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I like algorithms, physics, math, bit manipulation, and
combinatorics. I like experimentation, research, making things
faster, and seeing my work widely used. I want to write my code
myself. C, Java, C++ are fine languages. I don't care which
language as long as it doesn't get in my way. I like to work on
fundamentals. I want to switch out of the Bay Area and out of
databases; otherwise I'll just stay at Oracle.
- Work Experience
-
Oracle (1989-present) I joined Oracle in October 1989 and have
worked there since, except for nine months sabbatical while I pursued
a doctorate at Berkeley (August 1992 - June 1993). Oracle's code (C
and PL/SQL) is very good. It usually doesn't shrink when I edit it.
- Arithmetic (1989-1990) (select 1+2 from dual) I
made Oracle addition faster, multiplication 4x faster, division 6x
faster, square root 66x faster, and added sin, cos, tan, sinh, cosh.
Nobody after me made much headway until Edmund Waugh, about 1998,
doubled the speed of most routines again. (He replaced my
if-statements with table lookups.)
- Snapshots (1990-1995) (create snapshot s as select *
from t@link): I did the first implementation of snapshots
(now called materialized views), updatable snapshots, and the job
queue. Replication took over snapshots and the job queue in 1995 when
I returned to constraints full-time.
- Constraints (1990-present) (create table t (t1 primary
key, t2 references t)) I inherited constraints after the basics
had been finished. I implemented delete cascade, deferred
constraints, unique constraints enforced by nonunique indexes,
constraint/trigger interactions (mutating errors), and
enable-novalidate constraints (which allow constraints to be enabled
without any long term locks).
- Character semantics (2000-present) (varchar2(10
char)) I was in charge of writing the spec for Unicode support
for Oracle 9i (the meetings were many and vigorous) and implementing
it in the RDBMS (three others helped me straighten out the system
quirks that blocked it). I also field most issues with the CHAR
datatype, which uses blankpadded semantics. For example, what do you
pad to when there is both a byte limit and character limit?
- Function-based indexes (1997-2004) (create index ti on
t (t1+1)) I did the functional index design and interface. Three
of us implemented it, combining it with parallel projects for virtual
columns and drop column. I also did descending indexes, including
descend and undescend functions
(sys_op_undescend(sys_op_descend(x)) = x), since the index
layer could only support binary comparison.
- Parser (1998-present) (select p from from q) I own
Oracle's 25 year old 100,000 line recursive-descent SQL parser. This
means I review, but do not write, one to three changes to it a day.
I've been slowly straightening out the parser's quirks. For example,
I recently added tokenizer support for UCS2, and I'm working on
removing the requirements that SQL strings be mutable and
null-terminated.
- General cursor compilation (1989-present) (select *
from (select * from dual)) I've dealt with most of cursor
compilation, as well as row sources and the index layer. I'm a
catch-all for problems that don't fit cleanly in any area, or belong
to code that nobody knowns anymore. For example I recently exposed a
fixed table of all built-in SQL operators and fixed two dozen crashes
that happened when you fed them simple (but inappropriate) arguments.
I've taught the RDBMS architecture course twice.
- Hashing (1997-present): I'm Oracle's resident expert on
hash functions. Hashing is not a one-size-fits-all problem, so I'm
regularly consulted on what hash to use where, how many collisions are
expected with so many buckets, and how many bytes of hash are needed
to make collisions "never" happen. Right now I'm regressing changes
that will make SQL compilation 13% faster, mostly by improving the
use of hashing. I also seek out issues with random numbers,
algorithms, combinatorics, and math.
IBM (1988) I spent an undergraduate summer as an intern at IBM
(Owego, New York) working for Dick Steflik. I debugged a large
educational management system written in REXX. The existing code
tended to shrink when I edited it. I wrote a total of minus 5000
lines of code that summer. I also developed a new tool to
automatically lay out text heirarchy charts that looked like ones
built by hand.
- Education
-
Undergraduate (plus masters) (1985-1989) Carnegie Mellon University.
I graduated with a BS in Computer Science and a masters in math, QPA
3.7. My master's thesis was a new dynamic
algorithm for calculating the HOMFLY polynomial for directed knots
and links. I drew cartoons for
both campus papers.
Graduate (1992-1993) I spent a year at Berkeley in the
doctoral program for theoretical computer science, but returned to
industry after deciding I didn't want to be a professor.
- Other Projects
-
I develop software tools and primitives at home. I put it all on
my web site, public
domain.
I'm interested in cryptographic primitives. My pseudorandom
number generator, ISAAC, was
presented at the 1996 Fast Software Encryption Conference. It hasn't
been broken, it hasn't seen much analysis, it hasn't been widely used.
I developed some test
suites to test
ISAAC, and have also used them to find biases in RC4 and many other CPRNGs
proposed on sci.crypt. I can break 5-bit RC4. I
have another generator, FLEA, in the works.
Hashes for hash table lookup are similar to cryptographic
block ciphers. I developed some theory for what
makes a good hash function for hash table lookup. I wrote a hash sieve
to generate random hashes and see if they are good. It could screen
ten a second. And I proposed two good hashes, one in a September 1997
Dr. Dobb's article. They have been used at one time or another by
Oracle, Infoseek, Dreamworks (Shrek), Perl, Ruby, Linux, and Google.
I've also implemented a perfect hash
generator which can find a perfect hash for a million keys (no
collisions) in a minute.
The surprising efficiency of my hash sieve led me to develop jenny, a
pairwise testing tool. Pairwise testing produces
cross-functional regression tests that are radically shorter and more
thorough than tests produced by most other strategies. I'm currently
developing another tool, bnfpair, that will do pairwise testing for
systems described in BNF.
I wrote an orbital applet in Java to simulate a set of
orbits I'd designed that should form a Dyson Sphere.
I have online simulations of the solar
system,
Cruithne,
and Klemperer
Rosettes. I had to derive a 9th degree
symmetric multistep method because the
existing methods I could find (leapfrog, Runge Kutta, Runge Kutta
Fehlberg) weren't accurate enough for my purposes. I later found my
multistep method was reinventing the wheel (a rather common thing for
me to find).
I've done many other things. I've found pentagons
that tile the plane, found perpetual
motion machines (and handwaved at why they don't work), designed a house, built a
dollhouse,
collected scout
skits, written songs for the harmonica, painted a mural,
argued for approval voting,
designed a distributed HTML
index, learned to solve Rubik's cube, automated finding
iterated
characteristics of block ciphers, and compiled tables of lexicodes
(d=3..33). Some things succeed, some things don't, some turn out to
be duplicates of other people's work, some work and are new but
nobody's interested.
I don't watch TV, or play sports, or participate in any organized
activities. I do follow science, read science fiction, and play my
harmonica. Most of my time outside of work these days goes to raising
kids.
References are available upon request. Contact me via email at
bob_jenkins@burtleburtle.net.
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