Re: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs)
Thanks to all of you for the input.
The suggestion of sending the log files and
checking
the size of the resulting Shareplex output is very
good.
I talked today with the sales person and she will put me
in contact
with the technical people in ACS (Quest representative
in Israel).
Will update you later.
Thanks again.
Yechiel AdarMehish
- Original Message -
From:
Aponte, Tony
To: Multiple recipients of list ORACLE-L
Sent: Friday, June 14, 2002 7:41 PM
Subject: RE: I/O contention with external
process reading the oracle logs (online redo logs)
Actually, for us the percentage is lower since the
OLTP application we're using itfor is heavily indexed (with the
exception of single SQL that updates many rows.) It's one of those
claims that is usually followed by "your mileage may
vary."
Tony
-Original Message-From: Tim Gorman [mailto:[EMAIL PROTECTED]]Sent:
Thursday, June 13, 2002 9:23 PMTo: Multiple recipients of list
ORACLE-LSubject: Re: I/O contention with external process reading
the oracle logs (online redo logs)
It shouldn't need to be a "theoretical" or
"statistical" claim at all. A prospective customer should be able to
ship a few archived redo log files (the more the better!) to Quest and have
them run it through that part of SharePlex that will read the redo and
produce SQL. I'm surprised they haven't suggested it already...
:-)
- Original Message -
From:
Aponte, Tony
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Sent: Thursday, June 13, 2002 8:47
AM
Subject: RE: I/O contention with
external process reading the oracle logs (online redo logs)
I think Yechiel is referring to a statistical claim by
Quest that only 30% of the redo stream is usable in re-assembling the SQL
statement. The rest is like you suspect, index maintenance, rbs
segment maintenance, etc. But you are right to point out (so
right) that a multi-row update by a single SQL on the source results in
individual updates on the target. That's a little nugget that the
marketing folks left out of their 30% claim.
Tony
-Original Message- From:
Tim Gorman [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, June 12, 2002 10:48 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the
oracle logs (online redo logs)
Just curious, why do you think replication will be less
bandwidth? Are you replicating only certain
schemas/accounts and not the entire database?
Is Quest asserting that shipping the SQL statements are
more "compact" than shipping the redo? That
could be possible, but I'm quite certain that it is near thing, unless the heavily-modified tables in the app have been
indexed with a heavy hand. For example,
unless SharePlex has some remarkable logic, it
won't be "coalescing" a million-row update into the single SQL
statement that spawned it, which ironically
Oracle's advanced replication might be able to
do! Instead, they'll need to reverse-engineer individual
UPDATE statements for each row, just like Oracle's
LogMiner. The only circumstances under which
I can imagine individual row-level SQL statements being more compact that the redo resulting from them is when there
are lots of large indices on the table...
---
On another note, the 9iR2 "logical standby" feature is a
direct knockoff of SharePlex, in that the RDBMS
ships the SQL instead of the redo logfile, so the
characteristics should be very similar. Of course, 9iR2 is very new
and *very* raw at the moment, while SharePlex has
been around for something like 5-6 years already
(i.e. eons!), so that should be a strong consideration. But, when I last worked with SharePlex (3.0, I think), it had lots
of bad habits like demanding "DBA" role to be
granted to it's account both for installation as
well as run-time, setting SETUID on executables owned by "root" (17-18 of them! drove the UNIX sysadmins insane! with
good reason); just a lot of lazy development
practices that I hope have been fixed...
