Re: identity columns

On 4/3/17 14:19, Andres Freund wrote:
> Are you going to try to merge this soon, or are you pushing this to 11?

I plan to commit it this week. It was basically ready weeks ago, but
had to be adjusted after the executor changes.

>> + case T_NextValueExpr:
>> + {
>> + NextValueExpr *nve = (NextValueExpr *) node;
>> +
>> + scratch.opcode = EEOP_NEXTVALUEEXPR;
>> + scratch.d.nextvalueexpr.seqid = nve->seqid;
>> +
>> + ExprEvalPushStep(state, &scratch);
>> + break;
>> + }
>
> Hm - that's probably been answered somewhere, but why do we need a
> special expression type for this?

Because that's the way to evade the separate permission check that
nextval the function would otherwise do.

>> diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
>> index 4fbb5c1e74..5935b9ef75 100644
>> --- a/src/backend/executor/execExprInterp.c
>> +++ b/src/backend/executor/execExprInterp.c
>> @@ -60,6 +60,7 @@
>>
>> #include "access/tuptoaster.h"
>> #include "catalog/pg_type.h"
>> +#include "commands/sequence.h"
>> #include "executor/execExpr.h"
>> #include "executor/nodeSubplan.h"
>> #include "funcapi.h"
>> @@ -337,6 +338,7 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
>> &&CASE_EEOP_NULLIF,
>> &&CASE_EEOP_SQLVALUEFUNCTION,
>> &&CASE_EEOP_CURRENTOFEXPR,
>> + &&CASE_EEOP_NEXTVALUEEXPR,
>> &&CASE_EEOP_ARRAYEXPR,
>> &&CASE_EEOP_ARRAYCOERCE,
>> &&CASE_EEOP_ROW,
>> @@ -1228,6 +1230,14 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
>> EEO_NEXT();
>> }
>>
>> + EEO_CASE(EEOP_NEXTVALUEEXPR)
>> + {
>> + *op->resvalue = Int64GetDatum(nextval_internal(op->d.nextvalueexpr.seqid, false));
>> + *op->resnull = false;
>> +
>> + EEO_NEXT();
>> + }
>
> Is it guaranteed that the caller expects an int64? I saw that
> nextvalueexpr's have a typeid field.

It expects one of the integer types. We could cast the result of
Int64GetDatum() to the appropriate type, but that wouldn't actually do
anything.

--
Peter Eisentraut http://www.2ndQuadrant.com/
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