Bruce Momjian wrote:
> Has this been addressed?
>
>>Tom Lane wrote:
>>>The reason we could safely list_free inside transformInsertRow is that
>>>we know all its callers have just built the passed-in list and so there
>>>are no other pointers to it. That doesn't apply in the general case of
>>>grammar output.
After another look, even in this case there could be other pointers.
Starting around line 667 of analyze.c:
8<------------------ foreach(lc, selectQuery->targetList) { TargetEntry *tle = (TargetEntry *) lfirst(lc);
Expr *expr;
if (tle->resjunk) continue; if (tle->expr && (IsA(tle->expr, Const)
||IsA(tle->expr,Param)) && exprType((Node *) tle->expr) == UNKNOWNOID) expr = tle->expr;
else expr = (Expr *) makeVar(rtr->rtindex, tle->resno,
exprType((Node *) tle->expr), exprTypmod((Node *) tle->expr),
0); exprList = lappend(exprList, expr); }
/* Prepare row for assignment to target table */ exprList = transformInsertRow(pstate, exprList,
stmt->cols, icolumns, attrnos);
8<------------------
So in the UNKNOWNOID case, it wouldn't be safe to free the node after
transformation because it originates in the grammar output. The *only*
safe thing to free up would be a the input exprList itself. Not much to
be saved there.
>>>My advice is to get that low-hanging fruit
>>>in transformInsertRow and leave the other ideas for 8.3.
This one case doesn't provide that much memory savings by itself anyway.
I guess we'll just live with it until we can come up with a safe way to
free grammar output.
Joe