- Original Message - To:
"Multiple recipients of list ORACLE-L" [EMAIL PROTECTED]
Sent: Wednesday, June 12, 2002 8:48 AM (online redo logs)
Hello Tim and Rachel There is band width problem. The
line is 256K (we are checking upgrade to
512k). The database, during peek time produce
10MB of logs every 2-3 mi
RE: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs) My experience is that they do nothing for free. -Original Message- From: [EMAIL PROTECTED]@SUNGARD On Behalf Of Tim Gorman [EMAIL PROTECTED] Sent: Thursday, June 13, 2002 9:23 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the oracle logs (online redo logs) It shouldn't need to be a theoretical or statistical claim at all. A prospective customer should be able to ship a few archived redo log files (the more the better!) to Quest and have them run it through that part of SharePlex that will read the redo and produce SQL. I'm surprised they haven't suggested it already... :-) -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs) who does? :-) - Original Message - From: [EMAIL PROTECTED] To: Multiple recipients of list ORACLE-L Sent: Friday, June 14, 2002 6:28 AM Subject: RE: I/O contention with external process reading the oracle logs (online redo logs) My experience is that they do nothing for free. -Original Message- From: [EMAIL PROTECTED]@SUNGARD On Behalf Of "Tim Gorman" [EMAIL PROTECTED] Sent: Thursday, June 13, 2002 9:23 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the oracle logs (online redo logs) It shouldn't need to be a "theoretical" or "statistical" claim at all. A prospective customer should be able to ship a few archived redo log files (the more the better!) to Quest and have them run it through that part of SharePlex that will read the redo and produce SQL. I'm surprised they haven't suggested it already... :-)-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs) Quest. -Original Message- From: [EMAIL PROTECTED]@SUNGARD On Behalf Of Tim Gorman [EMAIL PROTECTED] Sent: Friday, June 14, 2002 10:38 AM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the oracle logs (online redo logs) who does? :-) - Original Message - From: [EMAIL PROTECTED] File: mailto:[EMAIL PROTECTED] To: Multiple recipients of list ORACLE-L File: mailto:[EMAIL PROTECTED] Sent: Friday, June 14, 2002 6:28 AM Subject: RE: I/O contention with external process reading the oracle logs (online redo logs) My experience is that they do nothing for free. -Original Message- From: [EMAIL PROTECTED]@SUNGARD File: mailto:[EMAIL PROTECTED]@SUNGARD On Behalf Of Tim Gorman [EMAIL PROTECTED] File: mailto:[EMAIL PROTECTED] Sent: Thursday, June 13, 2002 9:23 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the oracle logs (online redo logs) It shouldn't need to be a theoretical or statistical claim at all. A prospective customer should be able to ship a few archived redo log files (the more the better!) to Quest and have them run it through that part of SharePlex that will read the redo and produce SQL. I'm surprised they haven't suggested it already... :-) -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs)
Actually, for us the percentage is lower since the OLTP
application we're using itfor is heavily indexed (with the exception
of single SQL that updates many rows.) It's one of those claims that is
usually followed by "your mileage may vary."
Tony
-Original Message-From: Tim Gorman
[mailto:[EMAIL PROTECTED]]Sent: Thursday, June 13, 2002 9:23
PMTo: Multiple recipients of list ORACLE-LSubject: Re:
I/O contention with external process reading the oracle logs (online redo
logs)
It shouldn't need to be a "theoretical" or
"statistical" claim at all. A prospective customer should be able to
ship a few archived redo log files (the more the better!) to Quest and have
them run it through that part of SharePlex that will read the redo and produce
SQL. I'm surprised they haven't suggested it already...
:-)
- Original Message -
From:
Aponte, Tony
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Sent: Thursday, June 13, 2002 8:47
AM
Subject: RE: I/O contention with
external process reading the oracle logs (online redo logs)
I think Yechiel is referring to a statistical claim by Quest
that only 30% of the redo stream is usable in re-assembling the SQL
statement. The rest is like you suspect, index maintenance, rbs
segment maintenance, etc. But you are right to point out (so
right) that a multi-row update by a single SQL on the source results in
individual updates on the target. That's a little nugget that the
marketing folks left out of their 30% claim.
Tony
-Original Message- From: Tim
Gorman [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, June 12, 2002 10:48 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the
oracle logs (online redo logs)
Just curious, why do you think replication will be less
bandwidth? Are you replicating only certain
schemas/accounts and not the entire database?
Is Quest asserting that shipping the SQL statements are more
"compact" than shipping the redo? That could
be possible, but I'm quite certain that it is near
thing, unless the heavily-modified tables in the app have been
indexed with a heavy hand. For example, unless
SharePlex has some remarkable logic, it won't be
"coalescing" a million-row update into the single SQL statement
that spawned it, which ironically Oracle's advanced
replication might be able to do! Instead,
they'll need to reverse-engineer individual UPDATE statements for each row, just like Oracle's LogMiner. The
only circumstances under which I can imagine
individual row-level SQL statements being more
compact that the redo resulting from them is when there are lots
of large indices on the table...
---
On another note, the 9iR2 "logical standby" feature is a
direct knockoff of SharePlex, in that the RDBMS
ships the SQL instead of the redo logfile, so the
characteristics should be very similar. Of course, 9iR2 is very new
and *very* raw at the moment, while SharePlex has
been around for something like 5-6 years already
(i.e. eons!), so that should be a strong consideration. But, when I last worked with SharePlex (3.0, I think), it had lots of
bad habits like demanding "DBA" role to be granted
to it's account both for installation as well as
run-time, setting SETUID on executables owned by "root" (17-18 of them! drove the UNIX sysadmins insane! with
good reason); just a lot of lazy development
practices that I hope have been fixed...
- Original Message - To:
"Multiple recipients of list ORACLE-L" [EMAIL PROTECTED]
Sent: Wednesday, June 12, 2002 8:48 AM (online redo logs)
Hello Tim and Rachel There is band width problem. The
line is 256K (we are checking upgrade to
512k). The database, during peek time produce
10MB of logs every 2-3 minutes. On this line it
will take 7-8 minutes to pass 10MB if the line was dedicate and it is not dedicated.
