Обсуждение: Stored procedure array limits
I have a large stored procedure with 16 arrays, mostly varchar, each with dimension 3000. The procedure works fine on a small number of rows used from these arrays but gets the following error for large rowsets: ERROR: invalid array subscripts CONTEXT: PL/pgSQL function "name_search" line 64 at assignment I have not exceeded the size of the arrays, index-wise. I increased max_stack_depth to 32768 and work_mem to 32768 but without effect. If I comment out two particular arrays (that can have null values), it also runs OK. Anybody have any ideas? Paul
"Paul B. Anderson" <paul.a@pnlassociates.com> writes: > I have a large stored procedure with 16 arrays, mostly varchar, each > with dimension 3000. The procedure works fine on a small number of rows > used from these arrays but gets the following error for large rowsets: > ERROR: invalid array subscripts Right offhand I only see that error being thrown for out-of-range array subscripts. Are you maybe trying to fill the arrays in nonsequential order? > If I comment out two particular arrays (that can have null values), it > also runs OK. As already noted, we don't support nulls in arrays before 8.2, but I'm not exactly sure how that omission leads to this error message. regards, tom lane
I've checked my code and it does not seem to run past any limits. I am filling the arrays in sequential order, extending each one in parallel with the others.
The null problem fixed the code for some cases but I'm still having problems in general and with the same error message but reported in another place.
Paul
Tom Lane wrote:
The null problem fixed the code for some cases but I'm still having problems in general and with the same error message but reported in another place.
Paul
Tom Lane wrote:
"Paul B. Anderson" <paul.a@pnlassociates.com> writes:I have a large stored procedure with 16 arrays, mostly varchar, each with dimension 3000. The procedure works fine on a small number of rows used from these arrays but gets the following error for large rowsets:ERROR: invalid array subscriptsRight offhand I only see that error being thrown for out-of-range array subscripts. Are you maybe trying to fill the arrays in nonsequential order?If I comment out two particular arrays (that can have null values), it also runs OK.As already noted, we don't support nulls in arrays before 8.2, but I'm not exactly sure how that omission leads to this error message. regards, tom lane .
Actually, I was not filling all of the arrays in sequential order. I added code to initialize them in order and the function seems to be working now. Is that a known problem?
Paul
Paul B. Anderson wrote:
Paul
Paul B. Anderson wrote:
I've checked my code and it does not seem to run past any limits. I am filling the arrays in sequential order, extending each one in parallel with the others.
The null problem fixed the code for some cases but I'm still having problems in general and with the same error message but reported in another place.
Paul
Tom Lane wrote:"Paul B. Anderson" <paul.a@pnlassociates.com> writes:I have a large stored procedure with 16 arrays, mostly varchar, each with dimension 3000. The procedure works fine on a small number of rows used from these arrays but gets the following error for large rowsets:ERROR: invalid array subscriptsRight offhand I only see that error being thrown for out-of-range array subscripts. Are you maybe trying to fill the arrays in nonsequential order?If I comment out two particular arrays (that can have null values), it also runs OK.As already noted, we don't support nulls in arrays before 8.2, but I'm not exactly sure how that omission leads to this error message. regards, tom lane .
[ expanding this thread, as it now needs wider discussion ] "Paul B. Anderson" <paul.a@pnlassociates.com> writes: > Actually, I was not filling all of the arrays in sequential order. I > added code to initialize them in order and the function seems to be > working now. Is that a known problem? Well, it's a documented behavior: section 8.10.4 saith A stored array value can be enlarged by assigning to an element adjacent to those already present, or by assigning to a slice that is adjacent to or overlaps the data already present. Up to 8.2 we didn't have a lot of choice about this, because without any ability to have nulls embedded in arrays, there wasn't any sane thing to do with the intermediate positions if you assigned to an element not adjacent to the existing range. As of 8.2 we could allow assignment to arbitrary positions by filling the intermediate positions with nulls. The code hasn't actually been changed to allow that, but it's something we could consider doing now. Comments? regards, tom lane
Re: [GENERAL] Array assignment behavior (was Re: Stored procedure array limits)
От
Casey Duncan
Дата:
