Oracle and GEM 5.1
Andy Symonds
First there was a technologically superior database
Then there was the best optimizer I've seen
Then there was OSF versions
Then....they came.
What's happening, any ideas how its going to pan out? Did anyone
agree with the statement in Dec Computing (UK) that "Rdbstar was the
only interesting technical aspect of Rdb".
ps. I too have upgraded to Gembase 5.1 and had no problems except the
kit I had expected Decwindows no matter what you replied to the
questions!
andy
---
* 1st 1.11 * 1st does more by 9:00am than other readers do all day
smi...@nova.enet.dec.com
In article <17.21...@almac.co.uk>, andy.s...@almac.co.uk (Andy Symonds) writes:
|>Did anyone
|>agree with the statement in Dec Computing (UK) that "Rdbstar was the
|>only interesting technical aspect of Rdb".
No none of us here in DEC Rdb aggreed. The truth is that much of the RdbStar
advanced development effort is shipping today is the DEC DB Integrator, and
it's associated generation two Gateway products. The author didn't know what
he was talking about.
As far as interesting features of Rdb... compare this list with your favourite
database vendor. This is my own private list, and is not official. I believe
it to be 100% accurate based on my knowledge of the DEC Rdb product (10.5 years
worth which includes application development, consulting and engineering...).
I also do not claim it to be complete in any way... :-) there is so much to
describe.
cheers,
Ian
(Standard disclaimer: These opinions are mine and in no way represent a
commitment or opinion of my employer)
-----------------
- Outstanding Performance history.
Top TPC-A price/performance numbers (3276
System TPS A $/TPS A
Digital 2100-A500MP 4 CPU Client/Server 662.32 $4,401
Digital 2100-A500MP 1 CPU Client/Server 265.03 $4,405
Digital DEC 4000-720 AXP 2 CPU C/S 402.76 $4,861
Digital DEC 7650 AXP 4 nodes 3692.67 $4,866
Includes industry leading SORT algorithm
RMU/BACKUP > 50 GB per hour. RMU/RESTORE 75% of BACKUP
- Row versioning.
When you add, drop or change table definitions there is no need to unload or
reload the data, nor is every row accessed during the alter command. Instead
each version of the table definition is recorded and used at retrieval time to
convert from older versions to the next. This makes metadata changes in a VLDB
environment realistic, many of which can be performed online (i.e. active
production transactions in progress).
- Blob support.
BLOB's have been supported since 1984 (V1.0). Many blob columns can be defined
per row and each column value can access in excess of a terabyte of data
(virtually unlimited in size).
Many vendors are limited to one blob column per table, or restrict a columns
capacity to 2 gigabytes.
The DEC Rdb blob support allows random access to portions of the blob
using scroll cursors (first, last, next, prior, absolute and relative).
Making access to subsets of huge multimedia objects feasible.
- VARCHAR can be over 65000 bytes long. Since 1984 (V1.0).
Many vendors are limited to 2000 bytes.
- Cluster support (VAX, Alpha AXP and mixed)
Full VMS Cluster support (since 1986 V2.2). The same on-disk structure
(optimized for VAX and AXP hardware) is used on all VMS systems. Therefore,
access from VAX or Alpha AXP hardware in a mixed cluster is transparent to the
application.
Have now shipped three releases on both VAX and AXP VMS operating systems.
With the next nearing field testing.
- Unix support now in field test.
A 64 bit implementation of DEC Rdb is running today on OSF/1 for AXP, with
shipment planned for later this year (1994).
- RMU/CONVERT - no unload/reload required for version upgrades. Even allow
RMU/CONVERT/ROLLBACK to previous version.
- Multiversion support. All versions since V4.0 (six versions so far) can be
installed on the same system. Allows easy upgrade by adding new software and
then allowing one application/database to be converted as time permits.
All versions since V4.1 (1991) have supported multiversioning.
- Flexible horizontal partitioning (random or key based) for tables and
indices.
Many of our competitors do not allow table partitioning, which limits their
VLDB support severely.
Vertical and horizontal partition of BLOB data so that a single column can
reference large amounts of data (such as video) stored in the database.
