Subject: [HACKERS] Aggregate function patches
Here are the aggregate function patches I originally sent in last December.
They fix sum() and avg() behavior for ints and floats when NULL values are
involved.
I was waiting to resubmit these until I had a chance to write a v6.0->v6.1
database upgrade script to ensure that existing v6.0 databases which have
not been reloaded for v6.1 do no break with the new aggregate behavior.
These scripts are included below. It's OK with me if someone wants to do
something different with the upgrade strategy, but something like this
was discussed a few weeks ago.
Also, there were a couple of small items which cropped up in doing a clean
install of 970403 (actually 970402 + 970403 changes since the full 970403
tar file appears to be damaged or at least suspect). They are the first
two patches below and can be omitted if desired (although I think they
aren't dangerous :).
Subject: [HACKERS] linux/alpha patches
These patches lay the groundwork for a Linux/Alpha port. The port doesn't
actually work unless you tweak the linker to put all the pointers in the
first 32 bits of the address space, but it's at least a start. It
implements the test-and-set instruction in Alpha assembly, and also fixes
a lot of pointer-to-integer conversions, which is probably good anyway.
Subject: [HACKERS] better access control error messages
This patch replaces the 'no such class or insufficient privilege' with
distinct error messages that tell you whether the table really doesn't
exist or whether access was denied.
Changes:
* Unique index capability works using the syntax 'create unique
index'.
* Duplicate OID's in the system tables are removed. I put
little scripts called 'duplicate_oids' and 'find_oid' in
include/catalog that help to find and remove duplicate OID's.
I also moved 'unused_oids' from backend/catalog to
include/catalog, since it has to be in the same directory
as the include files in order to work.
* The backend tries converting the name of a function or aggregate
to all lowercase if the original name given doesn't work (mostly
for compatibility with ODBC).
* You can 'SELECT NULL' to your heart's content.
* I put my _bt_updateitem fix in instead, which uses
_bt_insertonpg so that even if the new key is so big that
the page has to be split, everything still works.
* All literal references to system catalog OID's have been
replaced with references to define'd constants from the catalog
header files.
* I added a couple of node copy functions. I think this was a
preliminary attempt to get rules to work.
I found another bug in btree index. Looking at the code it seems that NULL
keys are never used to build or scan a btree index (see the explain commands
in the example). However this is not the case when a null key is retrieved
in an outer loop of a join select and used in an index scan of an inner loop.
This bug causes at least three kinds of problems:
1) the backend crashes when it tries to compare a text string with a null.
2) it is not possible to find tuples with null keys in a join.
3) null is considered equal to 0 when the datum is passed by value, see
the last query.
Submitted by: Massimo Dal Zotto <dz@cs.unitn.it>
It's bug in nodeAgg.c on lines 241, 242:
null_array = malloc(nagg);
for (i=0;i<nagg;i++)
null_array[i] = 'n';
oneTuple = heap_formtuple(tupType, tupValue, null_array);
- your query has not only aggregates but also 'group by-ed' fields and so
null_array should contain tupType->natts elements (tupType->natts > nagg in
your case).
Patch follows and it's very simple.
VAdim
Bruce Momjian
Vadim B. Mikheev
Marc G. Fournier
Bryan Henderson