On Sep 29, 2006, at 9:14 AM, Tom Lane wrote: > [ expanding this thread, as it now needs wider discussion ] > > "Paul B. Anderson" <paul.a@pnlassociates.com> writes: >> Actually, I was not filling all of the arrays in sequential order. I >> added code to initialize them in order and the function seems to be >> working now. Is that a known problem? > > Well, it's a documented behavior: section 8.10.4 saith > > A stored array value can be enlarged by assigning to an element > adjacent to those already present, or by assigning to a slice > that is adjacent to or overlaps the data already present. > > Up to 8.2 we didn't have a lot of choice about this, because > without any > ability to have nulls embedded in arrays, there wasn't any sane > thing to > do with the intermediate positions if you assigned to an element not > adjacent to the existing range. As of 8.2 we could allow > assignment to > arbitrary positions by filling the intermediate positions with nulls. > The code hasn't actually been changed to allow that, but it's > something > we could consider doing now. > > Comments? At first blush, this strikes me as a bit too magical/implicit. Are there other languages where sequences behave similarly? The best analogy that comes to mind is sparse files, but in that case there is an implicit contract that the intervening empty regions do not actually occupy physical space, doesn't sound like that's true here. I think the result of this change would be more difficult debugging of off-by-one errors and their ilk, rather than actually being a real benefit. OTOH, perhaps there is a real use-case I am missing here. I don't see the rest of this thread on GENERAL and I couldn't find it searching the archives, where did it come from? -Casey
Re: [GENERAL] Array assignment behavior (was Re: Stored procedure array limits)
От
"John D. Burger"
Дата:
>> As of 8.2 we could allow assignment to >> arbitrary positions by filling the intermediate positions with nulls. >> The code hasn't actually been changed to allow that, but it's >> something >> we could consider doing now. > > At first blush, this strikes me as a bit too magical/implicit. Are > there other languages where sequences behave similarly? > perl -e '@A = (1, 2, 3); print "@A\n"; $A[10] = 10; print "@A\n";' 1 2 3 1 2 3 10 - John D. Burger MITRE
It seems that the suggestion to fill intermediate positions with NULLs would be preferable to the current behavior.
I know of no requirement to populate arrays in sequence in any other language so I think other programmers would be surprised too by the current behavior.
Paul
Tom Lane wrote:
I know of no requirement to populate arrays in sequence in any other language so I think other programmers would be surprised too by the current behavior.
Paul
Tom Lane wrote:
[ expanding this thread, as it now needs wider discussion ] "Paul B. Anderson" <paul.a@pnlassociates.com> writes:Actually, I was not filling all of the arrays in sequential order. I added code to initialize them in order and the function seems to be working now. Is that a known problem?Well, it's a documented behavior: section 8.10.4 saith A stored array value can be enlarged by assigning to an elementadjacent to those already present, or by assigning to a slicethat is adjacent to or overlaps the data already present. Up to 8.2 we didn't have a lot of choice about this, because without any ability to have nulls embedded in arrays, there wasn't any sane thing to do with the intermediate positions if you assigned to an element not adjacent to the existing range. As of 8.2 we could allow assignment to arbitrary positions by filling the intermediate positions with nulls. The code hasn't actually been changed to allow that, but it's something we could consider doing now. Comments? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match .
Yep, that definitely threw me the first time I encountered it. Paul B. Anderson wrote: > It seems that the suggestion to fill intermediate positions with NULLs > would be preferable to the current behavior. > > I know of no requirement to populate arrays in sequence in any other > language so I think other programmers would be surprised too by the > current behavior. > > Paul > > > Tom Lane wrote: >> [ expanding this thread, as it now needs wider discussion ] >> >> "Paul B. Anderson" <paul.a@pnlassociates.com> writes: >> >>> Actually, I was not filling all of the arrays in sequential order. I >>> added code to initialize them in order and the function seems to be >>> working now. Is that a known problem? >>> >> >> Well, it's a documented behavior: section 8.10.4 saith >> >> A stored array value can be enlarged by assigning to an element >> adjacent to those already present, or by assigning to a slice >> that is adjacent to or overlaps the data already present. >> >> Up to 8.2 we didn't have a lot of choice about this, because without any >> ability to have nulls embedded in arrays, there wasn't any sane thing to >> do with the intermediate positions if you assigned to an element not >> adjacent to the existing range. As of 8.2 we could allow assignment to >> arbitrary positions by filling the intermediate positions with nulls. >> The code hasn't actually been changed to allow that, but it's something >> we could consider doing now. >> >> Comments? >> >> regards, tom lane >> >> ---------------------------(end of broadcast)--------------------------- >> TIP 9: In versions below 8.0, the planner will ignore your desire to >> choose an index scan if your joining column's datatypes do not >> match >> >> . >> >> -- erik jones <erik@myemma.com> software development emma(r)
