expressions which return a value should use the former step; expressions used for their side-effects which don't return value should use the latter. Author: Andres Freund, Daniel Gustafsson Reviewed-by: Andreas Karlsson Discussion: https://postgr.es/m/415721CE-7D2E-4B74-B5D9-1950083BA03E@yesql.se Discussion: https://postgr.es/m/20191023163849.sosqbfs5yenocez3@alap3.anarazel.de --- src/backend/executor/README | 11 ++++-- src/backend/executor/execExpr.c | 22 ++++++------ src/backend/executor/execExprInterp.c | 25 ++++++++----- src/backend/executor/nodeAgg.c | 7 ++-- src/backend/jit/llvm/llvmjit_expr.c | 6 +++- src/include/executor/execExpr.h | 7 ++-- src/include/executor/executor.h | 52 +++++++++++++++++++++++++-- 7 files changed, 97 insertions(+), 33 deletions(-) diff --git a/src/backend/executor/README b/src/backend/executor/README index 642d63be61..54f4782f31 100644 --- a/src/backend/executor/README +++ b/src/backend/executor/README @@ -133,9 +133,14 @@ is used by the function evaluation step, thus avoiding extra work to copy the result values around. The last entry in a completed ExprState->steps array is always an -EEOP_DONE step; this removes the need to test for end-of-array while -iterating. Also, if the expression contains any variable references (to -user columns of the ExprContext's INNER, OUTER, or SCAN tuples), the steps +EEOP_DONE_RETURN or EEOP_DONE_NO_RETURN step; this removes the need to +test for end-of-array while iterating. The former is used when the +expression returns a value directly, the latter when side-effects of +expression initialization are the goal (e.g. for projection or +aggregate transition value computation). + +Also, if the expression contains any variable references (to user +columns of the ExprContext's INNER, OUTER, or SCAN tuples), the steps array begins with EEOP_*_FETCHSOME steps that ensure that the relevant tuples have been deconstructed to make the required columns directly available (cf. slot_getsomeattrs()). This allows individual Var-fetching diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c index c8077aa57b..5351f6a81f 100644 --- a/src/backend/executor/execExpr.c +++ b/src/backend/executor/execExpr.c @@ -8,7 +8,7 @@ * using ExecInitExpr() et al. This converts the tree into a flat array * of ExprEvalSteps, which may be thought of as instructions in a program. * At runtime, we'll execute steps, starting with the first, until we reach - * an EEOP_DONE opcode. + * an EEOP_DONE_{RETURN|NO_RETURN} opcode. * * This file contains the "compilation" logic. It is independent of the * specific execution technology we use (switch statement, computed goto, @@ -157,7 +157,7 @@ ExecInitExpr(Expr *node, PlanState *parent) ExecInitExprRec(node, state, &state->resvalue, &state->resnull); /* Finally, append a DONE step */ - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -194,7 +194,7 @@ ExecInitExprWithParams(Expr *node, ParamListInfo ext_params) ExecInitExprRec(node, state, &state->resvalue, &state->resnull); /* Finally, append a DONE step */ - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -286,7 +286,7 @@ ExecInitQual(List *qual, PlanState *parent) * have yielded TRUE, and since its result is stored in the desired output * location, we're done. */ - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -481,7 +481,7 @@ ExecBuildProjectionInfo(List *targetList, } } - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_NO_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -720,7 +720,7 @@ ExecBuildUpdateProjection(List *targetList, } } - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_NO_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -1656,7 +1656,7 @@ ExecInitExprRec(Expr *node, ExprState *state, else { /* Not trivial, so append a DONE step */ - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(elemstate, &scratch); /* and ready the subexpression */ ExecReadyExpr(elemstate); @@ -3850,7 +3850,7 @@ ExecBuildAggTrans(AggState *aggstate, AggStatePerPhase phase, scratch.resvalue = NULL; scratch.resnull = NULL; - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_NO_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -4102,7 +4102,7 @@ ExecBuildHash32Expr(TupleDesc desc, const TupleTableSlotOps *ops, scratch.resvalue = NULL; scratch.resnull = NULL; - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -4255,7 +4255,7 @@ ExecBuildGroupingEqual(TupleDesc ldesc, TupleDesc rdesc, scratch.resvalue = NULL; scratch.resnull = NULL; - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); @@ -4389,7 +4389,7 @@ ExecBuildParamSetEqual(TupleDesc desc, scratch.resvalue = NULL; scratch.resnull = NULL; - scratch.opcode = EEOP_DONE; + scratch.opcode = EEOP_DONE_RETURN; ExprEvalPushStep(state, &scratch); ExecReadyExpr(state); diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c index 9fd988cc99..5cabf41341 100644 --- a/src/backend/executor/execExprInterp.c +++ b/src/backend/executor/execExprInterp.c @@ -240,7 +240,8 @@ ExecReadyInterpretedExpr(ExprState *state) /* Simple validity checks on expression */ Assert(state->steps_len >= 1); - Assert(state->steps[state->steps_len - 1].opcode == EEOP_DONE); + Assert(state->steps[state->steps_len - 1].opcode == EEOP_DONE_RETURN || + state->steps[state->steps_len - 1].opcode == EEOP_DONE_NO_RETURN); /* * Don't perform redundant initialization. This is unreachable in current @@ -406,7 +407,8 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull) */ #if defined(EEO_USE_COMPUTED_GOTO) static const void *const dispatch_table[] = { - &&CASE_EEOP_DONE, + &&CASE_EEOP_DONE_RETURN, + &&CASE_EEOP_DONE_NO_RETURN, &&CASE_EEOP_INNER_FETCHSOME, &&CASE_EEOP_OUTER_FETCHSOME, &&CASE_EEOP_SCAN_FETCHSOME, @@ -536,9 +538,16 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull) EEO_SWITCH() { - EEO_CASE(EEOP_DONE) + EEO_CASE(EEOP_DONE_RETURN) { - goto out; + *isnull = state->resnull; + return state->resvalue; + } + + EEO_CASE(EEOP_DONE_NO_RETURN) + { + Assert(isnull == NULL); + return (Datum) 0; } EEO_CASE(EEOP_INNER_FETCHSOME) @@ -2003,13 +2012,13 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull) { /* unreachable */ Assert(false); - goto out; + goto out_error; } } -out: - *isnull = state->resnull; - return state->resvalue; +out_error: + pg_unreachable(); + return (Datum) 0; } /* diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c index 53ead77ece..c8257a23d1 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -815,11 +815,8 @@ advance_transition_function(AggState *aggstate, static void advance_aggregates(AggState *aggstate) { - bool dummynull; - - ExecEvalExprSwitchContext(aggstate->phase->evaltrans, - aggstate->tmpcontext, - &dummynull); + ExecEvalExprNoReturnSwitchContext(aggstate->phase->evaltrans, + aggstate->tmpcontext); } /* diff --git a/src/backend/jit/llvm/llvmjit_expr.c b/src/backend/jit/llvm/llvmjit_expr.c index 48ccdb942a..28df6ef469 100644 --- a/src/backend/jit/llvm/llvmjit_expr.c +++ b/src/backend/jit/llvm/llvmjit_expr.c @@ -285,7 +285,7 @@ llvm_compile_expr(ExprState *state) switch (opcode) { - case EEOP_DONE: + case EEOP_DONE_RETURN: { LLVMValueRef v_tmpisnull; LLVMValueRef v_tmpvalue; @@ -299,6 +299,10 @@ llvm_compile_expr(ExprState *state) break; } + case EEOP_DONE_NO_RETURN: + LLVMBuildRet(b, l_sizet_const(0)); + break; + case EEOP_INNER_FETCHSOME: case EEOP_OUTER_FETCHSOME: case EEOP_SCAN_FETCHSOME: diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h index eec0aa699e..2abd66b972 100644 --- a/src/include/executor/execExpr.h +++ b/src/include/executor/execExpr.h @@ -65,8 +65,11 @@ typedef struct ExprEvalRowtypeCache */ typedef enum ExprEvalOp { - /* entire expression has been evaluated completely, return */ - EEOP_DONE, + /* entire expression has been evaluated, return value */ + EEOP_DONE_RETURN, + + /* entire expression has been evaluated, no return value */ + EEOP_DONE_NO_RETURN, /* apply slot_getsomeattrs on corresponding tuple slot */ EEOP_INNER_FETCHSOME, diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h index 69c3ebff00..507a32a6a2 100644 --- a/src/include/executor/executor.h +++ b/src/include/executor/executor.h @@ -349,6 +349,34 @@ ExecEvalExpr(ExprState *state, } #endif +/* + * ExecEvalExprNoReturn + * + * Like ExecEvalExpr(), but for cases where no return value is expected, + * because the side-effects of expression evaluation are what's desired. This + * is e.g. used for projection and aggregate transition computation. + + * Evaluate expression identified by "state" in the execution context + * given by "econtext". + * + * The caller should already have switched into the temporary memory context + * econtext->ecxt_per_tuple_memory. The convenience entry point + * ExecEvalExprNoReturnSwitchContext() is provided for callers who don't + * prefer to do the switch in an outer loop. + */ +#ifndef FRONTEND +static inline void +ExecEvalExprNoReturn(ExprState *state, + ExprContext *econtext) +{ + PG_USED_FOR_ASSERTS_ONLY Datum retDatum; + + retDatum = state->evalfunc(state, econtext, NULL); + + Assert(retDatum == (Datum) 0); +} +#endif + /* * ExecEvalExprSwitchContext * @@ -370,6 +398,25 @@ ExecEvalExprSwitchContext(ExprState *state, } #endif +/* + * ExecEvalExprNoReturnSwitchContext + * + * Same as ExecEvalExprNoReturn, but get into the right allocation context + * explicitly. + */ +#ifndef FRONTEND +static inline void +ExecEvalExprNoReturnSwitchContext(ExprState *state, + ExprContext *econtext) +{ + MemoryContext oldContext; + + oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory); + ExecEvalExprNoReturn(state, econtext); + MemoryContextSwitchTo(oldContext); +} +#endif + /* * ExecProject * @@ -389,7 +436,6 @@ ExecProject(ProjectionInfo *projInfo) ExprContext *econtext = projInfo->pi_exprContext; ExprState *state = &projInfo->pi_state; TupleTableSlot *slot = state->resultslot; - bool isnull; /* * Clear any former contents of the result slot. This makes it safe for @@ -397,8 +443,8 @@ ExecProject(ProjectionInfo *projInfo) */ ExecClearTuple(slot); - /* Run the expression, discarding scalar result from the last column. */ - (void) ExecEvalExprSwitchContext(state, econtext, &isnull); + /* Run the expression */ + ExecEvalExprNoReturnSwitchContext(state, econtext); /* * Successfully formed a result row. Mark the result slot as containing a -- 2.39.3 (Apple Git-146)