- Several types of HASHED and SORTED indices.
HASH indices allow single I/O access to data which is very important for OLTP
applications which need short response times. Two types of hashing algorithms
are allowed to support a variety of application requirements.
- Row and index compression is user selectable.
- Builtin support for WORM devices. Special algorithms have been implemented
to allow BLOB data to be written to WRITE ONCE READ MANY devices. These
algorithms provide efficient worm platter loading, space utilization and
retrieval. In addition we guarantee the on disk structure will be supported in
the future so that stored data investments on archived worm platters will be
protected.
- Remote access to older and new versions is guaranteed. Allows incremental
upgrade of databases in a large network.
- DEC Rdb has had a cost based optimizer since it's first release (V1.0
1984). It has continually been tuned since then with many innovative
techniques to solve real customer problems.
Some database systems are just now implementing cost based optimizers, which
can't compare in maturity with an optimizer designed and tuned based on real
customer usage for over 10 years.
Only RDBMS with a dynamic optimizer which adapts the access strategy
depending on the data use for the query.
Flexible query outline feature for query fine tuning. The outlines are not
associated with the application but are stored in the database therefore
allowing tuning of queries from any source (SQL or 4GL's). The feature is DBA
controllable to allow specialized tuning. Different user defined modes can be
selected to change the query execution strategy per user, or for different
times of the day.
- Full referential integrity support since it's first release (V1.0 1984).
Other vendors only supported the syntax until recently, or only support some of
the referential integrity features described by SQL standard.
- Allows subqueries to appear anywhere in a query.
I was surprised to learn that many of our competitors restrict where a subquery
can be used, such as only in the select list, or only on the right hand size of
a boolean expression, etc. No such restrictions have ever existed for DEC Rdb
to my knowledge.
- Full Triggers implementation. Since 1989 (V3.1).
- Stored procedures which support both invokers and also definers right
privileges. The language is based on the draft SQL3 standard. It includes
IF-THEN-ELSEIF-ELSE-ENDIF, FOR cursor loop, LOOP, LEAVE, WHILE, CASE, BEGIN/END
with atomicity control, SET TRANSACTION, COMMIT, ROLLBACK, GET DIAGNOSTICS and
SET assignment statement.
- External function callouts.
User define functions written in 3GL's can be called from a SQL query. It's
easy to define and the resulting function looks like an extension to the SQL
language. Feature is based on SQL3 Draft Language Standard.
- ANSI and ISO SQL-92 Entry Level Compliant SQL language. Complete 100% of
all NIST tests for all languages (no other vendor has done this).
Many SQL-92 Intermediate and Full features already exist in the products.
Character set support, left, right and full outer join, date/time arithmetic,
domain constraints, case expression, nullif and coalesce functions.
Many SQL3 features have already been implemented such as stored
procedures, triggers, external function callouts.
- Many enhancements to the SQL language such as COMPUTED BY virtual columns,
partitioned indices, fast direct access to rows via DBKEY, etc.
- Advanced VLDB Support features.
This includes the ability to have multiple after image journal files per
database. Recovery can occur as an entire database, as a single storage area
(operating system file), or at the page level. The result is less down time to
repair hardware (disk) problems.
DEC Rdb allows adding/dropping storage areas online, creation of indices
online and in parallel. Obsolete indices can be taken offline quickly and
Easily using the ALTER INDEX MAINTENANCE IS DISABLED feature.
DEC Rdb was the first relational database system to be 100% MIA
(Multivendor Integration Architecture) compliant. This support includes many
extensions to SQL-92 in the areas of CHARACTER SET definition and management.
DEC Rdb supports a wide range of character sets for Asia (Kanji, Korean,
Chinese, Tiawanese, Thai, India), and Europe (Cyrillic, and Greek). Support has
been available since V4.2. In addition user defined collating sequences have
been available since V3.1 (1989) which support all European languages.
- DEC Rdb support the three read/write isolation levels as described in
SQL-92: SERIALIZABLE, REPEATABLE READ and READ COMMITTED.
Most of our competitors do not support all three levels, making it impossible
for them to run such benchmarks as TPC-C.