management. The paper clearly describes many of the ideas embodied in
our current hashing code, but as far as I could find out there is not
a direct code heritage. (Mike Olsen recalls discussion of this paper
at Postgres meetings but believes it "informed the Postgres implementation
probably just at the design level". Margo herself says she wasn't
involved with Postgres' hash code.) Credit where credit is due 'n all
that, even if fifteen years after the fact.
< * Allow the creation of indexes with mixed ascending/descending
> * -Allow the creation of indexes with mixed ascending/descending
<
< This is possible now by creating an operator class with reversed sort
< operators. One complexity is that NULLs would then appear at the start
< of the result set, and this might affect certain sort types, like
< merge join.
<
per-column options for btree indexes. The planner's support for this is still
pretty rudimentary; it does not yet know how to plan mergejoins with
nondefault ordering options. The documentation is pretty rudimentary, too.
I'll work on improving that stuff later.
Note incompatible change from prior behavior: ORDER BY ... USING will now be
rejected if the operator is not a less-than or greater-than member of some
btree opclass. This prevents less-than-sane behavior if an operator that
doesn't actually define a proper sort ordering is selected.
when collapsing of JOIN trees is stopped by join_collapse_limit. For instance
a list of 11 LEFT JOINs with limit 8 now produces something like
((1 2 3 4 5 6 7 8) 9 10 11 12)
instead of
(((1 2 3 4 5 6 7 8) (9)) 10 11 12)
The latter structure is really only required for a FULL JOIN.
Noted while studying an example from Shane Ambler.
hash joins with the estimated-larger relation on the inside. There are
several cases where doing that makes perfect sense, and in cases where it
doesn't, the regular cost computation really ought to be able to figure that
out. Make some marginal tweaks in said computation to try to get results
approximating reality a bit better. Per an example from Shane Ambler.
Also, fix an oversight in the original patch to add seq_page_cost: the costs
of spilling a hash join to disk should be scaled by seq_page_cost.
< * Improve the MONEY data type
> * -Make 64-bit version of the MONEY data type
> * Add locale-aware MONEY type, and support multiple currencies
< Change the MONEY data type to use DECIMAL internally, with special
< locale-aware output formatting.
< http://archives.postgresql.org/pgsql-hackers/2006-09/msg01107.php
>
> * Make consistent use of long/short command options --- pg_ctl needs
> long ones, pg_config doesn't have short ones, postgres doesn't have
> enough long ones, etc.
> o Consider parsing the -c string into individual queries so each
> is run in its own transaction
>
> o Consider disallowing multiple queries in PQexec() as an
> additional barrier to SQL injection attacks
< * Allow inherited tables to inherit index, UNIQUE constraint, and primary
< key, foreign key
< * UNIQUE INDEX on base column not honored on INSERTs/UPDATEs from
< inherited table: INSERT INTO inherit_table (unique_index_col) VALUES
< (dup) should fail
<
< The main difficulty with this item is the problem of creating an index
< that can span more than one table.
<
< * Allow SELECT ... FOR UPDATE on inherited tables
> * Inheritance
>
> o Allow inherited tables to inherit indexes, UNIQUE constraints,
> and primary/foreign keys
> o Honor UNIQUE INDEX on base column in INSERTs/UPDATEs
> on inherited table, e.g. INSERT INTO inherit_table
> (unique_index_col) VALUES (dup) should fail
>
> The main difficulty with this item is the problem of
> creating an index that can span multiple tables.
>
> o Allow SELECT ... FOR UPDATE on inherited tables
>
>
>
sets the items, and serializes the value back (rather than adding an
arbitrary number of XML preambles as before).
The libxml memory management via palloc had to be disabled because it
crashes when libxml tries to access memory that was helpfully freed
earlier by PostgreSQL. This needs further thought.
