Re: Problem reloading regression database

[2002-01-13 15:17] Tom Lane said:
| Brent Verner <brent(at)rcfile(dot)org> writes:
| > I fixed this by making an int* mapping from specified collist
| > position to actual rd_att->attrs position.
|
| Sounds better.
|
| > I'm still a bit^W^W lost as hell on how the column default magic
| > happens.
|
| I'd say use build_column_default() in src/backend/optimizer/prep/preptlist.c
| to set up a default expression (possibly just NULL) for every column
| that's not supplied by the input. That routine's not exported now, but
| it could be, or perhaps it should be moved somewhere else. (Suggestions
| anyone? Someplace in src/backend/catalog might be a more appropriate
| place for it.)

gotcha.

| Then in the per-tuple loop you use ExecEvalExpr, or more likely
| ExecEvalExprSwitchContext, to execute the default expressions.
| The econtext wanted by ExecEvalExpr can be had from the estate
| that CopyFrom already creates; use GetPerTupleExprContext(estate).

many, many thanks!

| You'll need to verify that you have got the memory context business
| right, ie, no memory leak across rows. I think the above sketch is
| sufficient, but check it with a memory-eating default expression
| evaluated for a few million input rows ...

Yes, the above info should get me through.

| and you are doing your
| testing with --enable-cassert, I trust, to catch any dangling pointers.

<ducks>
I am now :-o

thank you.
brent

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