"John D. Burger" <john@mitre.org> writes: >>> As of 8.2 we could allow assignment to >>> arbitrary positions by filling the intermediate positions with nulls. >>> The code hasn't actually been changed to allow that, but it's >>> something we could consider doing now. >> >> At first blush, this strikes me as a bit too magical/implicit. Are >> there other languages where sequences behave similarly? >>> perl -e '@A = (1, 2, 3); print "@A\n"; $A[10] = 10; print "@A\n";' > 1 2 3 > 1 2 3 10 Actually, now that I look closely, I think the SQL spec demands exactly this. Recall that SQL99 only allows one-dimensional, lower-bound-one arrays. The specification for UPDATE ... SET C[I] = SV ... reads Case: i) If the value of C is null, then an exception condition is raised: data exception - null value in array target. ii) Otherwise: 1) Let N be the maximum cardinality of C. 2) Let M be the cardinality of the value of C. 3) Let I be the value of the <simple value specification> immediately contained in <update target>. 4) Let EDT be the element type of C. 5) Case: A) If I is greater than zero and less than or equal to M, then the value of C is replaced by an array A with element type EDT and cardinality M derived as follows: I) For j varying from 1 (one) to I-1 and from I+1 to M, the j-th element in A is the value of the j-th element in C. II) The I-th element of A is set to the specified update value, denoted by SV, by applying the General Rules of Subclause 9.2, "Store assignment", to the I-th element of A and SV as TARGET and VALUE, respectively. B) If I is greater than M and less than or equal to N, then the value of C is replaced by an array A with element type EDT and cardinality I derived as follows: I) For j varying from 1 (one) to M, the j-th element in A is the value of the j-th element in C. II) For j varying from M+1 to I-1, the j-th element in A is the null value. III) The I-th element of A is set to the specified update value, denoted by SV, by applying the General Rules of Subclause 9.2, "Store assignment", to the I-th element of A and SV as TARGET and VALUE, respectively. C) Otherwise, an exception condition is raised: data exception - array element error. We currently violate case i by allowing the null array value to be replaced by a single-element array. I'm disinclined to change that, as I think our behavior is more useful than the spec's. But case ii.5.B pretty clearly describes null-fill, so I think we'd better do that, now that we can. regards, tom lane
Ok, just so I can be sure I understand what I just read: i. says that you can assign to an array that has not been initialized. ii. states that the index of an insertion into an array should not be limited by the current range of index values of the array and requires any gaps in the index range to be set with values of null. I really don't have anything to add to discussion other than that I agree with Tom's assessment, but rather want clarify what might be a slightly hazy interpretation of the specs listed below. Tom Lane wrote: > Actually, now that I look closely, I think the SQL spec demands exactly > this. Recall that SQL99 only allows one-dimensional, lower-bound-one > arrays. The specification for UPDATE ... SET C[I] = SV ... reads > > Case: > > i) If the value of C is null, then an exception condition is > raised: data exception - null value in array target. > > ii) Otherwise: > > 1) Let N be the maximum cardinality of C. > > 2) Let M be the cardinality of the value of C. > > 3) Let I be the value of the <simple value specification> > immediately contained in <update target>. > > 4) Let EDT be the element type of C. > > 5) Case: > > A) If I is greater than zero and less than or equal to > M, then the value of C is replaced by an array A > with element type EDT and cardinality M derived as > follows: > > I) For j varying from 1 (one) to I-1 and from I+1 to > M, the j-th element in A is the value of the j-th > element in C. > > II) The I-th element of A is set to the specified > update value, denoted by SV, by applying the > General Rules of Subclause 9.2, "Store assignment", > to the I-th element of A and SV as TARGET and > VALUE, respectively. > > B) If I is greater than M and less than or equal to > N, then the value of C is replaced by an array A > with element type EDT and cardinality I derived as > follows: > > I) For j varying from 1 (one) to M, the j-th element > in A is the value of the j-th element in C. > > II) For j varying from M+1 to I-1, the j-th element in > A is the null value. > > III) The I-th element of A is set to the specified > update value, denoted by SV, by applying the > General Rules of Subclause 9.2, "Store assignment", > to the I-th element of A and SV as TARGET and > VALUE, respectively. > > C) Otherwise, an exception condition is raised: data > exception - array element error. > > We currently violate case i by allowing the null array value to be > replaced by a single-element array. I'm disinclined to change that, > as I think our behavior is more useful than the spec's. But case ii.5.B > pretty clearly describes null-fill, so I think we'd better do that, now > that we can. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 5: don't forget to increase your free space map settings > -- erik jones <erik@myemma.com> software development emma(r)