Software Gems' Sybase Gem Documents
This list contains documents that have been made up for public consumption. Initially the Memory Tag
pages from our Sybase education materials, or derived from our presentations.
They bring all the information about a subject together, in one place. They clarify confusing subjects or those that are
treated poorly in the manuals. They are intended to improve your understanding of Sybase ASE,
and thus increase the Quality and Performance of your Sybase server, and your effectiveness as a DBA.
Note that they are quite condensed and we are told, have that Gem quality about them.
If you are new to the material, take your time and consume it in small quantities.
While Memory Tag pages look great, cover the named subject fully, and work well for experienced people,
they are not as effective for people who have not had the benefit of the course: there is nothing in the memory to tag.
Therefore I get a lot of questions, and I keep upgrading the content (please check for updates).
It has now left Memory Tag territory, and it is approaching textbook level. Two formats are provided.
There is an awful lot of shallow, inaccurate, misleading and false information on the Internet. Unfortunately some of that false or
misleading information is published by Sybase, both in the manuals, and on the web. These documents provide
full and complete information (albeit very condensed) about each subject, such that the reader is no longer vulnerable to false or confusing
These documents were originally formatted and produced as stand-alone PDFs for download.
This will not change because the portability, quality and nagivation are unmatched; the complex illustrations show
up best in PDF; and they are heavily cross-referenced via links. Blue glass buttons provide navigation across the major headings.
Use the full power of your PDF viewer capabilities, including Search, etc, if you can open them.
Unfortunately the combination of certain browsers::PDF viewers cannot open the PDFs
(so much for the ability of commercial programs to read Standard-compliant files).
- HTML Image Map
Based on your feedback most of the documents have been re-published as HTML,
from the same source, for viewing in sub-standard browsers.
This is rendered as one PNG image per A4 page, with image quality understandably poorer than PDF.
Use your browser capabilities: either use the Next links and follow the material in the sequence it is presented;
or select the objects and jump around to follow your interest. Blue glass buttons provide navigation across the major headings.
- Document Map
Years ago, a few single pages derived from our education materials were posted, as reference to my discussions on fora.
Over time, on the basis of feedback and continued interaction, this has grown into several documents, now integrated and cross-linked.
The sections in each document keep growing as well.
What was once a number of single pages which were issue-oriented, has evolved into structured,
reference-oriented, multi-page documents.
A Document Map is now called for; this allows you to review the structure and subject sections and to go directly to them.
- Data Storage V2.5
Detailed and illustrated.
Defines Units of storage and their relations; the five DataStructures and Partitions; all Index Structures and their relations;
and introduces Devices and Segments in context. Those hunting the snark or the invisible DOL "clustered" index will find it here.
For those seeking a deeper understanding or intending to write utilities may appreciate
the Sybase Catalogue pertaining to DataStructures; and the exposition of all DataStructures and their relations
in terms of a full Data Model.
- Fragmentation V2.5
Detailed and illustrated. Version 2.5 is substantially expanded, based on your feedback (thank you!).
- Defines all the Types of Fragmentation, within three distinct Levels, as it applies to each Data Storage Unit,
and the impact at each Level/Unit
- New chapter on Determination of each Type of Fragmentation, detailing not only the methods,
but the considerations for each metric
- Each type of Fragmentation illustrated and discussed
- For DOL-only Fragmentation, the effect of each command is illustrated and discussed
- Explains why common de-fragmentation operations do not work
- Provides a solid foundation for prevention of Level I Fragmentation, and returning great speed to the Data Structures
- Provides methods of correcting Fragmentation, and for reducing the frequency of de-fragmentation operations
- Where the difference between APL and DPL/DRL lockschemes is relevant, these are compared side-by-side.
- Index Type V2.5
An older document, it describes and compares APL vs DPL/DRL Index Types in summary form, on a single page.
- Data Storage & Fragmentation V2.5
The above three documents, provided in a single PDF, with all links and references resolved. 31 condensed pages.
- Cache Behaviour V2.3.1
A full explanation of all aspects of the behaviour of ASE caches and pools, using illustrations: how they operate;
considerations re the Wash Area;
the two cache strategies; overload scenarios; large I/O pools, in terms of both reading and writing;
partitioning the cache; and Asynch Pre-Fetch.
The information is essential for understanding ASE caches, and for configuring and tuning them correctly.
The only element not detailed is site-specific cache sizing and configuration guidelines
(our High Performance Configuration,
which includes a full set of site-specific caches, is available for purchase).
- Statistics Demystified V2.1 (Draft)
Simplifies and fully explains Statistics. Presented with many illustrations, in three parts, with two examples of meaningful Statistics
reports from our utilities:
- Concepts: that need to be understood, in order to identify which Stats are relevant, and to maintain them properly
- Catalogue: useful for a deeper understanding of issues, and for writing your own Statistics reports
- UPDATE STATS: the effect of each of the different flavours of the command.
- Help Statistic: displays Statistics and their relations to all relevant items (Indices; other Stats; columns) on one page,
at both the Table and Partition levels.
- Help Histogram: displays the Histograms in a human-readable format,
and has advantages over optdiag.
A consolidated report (Statistics plus Histograms in 3 columns) intended for landscape printing is also provided,
again at both Table and Partition levels.
- Lock Manager V2.6
An illustrated overview of the operation of the Lock Manager, in three pages.
It shows all commonly encountered types of locks within ASE; how they are used; how they are escalated and promoted.
It tabulates ISOLATION LEVELS vis-a-vis locks,
and clarifies the transaction/session/query/table context.
Configuration considerations and the different types of contention resolution metods (locks, latches, LW Protection,
and Spinlocks) are discussed.
- MDA Collector V1.4
MDA Source PDF
In our Technical Audits, Performance Tuning & Verification, we use Sysmon exclusively, due to its richness and zero overhead;
and provide a full-featured Sysmon Processor.
For those customers who insist on MDA, we support the Monitoring aspect of MDA tables (of which the overheads are bad enough)
as a second preference to Sysmon, but not the Diagnostic aspect (of which the overhead and processing requirements are horrendous).
We provide a full-featured MDA Collector for this purpose.
There are much cheaper and less onerous methods of diagnosis.
These documents posted here because we are told they assist people in understanding MDA, and in writing their own MDA Collector.
The first document is a single page overview of the MDA Collector database, showing the ERD and the command syntax for this utility.
The second document identifies the MDA source for each table; the cofiguration options required; and the MDA overhead for each;
it may be laid over the first document.
- RAID5 vs RAID1+0
A substantiated review, with many links, for those who need to overcome the false information provided by SAN salesmen and lazy StorageTeams,
that one great big RAID5 volume is acceptable for databases. Page 5 provides an illustration.
- SAN Configuration Guide for Sybase ASE
The several levels of configuration of the Logical Volumes in the SAN is very important, as it seriously affects the performance and isolation of your ASE server and your databases.
We provide a complete Guide, that addresses the issues and consequences in detail,
currently over 50 pages, available for purchase.
The document above identifies the first line of issues that require address in response to the pathetically slow RAID5,
which is commonly pressed as the answer to every data storage requirement; it is provided free of charge.
Page Updated 08 Jun 13 ·
Gratitude or feedback