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Don't generate EEOP_*_FETCHSOME operations for slots know to be virtual.

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That avoids unnecessary work during both interpreted execution, and
JIT compiled expression evaluation. Both benefit from fewer expression
steps needing be processed, and for interpreted execution there now is
a fastpath dedicated to just fetching a value from a virtual
slot. That's e.g. beneficial for hashjoins over nodes that perform
projections, as the hashed columns are currently fetched individually.

Author: Soumyadeep Chakraborty, Andres Freund
Discussion: https://postgr.es/m/CAE-ML+9OKSN71+mHtfMD-L24oDp8dGTfaVjDU6U+j+FNAW5kRQ@mail.gmail.com
This commit is contained in:
Andres Freund
2019-09-30 16:06:16 -07:00
parent 34c9c53bb0
commit 36d22dd95b
3 changed files with 160 additions and 22 deletions
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6
src/backend/jit/llvm/llvmjit_expr.c
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@ -287,6 +287,9 @@ llvm_compile_expr(ExprState *state)
if (op->d.fetch.fixed)
tts_ops = op->d.fetch.kind;
/* step should not have been generated */
Assert(tts_ops != &TTSOpsVirtual);
if (opcode == EEOP_INNER_FETCHSOME)
v_slot = v_innerslot;
else if (opcode == EEOP_OUTER_FETCHSOME)
@ -297,9 +300,6 @@ llvm_compile_expr(ExprState *state)
/*
* Check if all required attributes are available, or
* whether deforming is required.
*
* TODO: skip nvalid check if slot is fixed and known to
* be a virtual slot.
*/
v_nvalid =
l_load_struct_gep(b, v_slot,