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Extend ExecBuildAggTrans() to support a NULL pointer check.

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Optionally push a step to check for a NULL pointer to the pergroup
state.

This will be important for disk-based hash aggregation in combination
with grouping sets. When memory limits are reached, a given tuple may
find its per-group state for some grouping sets but not others. For
the former, it advances the per-group state as normal; for the latter,
it skips evaluation and the calling code will have to spill the tuple
and reprocess it in a later batch.

Add the NULL check as a separate expression step because in some
common cases it's not needed.

Discussion: https://postgr.es/m/20200221202212.ssb2qpmdgrnx52sj%40alap3.anarazel.de
This commit is contained in:
Jeff Davis
2020-03-04 17:20:20 -08:00
parent 3ed2005ff5
commit c954d49046
6 changed files with 101 additions and 7 deletions
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39
src/backend/jit/llvm/llvmjit_expr.c
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@ -2046,6 +2046,45 @@ llvm_compile_expr(ExprState *state)
break;
}
case EEOP_AGG_PLAIN_PERGROUP_NULLCHECK:
{
int jumpnull;
LLVMValueRef v_aggstatep;
LLVMValueRef v_allpergroupsp;
LLVMValueRef v_pergroup_allaggs;
LLVMValueRef v_setoff;
jumpnull = op->d.agg_plain_pergroup_nullcheck.jumpnull;
/*
* pergroup_allaggs = aggstate->all_pergroups
* [op->d.agg_plain_pergroup_nullcheck.setoff];
*/
v_aggstatep = LLVMBuildBitCast(
b, v_parent, l_ptr(StructAggState), "");
v_allpergroupsp = l_load_struct_gep(
b, v_aggstatep,
FIELDNO_AGGSTATE_ALL_PERGROUPS,
"aggstate.all_pergroups");
v_setoff = l_int32_const(
op->d.agg_plain_pergroup_nullcheck.setoff);
v_pergroup_allaggs = l_load_gep1(
b, v_allpergroupsp, v_setoff, "");
LLVMBuildCondBr(
b,
LLVMBuildICmp(b, LLVMIntEQ,
LLVMBuildPtrToInt(
b, v_pergroup_allaggs, TypeSizeT, ""),
l_sizet_const(0), ""),
opblocks[jumpnull],
opblocks[opno + 1]);
break;
}
case EEOP_AGG_PLAIN_TRANS_INIT_STRICT_BYVAL:
case EEOP_AGG_PLAIN_TRANS_STRICT_BYVAL:
case EEOP_AGG_PLAIN_TRANS_BYVAL: