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Archive-name: databases/sybase-faq/part4
URL: http://www.isug.com/Sybase_FAQ Version: 1.7 Maintainer: David Owen Last-modified: 2003/03/02 Posting-Frequency: posted every 3rd month A how-to-find-the-FAQ article is posted on the intervening months. Sybase Frequently Asked Questions See reader questions & answers on this topic! - Help others by sharing your knowledge
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Adaptive Server Enterprise
0. What's in a name?
1. ASE Administration
1.1 Basic Administration
1.2 User Database Administration
1.3 Advanced Administration
1.4 General Troubleshooting
1.5 Performance and Tuning
1.6 Server Monitoring
2. Platform Specific Issues
2.1 Solaris
2.2 NT
2.3 Linux
3. DBCC's
4. isql
5. bcp
6. SQL Development
6.1 SQL Fundamentals
6.2 SQL Advanced
6.3 Useful SQL Tricks
7. Open Client
9. Freeware
10. Sybase Technical News
11. Additional Information
12. Miscellany
-------------------------------------------------------------------------------
What's in a name?
Throughout this FAQ you will find references to SQL Server and, starting with
this release, ASE or Adaptive Server Enterprise to give it its full name. You
might also be a little further confused, since Microsoft also seem to have a
product called SQL Server.
Well, back at about release 4.2 of Sybase SQL Server, the products were exactly
the same. Microsoft were to do the port to NT. Well, it is pretty well
documented, but there was a falling out. Both companies kept the same name for
their data servers and confusion began to reign. In an attempt to try and sort
this out, Sybase renamed their product Adaptive Server Enterprise (ASE)
starting with version 11.5.
I found this quote in a Sybase manual the other day:
Since changing the name of Sybase SQL Server to Adaptive Server Enterprise,
Sybase uses the names Adaptive Server and Adaptive Server Enterprise to refer
collectively to all supported versions of the Sybase SQL Server and Adaptive
Server Enterprise. Version-specific references to Adaptive Server or SQL Server
include version numbers.
I will endeavour to try and do the same within the FAQ, but the job is far from
complete!
Back to Top
Basic ASE Administration
1.1.1 What is SQL Server and ASE anyway?
1.1.2 How do I start/stop ASE when the CPU reboots?
1.1.3 How do I move tempdb off of the master device?
1.1.4 How do I correct timeslice -201?
1.1.5 The how's and why's on becoming Certified.
1.1.6 RAID and Sybase
1.1.7 How to swap a db device with another
1.1.8 Server naming and renaming
1.1.9 How do I interpret the tli strings in the interface file?
1.1.10 How can I tell the datetime my Server started?
1.1.11 Raw partitions or regular files?
1.1.12 Is Sybase Y2K (Y2000) compliant?
1.1.13 How can I run the ASE upgrade manually?
1.1.14 We have lost the sa password, what can we do?
1.1.15 How do I set a password to be null?
1.1.16 Does Sybase support Row Level Locking?
1.1.17 What platforms does ASE run on?
1.1.18 How do I backup databases > 64G on ASE prior to 12.x?
User Database Administration # ASE FAQ
-------------------------------------------------------------------------------
1.1.1: What is SQL Server and ASE?
-------------------------------------------------------------------------------
Overview
Before Sybase System 10 (as they call it) we had Sybase 4.x. Sybase System 10
has some significant improvements over Sybase 4.x product line. Namely:
* the ability to allocate more memory to the dataserver without degrading its
performance.
* the ability to have more than one database engine to take advantage of
multi-processor cpu machines.
* a minimally intrusive process to perform database and transaction dumps.
Background and More Terminology
A ASE (SQL Server) is simply a Unix process. It is also known as the database
engine. It has multiple threads to handle asynchronous I/O and other tasks. The
number of threads spawned is the number of engines (more on this in a second)
times five. This is the current implementation of Sybase System 10, 10.0.1 and
10.0.2 on IRIX 5.3.
Each ASE allocates the following resources from a host machine:
* memory and
* raw partition space.
Each ASE can have up to 255 databases. In most implementations the number of
databases is limited to what seems reasonable based on the load on the ASE.
That is, it would be impractical to house all of a large company's databases
under one ASE because the ASE (a Unix process) will become overloaded.
That's where the DBAs experience comes in with interrogation of the user
community to determine how much activity is going to result on a given database
or databases and from that we determine whether to create a new ASE or to house
the new database under an existing ASE. We do make mistakes (and businesses
grow) and have to move databases from one ASE to another. At times ASEs need to
move from one CPU server to another.
With Sybase System 10, each ASE can be configured to have more than one engine
(each engine is again a Unix process). There's one primary engine that is the
master engine and the rest of the engines are subordinates. They are assigned
tasks by the master.
Interprocess communication among all these engines is accomplished with shared
memory.
Some times when a DBA issues a Unix kill command to extinguish a maverick
ASE, the subordinate engines are forgotten. This leaves the shared memory
allocated and eventually we may get in to situations where swapping occurs
because this memory is locked. To find engines that belong to no master
ASE, simple look for engines owned by /etc/init (process id 1). These
engines can be killed -- this is just FYI and is a DBA duty.
Before presenting an example of a ASE, some other topics should be covered.
Connections
An ASE has connections to it. A connection can be viewed as a user login but
it's not necessarily so. That is, a client (a user) can spark up multiple
instances of their application and each client establishes its own connection
to the ASE. Some clients may require two or more per invocation. So typically
DBA's are only concerned with the number of connections because the number of
users typically does not provide sufficient information for us to do our job.
Connections take up ASE resources, namely memory, leaving less memory for
the ASEs' available cache.
ASE Buffer Cache
In Sybase 4.0.1 there was a limit to the amount of memory that could be
allocated to a ASE. It was around 80MB, with 40MB being the typical max. This
was due to internal implementations of Sybase's data structures.
With Sybase System 10 there really was no limit. For instance, we had an ASE
cranked up to 300MB under 10. With System 11 and 12 this has been further
extended. ASE's with 4G bytes of memory are not uncommon. I have not heard of
an 11.9.3 or a 12 server with more that 4G bytes, but I am sure that they are
not far away.
The memory in an ASE is primarily used to cache data pages from disk. Consider
that the ASE is a light weight Operating System: handling user (connections),
allocating memory to users, keeping track of which data pages need to be
flushed to disk and the sort. Very sophisticated and complex. Obviously if a
data page is found in memory it's much faster to retrieve than going out to
disk.
Each connection takes away a little bit from the available memory that is used
to cache disk pages. Upon startup, the ASE pre-allocates the memory that is
needed for each connection so it's not prudent to configure 500 connections
when only 300 are needed. We'd waste 200 connections and the memory associated
with that. On the other hand, it is also imprudent to under configure the
number of connections; users have a way of soaking up a resource (like an ASE)
and if users have all the connections a DBA cannot get into the server to
allocate more connections.
One of the neat things about an ASE is that it reaches (just like a Unix
process) a working set. That is, upon startup it'll do a lot of physical I/O's
to seed its cache, to get lookup information for typical transactions and the
like. So initially, the first users have heavy hits because their requests have
to be performed as a physical I/O. Subsequent transactions have less physical I
/O and more logical I/O's. Logical I/O is an I/O that is satisfied in the ASEs'
buffer cache. Obviously, this is the preferred condition.
DSS vs OLTP
We throw around terms like everyone is supposed to know this high tech lingo.
The problem is that they are two different animals that require a ASE to be
tuned accordingly for each.
Well, here's the low down.
DSS
Decision Support System
OLTP
Online Transaction Processing
What do these mean? OLTP applications are those that have very short orders of
work for each connection: fetch this row and with the results of it update one
or two other rows. Basically, small number of rows affected per transaction in
rapid sucession, with no significant wait times between operations in a
transaction.
DSS is the lumbering elephant in the database world (unless you do some
tricks... out of this scope). DSS requires a user to comb through gobs of data
to aggregate some values. So the transactions typically involve thousands of
rows. Big difference than OLTP.
We never want to have DSS and OLTP on the same ASE because the nature of OLTP
is to grab things quickly but the nature of DSS is to stick around for a long
time reading tons of information and summarizing the results.
What a DSS application does is flush out the ASE's data page cache because of
the tremendous amount of I/O's. This is obviously very bad for OTLP
applications because the small transactions are now hurt by this trauma. When
it was only OLTP a great percentage of I/O was logical (satisfied in the
cache); now transactions must perform physical I/O.
That's why it's good not to mix DSS and OLTP if at all possible.
If mixing them cannot be avoided, then you need to think carefully about how
you configure your server. Use named data caches to ensure that the very
different natures of OLTP and DSS do not conflict with each other. If you
tables that are shared, consider using dirty reads for the DSS applications if
at all possible, since this will help not to block the OLTP side.
Asynchronous I/O
Why async I/O? The idea is that in a typical online transaction processing
(OLTP) application, you have many connections (over 200 connections) and short
transactions: get this row, update that row. These transactions are typically
spread across different tables of the databases. The ASE can then perform each
one of these asynchronously without having to wait for others to finish. Hence
the importance of having async I/O fixed on our platform.
Engines
Sybase System 10 can have more than one engine (as stated above). Sybase has
trace flags to pin the engines to a given CPU processor but we typically don't
do this. It appears that the master engine goes to processor 0 and subsequent
subordinates to the next processor.
Currently, Sybase does not scale linearly. That is, five engines do not make
Sybase perform five times as fast however we do max out with four engines.
After that performance starts to degrade. This is supposed to be fixed with
Sybase System 11.
Putting Everything Together
As previously mentioned, an ASE is a collection of databases with connections
(that are the users) to apply and retrieve information to and from these
containers of information (databases).
The ASE is built and its master device is typically built over a medium sized
(50MB) raw partition. The tempdb is built over a cooked (regular - as opposed
to a raw device) file system to realize any performance gains by buffered
writes. The databases themselves are built over the raw logical devices to
ensure their integrity. (Note: in System 12 you can use the dsync flag to
ensure that writes to file system devices are secure.
Physical and Logical Devices
Sybase likes to live in its own little world. This shields the DBA from the
outside world known as Unix, VMS or NT. However, it needs to have a conduit to
the outside world and this is accomplished via devices.
All physical devices are mapped to logical devices. That is, given a physical
device (such as /lv1/dumps/tempdb_01.efs or /dev/rdsk/dks1ds0) it is mapped by
the DBA to a logical device. Depending on the type of the device, it is
allocated, by the DBA, to the appropriate place (vague enough?).
Okay, let's try and clear this up...
Dump Device
The DBA may decide to create a device for dumping the database nightly. The DBA
needs to create a dump device.
We'll call that logically in the database datadump_for_my_db but we'll map it
to the physical world as /lv1/dumps/in_your_eye.dat So the DBA will write a
script that connects to the ASE and issues a command like this:
dump database my_stinking_db to datadump_for_my_db
go
and the backupserver (out of this scope) takes the contents of my_stinking_db
and writes it out to the disk file /lv1/dumps/in_your_eye.dat
That's a dump device. The thing is that it's not preallocated. This special
device is simply a window to the operating system.
Data and Log Devices
Ah, now we are getting into the world of pre-allocation. Databases are built
over raw partitions. The reason for this is because Sybase needs to be
guaranteed that all its writes complete successfully. Otherwise, if it posted
to a file system buffer (as in a cooked file system) and the machine crashed,
as far as Sybase is concerned the write was committed. It was not, however, and
integrity of the database was lost. That is why Sybase needs raw partitions.
But back to the matter at hand...
When building a new ASE, the DBA determines how much space they'll need for all
the databases that will be housed in this ASE.
Each production database is composed of data and log.
The data is where the actual information resides. The log is where the changes
are kept. That is, every row that is updated/deleted/inserted gets placed into
the log portion then applied to the data portion of the database.
That's why DBA strives to place the raw devices for logs on separate disks
because everything has to single thread through the log.
A transaction is a collection of SQL statements (insert/delete/update) that are
grouped together to form a single unit of work. Typically they map very closely
to the business.
I'll quote the Sybase ASE Administration Guide on the role of the log:
The transaction log is a write-ahead log. When a user issues a statement
that would modify the database, ASE automatically writes the changes to the
log. After all changes for a statement have been recorded in the log, they
are written to an in-cache copy of the data page. The data page remains in
cache until the memory is needed for another database page. At that time,
it is written to disk. If any statement in a transaction fails to complete,
ASE reverses all changes made by the transaction. ASE writes an "end
transaction" record to the log at the end of each transaction, recording
the status (success or failure) of the transaction
As such, the log will grow as user connections affect changes to the database.
The need arises to then clear out the log of all transactions that have been
flushed to disk. This is performed by issuing the following command:
dump transaction my_stinking_db to logdump_for_my_db
go
The ASE will write to the dumpdevice all transactions that have been committed
to disk and will delete the entries from its copy, thus freeing up space in the
log. Dumping of the transaction logs is accomplished via cron (the Unix
scheduler, NT users would have to resort to at or some third party tool) . We
schedule the heavily hit databases every 20 minutes during peak times.
A single user can fill up the log by having begin transaction with no
corresponding commit/rollback transaction. This is because all their
changes are being applied to the log as an open-ended transaction, which is
never closed. This open-ended transaction cannot be flushed from the log,
and therefore grows until it occupies all of the free space on the log
device.
And the way we dump it is with a dump device. :-)
An Example
If the DBA has four databases to plop on this ASE and they need a total of
800MB of data and 100MB of log (because that's what really matters to us), then
they'd probably do something like this:
1. allocate sufficient raw devices to cover the data portion of all the
databases
2. allocate sufficient raw devices to cover the log portion of all the
databases
3. start allocating the databases to the devices.
For example, assuming the following database requirements:
Database
Requirements
+-----------------+
| | | |
|----+------+-----|
| DB | Data | Log |
|----+------+-----|
|----+------+-----|
| a | 300 | 30 |
|----+------+-----|
| b | 400 | 40 |
|----+------+-----|
| c | 100 | 10 |
+-----------------+
and the following devices:
Devices
+---------------------------------+
| Logical | Physical | Size |
|---------------+----------+------|
| | /dev/ | |
| dks3d1s2_data | rdsk/ | 500 |
| | dks3d1s2 | |
|---------------+----------+------|
| | /dev/ | |
| dks4d1s2_data | rdsk/ | 500 |
| | dks4d1s2 | |
|---------------+----------+------|
| | /dev/ | |
| dks5d1s0_log | rdsk/ | 200 |
| | dks5d1s0 | |
+---------------------------------+
then the DBA may elect to create the databases as follows:
create database a on dks3d1s2_data = 300 log on dks5d1s0_log = 30
create database b on dks4d1s2_data = 400 log on dks5d1s0_log = 40
create database c on dks3d1s2_data = 50, dks4d1s2_data = 50 log on dks5d1s0_log = 10
Some of the devices will have extra space available because out database
allocations didn't use up all the space. That's fine because it can be used for
future growth. While the Sybase ASE is running, no other Sybase ASE can
re-allocate these physical devices.
TempDB
TempDB is simply a scratch pad database. It gets recreated when a SQL Server is
rebooted. The information held in this database is temporary data. A query may
build a temporary table to assist it; the Sybase optimizer may decide to create
a temporary table to assist itself.
Since this is an area of constant activity we create this database over a
cooked file system which has historically proven to have better performance
than raw - due to the buffered writes provided by the Operating System.
Port Numbers
When creating a new ASE, we allocate a port to it (currently, DBA reserves
ports 1500 through 1899 for its use). We then map a host name to the different
ports: hera, fddi-hera and so forth. We can actually have more than one port
number for an ASE but we typically don't do this.
Back to top
-------------------------------------------------------------------------------
1.1.2: How to start/stop ASE when CPU reboots
-------------------------------------------------------------------------------
Below is an example of the various files (on Irix) that are needed to start/
stop an ASE. The information can easily be extended to any UNIX platform.
The idea is to allow as much flexibility to the two classes of administrators
who manage the machine:
* The System Administrator
* The Database Administrator
Any errors introduced by the DBA will not interfere with the System
Administrator's job.
With that in mind we have the system startup/shutdown file /etc/init.d/sybase
invoking a script defined by the DBA: /usr/sybase/sys.config/
{start,stop}.sybase
/etc/init.d/sybase
On some operating systems this file must be linked to a corresponding entry in
/etc/rc.0 and /etc/rc.2 -- see rc0(1M) and rc2(1M)
#!/bin/sh
# last modified: 10/17/95, sr.
#
# Make symbolic links so this file will be called during system stop/start.
# ln -s /etc/init.d/sybase /etc/rc0.d/K19sybase
# ln -s /etc/init.d/sybase /etc/rc2.d/S99sybase
# chkconfig -f sybase on
# Sybase System-wide configuration files
CONFIG=/usr/sybase/sys.config
if $IS_ON verbose ; then # For a verbose startup and shutdown
ECHO=echo
VERBOSE=-v
else # For a quiet startup and shutdown
ECHO=:
VERBOSE=
fi
case "$1" in
'start')
if $IS_ON sybase; then
if [ -x $CONFIG/start.sybase ]; then
$ECHO "starting Sybase servers"
/bin/su - sybase -c "$CONFIG/start.sybase $VERBOSE &"
else
<error condition>
fi
fi
;;
'stop')
if $IS_ON sybase; then
if [ -x $CONFIG/stop.sybase ]; then
$ECHO "stopping Sybase servers"
/bin/su - sybase -c "$CONFIG/stop.sybase $VERBOSE &"
else
<error condition>
fi
fi
;;
*)
echo "usage: $0 {start|stop}"
;;
esac
/usr/sybase/sys.config/{start,stop}.sybase
start.sybase
#!/bin/sh -a
#
# Script to start sybase
#
# NOTE: different versions of sybase exist under /usr/sybase/{version}
#
# Determine if we need to spew our output
if [ "$1" != "spew" ] ; then
OUTPUT=">/dev/null 2>&1"
else
OUTPUT=""
fi
# 10.0.2 servers
HOME=/usr/sybase/10.0.2
cd $HOME
# Start the backup server
eval install/startserver -f install/RUN_BU_KEPLER_1002_52_01 $OUTPUT
# Start the dataservers
# Wait two seconds between starts to minimize trauma to CPU server
eval install/startserver -f install/RUN_FAC_WWOPR $OUTPUT
sleep 2
eval install/startserver -f install/RUN_MAG_LOAD $OUTPUT
exit 0
stop.sybase
#!/bin/sh
#
# Script to stop sybase
#
# Determine if we need to spew our output
if [ -z "$1" ] ; then
OUTPUT=">/dev/null 2>&1"
else
OUTPUT="-v"
fi
eval killall -15 $OUTPUT dataserver backupserver sybmultbuf
sleep 2
# if they didn't die, kill 'em now...
eval killall -9 $OUTPUT dataserver backupserver sybmultbuf
exit 0
If your platform doesn't support killall, it can easily be simulated as
follows:
#!/bin/sh
#
# Simple killall simulation...
# $1 = signal
# $2 = process_name
#
#
# no error checking but assume first parameter is signal...
# what ya want for free? :-)
#
kill -$1 `ps -ef | fgrep $2 | fgrep -v fgrep | awk '{ print $1 }'`
Back to top
-------------------------------------------------------------------------------
1.1.3: How do I move tempdb off of the Master Device?
-------------------------------------------------------------------------------
There used to be a section in the FAQ describing how to drop all of tempdb's
devices physically from the master device. This can make recovery of the
server impossible in case of a serious error and so it strongly recommended
that you do not do this but simply drop the segments as outlined below.
Sybase TS Preferred Method of Moving tempdb off the Master Device.
This is the Sybase TS method of removing most activity from the master device:
1. Alter tempdb on another device:
1> alter database tempdb on ...
2> go
2. Use the tempdb:
1> use tempdb
2> go
3. Drop the segments:
1> sp_dropsegment "default", tempdb, master
2> go
1> sp_dropsegment "logsegment", tempdb, master
2> go
1> sp_dropsegment "system", tempdb, master
2> go
Note that there is still some activity on the master device. On a three
connection test that I ran:
while ( 1 = 1 )
begin
create table #x (col_a int)
drop table #x
end
there was one write per second. Not bad.
An Alternative
(I recently did some bench marks comparing this method, the previous method
and a combination of both. According to sp_sysmon there was no difference
in activity at all. I leave it here just in case it proves useful to
someone.)
The idea of this handy script is to simply fill the first 2MB of tempdb thus
effectively blocking anyone else from using it. The slight gotcha with this
script, since we're using model, is that all subsequent database creates will
also have tempdb_filler installed. This is easily remedied by dropping the
table after creating a new database.
This script works because tempdb is rebuilt every time the ASE is rebooted.
Very nice trick!
/* this isql script creates a table in the model database. */
/* Since tempdb is created from the model database when the */
/* server is started, this effectively moves the active */
/* portion of tempdb off of the master device. */
use model
go
/* note: 2k row size */
create table tempdb_filler(
a char(255) not null,
b char(255) not null,
c char(255) not null,
d char(255) not null,
e char(255) not null
)
go
/* insert 1024 rows */
declare @i int
select @i = 1
while (@i <= 1024)
begin
insert into tempdb_filler values('a','b','c','d','e')
if (@i % 100 = 0) /* dump the transaction every 100 rows */
dump tran model with truncate_only
select @i=@i+1
end
go
Back to top
-------------------------------------------------------------------------------
1.1.4: How do I correct timeslice -201
-------------------------------------------------------------------------------
(Note, this procedure is only really necessary with pre-11.x systems. In
system 11 systems, these parameters are tunable using sp_configure.)
Why Increase It?
Basically, it will allow a task to be scheduled onto the CPU for a longer time.
Each task on the system is scheduled onto the CPU for a fixed period of time,
called the timeslice, during which it does some work, which is resumed when its
next turn comes around.
The process has up until the value of ctimemax (a config block variable) to
finish its task. As the task is working away, the scheduler counts down
ctimemax units. When it gets to the value of ctimemax - 1, if it gets stuck and
for some reason cannot be taken off the CPU, then a timeslice error gets
generated and the process gets infected.
On the other hand, ASE will allow a server process to run as long as it needs
to. It will not swap the process out for another process to run. The process
will decide when it is "done" with the server CPU. If, however, a process goes
on and on and never relinquishes the server CPU, then Server will timeslice the
process.
Potential Fix
1. Shutdown the ASE
2. %buildmaster -dyour_device -yctimemax=2000
3. Restart your ASE. If the problem persists contact Sybase Technical Support
notifying them what you have done already.
Back to top
-------------------------------------------------------------------------------
1.1.5: Certified Sybase Professional
-------------------------------------------------------------------------------
There have been changes in the process of becoming a Sybase Certified
Professional. There's a very informative link at http://www.sybase.com/
education/profcert, Professional Certification.
Rob Verschoor has put together some good stuff on his pages ( http://
www.euronet.nl/~syp_rob/certtips.html) that have pretty much all that you need
to know. He also has a quiz which is intended to test each and everyone's
knowledge of ASE and RepServer.
Sybase have released some sample questions (look for them at http://
www.sybase.com/education/). The GUI requires MS Windows (at the time of
writing), but they are definitely a sample of what you will be asked. There are
also a couple of CDs available with yet more questions on them.
The Certification Kickback
There have been a couple of articles recently covering the kickback that seems
to be happening as far as certification is concerned. Serveral HR people have
said that if a person's CV (resume) is sent in covered in certifications then
it goes straight into the bit bucket. I do not know if this is true or not, but
one thing that you might wish to consider is the preparation of two CVs, one
with certifications, one without. If the job request specifies certification is
necessary, then send in the appropriate CV. If it does not specifiy
certification, send in the clean version. If you go into the interview for a
job that did not specify certifications up front and the interviewer starts
going about you not being certificated, you simply produce your card as proof.
-------------------------------------------------------------------------------
1.1.6: RAID and Sybase
-------------------------------------------------------------------------------
Here's a short summary of what you need to know about Sybase and RAID.
The newsgroup comp.arch.storage has a detailed FAQ on RAID, but here are a few
definitions:
RAID
RAID means several things at once. It provides increased performance through
disk striping, and/or resistance to hardware failure through either mirroring
(fast) or parity (slower but cheaper).
RAID 0
RAID 0 is just striping. It allows you to read and write quickly, but provides
no protection against failure.
RAID 1
RAID 1 is just mirroring. It protects you against failure, and generally reads
and writes as fast as a normal disk. It uses twice as many disks as normal (and
sends twice as much data across your SCSI bus, but most machines have plenty of
extra capacity on their SCSI busses.)
Sybase mirroring always reads from the primary copy, so it does not
increase read performance.
RAID 0+1
RAID 0+1 (also called RAID 10) is striping and mirroring together. This gives
you the highest read and write performance of any of the raid options, but uses
twice as many disks as normal.
RAID 4/RAID 5
RAID 4 and 5 have disk striping and use 1 extra disk to provide parity. Various
vendors have various optimizations, but this RAID level is generally much
slower at writes than any other kind of RAID.
RAID 7
I am not sure if this is a genuine RAID standard, further checking on your part
is required.
Details
Most hardware RAID controllers also provide a battery-backed RAM cache for
writing. This is very useful, because it allows the disk to claim that the
write succeeded before it has done anything. If there is a power failure, the
information will (hopefully) be written to disk when the power is restored. The
cache is very important because database log writes cause the process doing the
writes to stop until the write is successful. Systems with write caching thus
complete transactions much more quickly than systems without.
What RAID levels should my data, log, etc be on? Well, the log disk is
frequently written, so it should not be on RAID 4 or 5. If your data is
infrequently written, you could use RAID 4 or 5 for it, because you don't mind
that writes are slow. If your data is frequently written, you should use RAID
0+1 for it. Striping your data is a very effective way of avoiding any one disk
becoming a hot-spot. Traditionally Sybase databases were divided among devices
by a human attempting to determine where the hot-spots are. Striping does this
in a straight-forward fashion, and also continues to work if your data access
patterns change.
Your tempdb is data but it is frequently written, so it should not be on RAID 4
or 5.
If your RAID controller does not allow you to create several different kinds of
RAID volumes on it, then your only hope is to create a huge RAID 0+1 set. If
your RAID controller does not support RAID 0+1, you shouldn't be using it for
database work.
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-------------------------------------------------------------------------------
1.1.7: How to swap a db device with another
-------------------------------------------------------------------------------
Here are four approaches. Before attempting any of the following: Backup,
Backup, Backup.
Dump and Restore
1. Backup the databases on the device, drop the databases, drop the devices.
2. Rebuild the new devices.
3. Rebuild the databases (Make sure you recreate the fragments correctly - See
Ed Barlow's scripts (http://www.tiac.net/users/sqltech/) for an sp that
helps you do this if you've lost your notes. Failure to do this will
possibly lead to data on log segments and log on data segments).
4. Reload the database dumps!
Twiddle the Data Dictionary - for brave experts only.
1. Shut down the server.
2. Do a physical dump (using dd(1), or such utility) of the device to be
moved.
3. Load the dump to the new device
4. Edit the data dictionary (sysdevices.physname) to point to the new device.
The Mirror Trick
1. Create a mirror of the old device, on the new device.
2. Unmirror the primary device, thereby making the _backup_ the primary
device.
3. Repeat this for all devices until the old disk is free.
dd (Unix only)
(This option is no use if you need to move a device now, rather if you
anticipate moving a device at some point in the future.)
You may want to use this approach for creating any database.
Create (or use) a directory for symbolic links to the devices you wish to use.
Then create your database, but instead of going to /dev/device, go to /
directory/symlink - When it comes time to move your devices, you shut down the
server, simply dd(1) the data from the old device to the new device, recreate
the symbolic links to the new device and restart the ASE. Simple as that.
Backups are a requisite in all cases, just in case.
Back to top
-------------------------------------------------------------------------------
1.1.8: Server naming and renaming
-------------------------------------------------------------------------------
There are three totally separate places where ASE names reside, causing much
confusion.
ASE Host Machine interfaces File
A master entry in here for server TEST will provide the network information
that the server is expected to listen on. The -S parameter to the dataserver
executable tells the server which entry to look for, so in the RUN_TEST file,
-STEST will tell the dataserver to look for the entry under TEST in the
interfaces file and listen on any network parameters specified by 'master'
entries.
TEST
master tcp ether hpsrv1 1200
query tcp ether hpsrv1 1200
Note that preceding the master/query entries there's a tab.
This is as far as the name TEST is used. Without further configuration the
server does not know its name is TEST, nor do any client applications.
Typically there will also be query entries under TEST in the local interfaces
file, and client programs running on the same machine as the server will pick
this connection information up. However, there is nothing to stop the query
entry being duplicated under another name entirely in the same interfaces file.
ARTHUR
query tcp ether hpsrv1 1200
isql -STEST or isql -SARTHUR will connect to the same server. The name is
simply a search parameter into the interfaces file.
Client Machine interfaces File
Again, as the server name specified to the client is simply a search parameter
for Open Client into the interfaces file, SQL.INI or WIN.INI the name is
largely irrelevant. It is often set to something that means something to the
users, especially where they might have a choice of servers to connect to. Also
multiple query entries can be set to point to the same server, possibly using
different network protocols. eg. if TEST has the following master entries on
the host machine:
TEST
master tli spx /dev/nspx/ \xC12082580000000000012110
master tcp ether hpsrv1 1200
Then the client can have a meaningful name:
ACCOUNTS_TEST_SERVER
query tcp ether hpsrv1 1200
or alternative protocols:
TEST_IP
query tcp ether hpsrv1 1200
TEST_SPX
query tli spx /dev/nspx/ \xC12082580000000000012110
sysservers
This system table holds information about remote ASEs that you might want to
connect to, and also provides a method of naming the local server.
Entries are added using the sp_addserver system procedure - add a remote server
with this format:
sp_addserver server_name, null, network_name
server_name is any name you wish to refer to a remote server by, but
network_name must be the name of the remote server as referenced in the
interfaces file local to your local server. It normally makes sense to make the
server_name the same as the network_name, but you can easily do:
sp_addserver LIVE, null, ACCTS_LIVE
When you execute for example, exec LIVE.master..sp_helpdb the local ASE will
translate LIVE to ACCTS_LIVE and try and talk to ACCTS_LIVE via the ACCTS_LIVE
entry in the local interfaces file.
Finally, a variation on the sp_addserver command:
sp_addserver LOCALSRVNAME, local
names the local server (after a restart). This is the name the server reports
in the errorlog at startup, the value returned by @@SERVERNAME, and the value
placed in Open Client server messages. It can be completely different from the
names in RUN_SRVNAME or in local or remote interfaces - it has no bearing on
connectivity matters.
Back to top
-------------------------------------------------------------------------------
1.1.9: How do I interpret the tli strings in the interface file?
-------------------------------------------------------------------------------
The tli string contained with Solaris interface files is a hex string
containing port and IP address. If you have an entry
SYBSRVR
master tli tcp /dev/tcp \x000204018196c4510000000000000000
Then it can be interpreted as follows:
x0002 no user interpretation (header info?)
0401 port number (1025 decimal)
81 first part of IP address (129 decimal)
96 second part of IP address (150 decimal)
c4 third part of IP address (196 decimal)
51 fourth part of IP address (81 decimal)
So, the above tli address is equivalent to
SYBSRVR
master tcp ether sybhost 1025
where sybhost's IP address is 129.150.196.81.
The following piece of Sybperl (courtesy of Michael Peppler) takes a tli entry
and returns the IP address and port number for each server in a Solaris'
interfaces file.
#!/usr/local/bin/perl -w
use strict;
my $server;
my @dat;
my ($port, $ip);
while(<>) {
next if /^\s*$/;
next if /^\s*\#/;
chomp;
if(/^\w/) {
$server = $_;
$server =~ s/\s*$//;
next;
}
@dat = split(' ', $_);
($port, $ip) = parseAddress($dat[4]);
print "$server - $dat[0] on port $port, host $ip\n";
}
sub parseAddress {
my $addr = shift;
my $port;
my $ip;
my (@arr) = (hex(substr($addr, 10, 2)),
hex(substr($addr, 12, 2)),
hex(substr($addr, 14, 2)),
hex(substr($addr, 16, 2)));
$port = hex(substr($addr, 6, 4));
$ip = join('.', @arr);
($port, $ip);
}
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-------------------------------------------------------------------------------
1.1.10: How can I tell the datetime my Server started?
-------------------------------------------------------------------------------
Method #1
The normal way would be to look at the errorlog, but this is not always
convenient or even possible. From a SQL session you find out the server startup
time to within a few seconds using:
select "Server Start Time" = crdate
from master..sysdatabases
where name = "tempdb"
Method #2
Another useful query is:
select * from sysengines
which gives the address and port number at which the server is listening.
Back to top
-------------------------------------------------------------------------------
1.1.11: Raw partitions or regular files?
-------------------------------------------------------------------------------
Hmmm... as always, this answer depends on the vendor's implementation on a
cooked file system for the ASE...
Performance Hit (synchronous vs asynchronous)
If on this platform, the ASE performs file system I/O synchronously then the
ASE is blocked on the read/write and throughput is decreased tremendously.
The way the ASE typically works is that it will issue an I/O (read/write) and
save the I/O control block and continue to do other work (on behalf of other
connections). It'll periodically poll the workq's (network, I/O) and resume
connections when their work has completed (I/O completed, network data
xmit'd...).
Performance Hit (bcopy issue)
Assuming that the file system I/O is asynchronous (this can be done on SGI), a
performance hit may be realized when bcopy'ing the data from kernel space to
user space.
Cooked I/O typically (again, SGI has something called directed I/O which allows
I/O to go directly to user space) has to go from disk, to kernel buffers and
from kernel buffers to user space; on a read. The extra layer with the kernel
buffers is inherently slow. The data is moved from kernel buffers to/from user
space using bcopy(). On small operations this typically isn't that much of an
issue but in a RDBMS scenario the bcopy() layer is a significant performance
hit because it's done so often...
Performance Gain!
It's true, using file systems, at times you can get performance gains assuming
that the ASE on your platform does the I/O asynchronously (although there's a
caveat on this too... I'll cover that later on).
If your machine has sufficient memory and extra CPU capacity, you can realize
some gains by having writes return immediately because they're posted to
memory. Reads will gain from the anticipatory fetch algorithm employed by most
O/S's.
You'll need extra memory to house the kernel buffered data and you'll need
extra CPU capacity to allow bdflush() to write the dirty data out to disk...
eventually... but with everything there's a cost: extra memory and free CPU
cycles.
One argument is that instead of giving the O/S the extra memory (by leaving it
free) to give it to the ASE and let it do its caching... but that's a different
thread...
Data Integrity and Cooked File System
If the Sybase ASE is not certified to be used over a cooked file system,
because of the nature of the kernel buffering (see the section above) you may
face database corruption by using cooked file system anyway. The ASE thinks
that it has posted its changes out to disk but in reality it has gone only to
memory. If the machine halts without bdflush() having a chance to flush memory
out to disk, your database may become corrupted.
Some O/S's allow cooked files to have a write through mode and it really
depends if the ASE has been certified on cooked file systems. If it has, it
means that when the ASE opens a device which is on a file system, it fcntl()'s
the device to write-through.
When to use cooked file system?
I typically build my tempdb on cooked file system and I don't worry about data
integrity because tempdb is rebuilt every time your ASE/SQL Server is rebooted.
Back to top
-------------------------------------------------------------------------------
1.1.12: Is Sybase Y2K (Y2000) compliant?
-------------------------------------------------------------------------------
Sybase is year 2000 compliant at specific revisions of each product. Full
details are available at http://www.sybase.com, specifically (as these links
will undoubtedly change):
http://www.sybase.com/success/inc/corpinfo/year2000_int.html
http://www.sybase.com/Company/corpinfo/year2000_matrix.html
Note: Since we have made it to 2000 more or less intact, I see no reason to
include this question. I plan to remove with the next release of the FAQ. If
you feel strongly about leaving it in then let me know.
Back to top
-------------------------------------------------------------------------------
1.1.13 How Can I Run the ASE Upgrade Manually?
-------------------------------------------------------------------------------
How to Run the ASE Upgrade Manually
This document describes the steps required to perform a manual upgrade for ASE
from release 4.x or 10.0x to release 11.02. In most cases, however, you should
use sybinit to perform the upgrade.
BE SURE TO HAVE GOOD BACKUPS BEFORE STARTING THIS PROCEDURE.
1. Use release 11.0x sybinit to run the pre-eligibility test and Check
Reserved words. Make any necessary changes that are mentioned in the
sybinit log. The sybinit log is located in $SYBASE/init/logs/logxxxx.yyy.
2. Use isql to connect to the 4.x or 10.0x ASE and do the following tasks:
a. Turn on option to allow updates to system tables:
1> sp_configure "allow updates", 1
2> go
b. Checkpoint all databases:
1> use "dbname"
2> go
1> checkpoint
2> go
c. Shutdown the 4.x or 10.0x ASE.
1> shutdown
2> go
3. Copy the interfaces file to the release 11.0x directory.
4. Set the environment variable SYBASE to the release 11.0x directory.
5. Copy the runserver file to the release 11.0x $SYBASE/install directory.
6. Edit the $SYBASE/install/RUN_SYBASE (runserver file) to change the path
from the 4.x or 10.x dataserver directory to the new release 11.0x
directory.
7. Start ASE using the new runserver file.
% startserver -f$SYBASE/install/RUN_SYBASE
8. Run the upgrade program:
UNIX: $SYBASE/upgrade/upgrade -S"servername" -P"sapassword" > $SYBASE/init/
logs/mylog.log 2>&1 VMS: SYBASE_SYSTEM[SYBASE.UPGRADE]upgrade /password=
"sa_password" /servername="servername"
9. Shut down SQL server after a successful upgrade.
% isql -Usa -Pxxx
-SSYBASE
1> shutdown
2> go
10. Start ASE using the release 11.0x runserver file.
% startserver -f$SYBASE/install/RUN_SYBASE
11. Create the sybsystemprocs device and database if upgrading from 4.9.x. You
should create a 21mb sybsystemprocs device and database.
a. Use the disk init command to create the sybsytemprocs device and
database manually, for example:
disk init name = "sybprocsdev", physname="/dev/sybase/rel1102/
sybsystemprocs.dat", vdevno=4, size=10752 go To check to see which vdevno
is available: type 1> select distinct low/16777216 from sysdevices 2> order
by low 3> go A sample create database command: create database
sybsystemprocs on sybprocsdev=21 go Please refer to the "Sybase ASE
Reference Manual", for more information on these commands.
12. Run the installmaster and installmodel scripts:
UNIX: %isql -Usa -Psapassword -i$SYBASE/scripts/installmaster
UNIX: %isql -Usa -Psapassword -i$SYBASE/scripts/installmodel
VMS: $isql /user="sa" /password="sapass"
/input="[sybase_system.scripts]installm aster"
VMS: $isql /user="sa" /password="sapass"
/input="[sybase_system.scripts]installm odel"
13. If you upgraded from ASE 4.9.2, you will need to run sp_remap to remap the
compiled objects. Sp_remap remaps stored procedures, triggers, rules,
defaults, or views to be compatible with the current release of ASE. Please
refer to the Reference Manual Volume II for more information on the
sp_remap command.
The syntax for sp_remap:
sp_remap object_name
If you are upgrading to ASE 11.0.x and the upgrade process failed when using
sybinit, you can invoke sybinit and choose remap query tress from the upgrade
menu screen. This is a new option that is added, after a failed upgrade.
Back to top
-------------------------------------------------------------------------------
1.1.14 We have lost the sa password, what can we do?
-------------------------------------------------------------------------------
Remember Douglas Adams famous quote "Don't panic" is the first thing!
I know that most people use the 'sa' account all of the time, which is fine if
there is only ever one dba administering the system. If you have more than one
person accessing the server using the 'sa' account, consider using sa_role
enabled accounts and disabling the 'sa' account. Funnily enough, this is
obviously what Sybase think because it is one of the questions in the
certification exams.
If you see that someone is logged using the 'sa' account or is using an account
with 'sa_role' enabled, then you can do the following:
sp_configure "allow updates to system tables",1
go
update syslogins set password=null where name = 'sa'
go
sp_password null,newPassword
go
You must rememeber to reset the password before exiting isql or sqsh. I thought
that setting it to null would be enough, and exited isql thinking that I would
be able to get in with a null password. Take it from me that the risk is not
worth it. It failed for me and I had to kill the dataserver and get a new
password. I just tried the above method and it works fine.
If you have a user with sso_role enabled, login with that account and change
the 'sa' password that way. It is often a good idea to have a separate site
security officer, just to get you out of this sticky situation. Certainly stops
you looking an idiot in managements eyes for having to reboot production
because you have locked yourself out!
OK, so we have got to the point where there are no accounts with sufficient
priviledges to allow you to change the 'sa' account password. (You are sure
about that, since the next part can cause data loss, so have another quick
look.) We now need to some more drastic stuff.
If the server is actually running, then you need to stop it. We know that the
only accounts that can stop the server in a nice manner are not available, so
it has to be some sort of kill. You can try:
kill -SIGTERM
or
kill -15
(they are identical) which is designed to be caught by ASE, which then performs
the equivalent of shutdown with nowait. If ASE does not die, and you should
give it a little while to catch and act on the signal, then you might have to
try other measures, which is probably kill -9. Note that if you have tables
with identity columns, most of these will jump alarmingly, unless you are using
ASE 12.5 and the identity interval is set to 1.
Once down, edit the RUN_SERVER file ( RUN_SERVER.bat on NT) and add "-psa" (it
is important not to leave a space between the"-p" and the "sa", and that it is
all lower-case) to the end of the dataserver or sqlsrvr.exe line. You will end
up with a file that looks a bit like:
#!/bin/sh
#
# Adaptive Server name: N_UTSIRE
# Master device path: /data/sybase/databases/N_UTSIRE/master.dat
# Error log path: /opt/sybase-11.9.2/install/N_UTSIRE.log
# Directory for shared memory files: /opt/sybase-11.9.2
#
# Regenerate sa password -psa
#
/opt/sybase-11.9.2/bin/dataserver \
-sN_UTSIRE \
-d/data/sybase/databases/N_UTSIRE/master.dat \
-e/opt/sybase-11.9.2/install/N_UTSIRE.log \
-M/opt/sybase-11.9.2 -psa \
(I add the line mentioning the regenerate, so that if I need to do this in a
moment of extreme pressure it is there in front of my nose.
Now, start the server again and you should see the following on the screen:
00:00000:00001:2001/05/26 18:29:21.39 server 'bin_iso_1' (ID = 50)
00:00000:00001:2001/05/26 18:29:21.39 server on top of default character set:
00:00000:00001:2001/05/26 18:29:21.39 server 'iso_1' (ID = 1).
00:00000:00001:2001/05/26 18:29:21.39 server Loaded default Unilib conversion handle.
New SSO password for sa:tmfyrkdwpibung
Note that it is not written to the log file, so keep your eyes peeled.
On NT you will have to start the server from the command line and not use
Sybase Central or the control panel.
Obviously, you will want to change the password to something much more
memorable as soon as possible.
Remember to remove the "-psa" from the "RUN" file before you start the server
again or else the password will be changed again for you.
Back to top
-------------------------------------------------------------------------------
1.1.15 How do I set a password to be null?
-------------------------------------------------------------------------------
Since ASE 11 (I cannot remember if it was with the very first release of 11,
but certainly not before) the password column in syslogins has been encrypted.
Setting this column to NULL does not equate to that login having a NULL
password. A NULL password still requires the correct binary string to be in
place.
In release 12 and above, set the minimum password length to be 0 using
sp_configure and give that account a null password, and all should be fine.
Before 12, it is not possible to set the minimum password length, so the direct
approach is not possible. So, update the relevant record in syslogins setting
the password column to be the same as that of an account with a NULL password
already.
How does one get the correct binary value? When a new ASE is built, the 'sa'
account has a NULL password to start with. Setting an account to have the same
binary value as such an 'sa' account should work. Remember that the binary
string is going to be specific to the operating system and the exact release of
ASE etc. Obviously, if you have set the password of your 'sa' accounts to be
something other than NULL (sensible move), then you are going to have to build
yourself a dummy server just to get the correct string. If this is important to
you, then you may wish to store the value somewhere safe once you have
generated it.
Yet another method would be to simply insert the correct hex string into the
password column. Rob Verschoor has a very nice stored proc on his site called
sp_blank_password to allow you to do just this. Go to http://www.sypron.nl/
blankpwd.html .
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-------------------------------------------------------------------------------
1.1.16: Does Sybase support Row Level Locking?
-------------------------------------------------------------------------------
With Adaptive Server Enterprise 11.9 Sybase introduced row level locking into
its product. In fact it went further than that, it introduced 3 different
locking levels:
* All Pages Locking
This is the scheme that is implemented in all servers prior to 11.9. Here
locks are taken out at the page level, which may included many rows. The
name refers to the fact that all of the pages in any data manipulation
statement are locked, both data and index.
* Data Page Locking
The other two locking schemes are bundled together under the title Data
Page Locking, refering to the fact that only data pages are ever locked in
the conventional sense. Data Page Locking is divided into two categories
+ Data Only Locking
This locking scheme still locks a page at a time, including all of the
rows contained within that page, but uses a new mechanism, called
latches, to lock index pages for the shortest amount of time. One of
the consequences of this scheme is that it does not update index
pages. In order to support this Sybase has introduced a new concept,
forwarded rows. These are rows that have had to move because they have
grown beyond space allowed for them on the page they were created. 2002
bytes per page.
+ Row Level Locking
Just as it sounds, the lock manager only locks the row involved in the
operation.
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-------------------------------------------------------------------------------
1.1.17: What platforms does ASE run on?
-------------------------------------------------------------------------------
Sybase has an excellent lookup page that tells you all of the releases that
Sybase has certifies as running on a particular platform. Got to http://
ohno.sybase.com/cgi-bin/ws.exe/cert/ase_cert.hts .
Back to top
-------------------------------------------------------------------------------
1.1.18: How do I backup databases > 64G on ASE prior to 12.x?
-------------------------------------------------------------------------------
As you are all well aware, prior to version of ASE 12, dumping large databases
was a real pain. Tape was the only option for anything greater than 64 gig.
This was because only 32 dump devices, or stripes, were supported, and since
file based stripes were restricted to no more than 2 gig, the total amount of
data that could be dumped was <= 32 * 2 = 64G.
With the introduction of ASE 12, the number of stripes was increased
Back to top
-------------------------------------------------------------------------------
User Database Administration # ASE FAQ
User Contributions:Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Part9 - Part10 - Part11 - Part12 - Part13 - Part14 - Part15 - Part16 - Part17 - Part18 - Part19 [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: dowen@midsomer.org (David Owen)
Last Update March 27 2014 @ 02:11 PM
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