Upgrading the line to
more then 512K need E1 at least and it is expansive. Since replication will need less
band width we are checking it. To return to my original question:
Quest Shareplex - Any success stories?
Why use this and not replication? Ant performance tests between Shareplex and Oracle
replication?
Yechiel Adar Mehish - Original Message - To:
Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Monday, June 10, 2002 4:33 AM (online redo logs) and if you need the remote
site to support users, you could use the
logical standby feature of 9i
RE: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs) I think Yechiel is referring to a statistical claim by Quest that only 30% of the redo stream is usable in re-assembling the SQL statement. The rest is like you suspect, index maintenance, rbs segment maintenance, etc. But you are right to point out (so right) that a multi-row update by a single SQL on the source results in individual updates on the target. That's a little nugget that the marketing folks left out of their 30% claim. Tony -Original Message- From: Tim Gorman [mailto:[EMAIL PROTECTED]] Sent: Wednesday, June 12, 2002 10:48 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the oracle logs (online redo logs) Just curious, why do you think replication will be less bandwidth? Are you replicating only certain schemas/accounts and not the entire database? Is Quest asserting that shipping the SQL statements are more compact than shipping the redo? That could be possible, but I'm quite certain that it is near thing, unless the heavily-modified tables in the app have been indexed with a heavy hand. For example, unless SharePlex has some remarkable logic, it won't be coalescing a million-row update into the single SQL statement that spawned it, which ironically Oracle's advanced replication might be able to do! Instead, they'll need to reverse-engineer individual UPDATE statements for each row, just like Oracle's LogMiner. The only circumstances under which I can imagine individual row-level SQL statements being more compact that the redo resulting from them is when there are lots of large indices on the table... --- On another note, the 9iR2 logical standby feature is a direct knockoff of SharePlex, in that the RDBMS ships the SQL instead of the redo logfile, so the characteristics should be very similar. Of course, 9iR2 is very new and *very* raw at the moment, while SharePlex has been around for something like 5-6 years already (i.e. eons!), so that should be a strong consideration. But, when I last worked with SharePlex (3.0, I think), it had lots of bad habits like demanding DBA role to be granted to it's account both for installation as well as run-time, setting SETUID on executables owned by root (17-18 of them! drove the UNIX sysadmins insane! with good reason); just a lot of lazy development practices that I hope have been fixed... - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Wednesday, June 12, 2002 8:48 AM (online redo logs) Hello Tim and Rachel There is band width problem. The line is 256K (we are checking upgrade to 512k). The database, during peek time produce 10MB of logs every 2-3 minutes. On this line it will take 7-8 minutes to pass 10MB if the line was dedicate and it is not dedicated. Upgrading the line to more then 512K need E1 at least and it is expansive. Since replication will need less band width we are checking it. To return to my original question: Quest Shareplex - Any success stories? Why use this and not replication? Ant performance tests between Shareplex and Oracle replication? Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Monday, June 10, 2002 4:33 AM (online redo logs) and if you need the remote site to support users, you could use the logical standby feature of 9iR2, which generates SQL statements to be applied and allows the database to be open and active. --- Tim Gorman [EMAIL PROTECTED] wrote: why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome
Re: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs) It shouldn't need to be a "theoretical" or "statistical" claim at all. A prospective customer should be able to ship a few archived redo log files (the more the better!) to Quest and have them run it through that part of SharePlex that will read the redo and produce SQL. I'm surprised they haven't suggested it already... :-) - Original Message - From: Aponte, Tony To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Thursday, June 13, 2002 8:47 AM Subject: RE: I/O contention with external process reading the oracle logs (online redo logs) I think Yechiel is referring to a statistical claim by Quest that only 30% of the redo stream is usable in re-assembling the SQL statement. The rest is like you suspect, index maintenance, rbs segment maintenance, etc. But you are right to point out (so right) that a multi-row update by a single SQL on the source results in individual updates on the target. That's a little nugget that the marketing folks left out of their 30% claim. Tony -Original Message- From: Tim Gorman [mailto:[EMAIL PROTECTED]] Sent: Wednesday, June 12, 2002 10:48 PM To: Multiple recipients of list ORACLE-L Subject: Re: I/O contention with external process reading the oracle logs (online redo logs) Just curious, why do you think replication will be less bandwidth? Are you replicating only certain schemas/accounts and not the entire database? Is Quest asserting that shipping the SQL statements are more "compact" than shipping the redo? That could be possible, but I'm quite certain that it is near thing, unless the heavily-modified tables in the app have been indexed with a heavy hand. For example, unless SharePlex has some remarkable logic, it won't be "coalescing" a million-row update into the single SQL statement that spawned it, which ironically Oracle's advanced replication might be able to do! Instead, they'll need to reverse-engineer individual UPDATE statements for each row, just like Oracle's LogMiner. The only circumstances under which I can imagine individual row-level SQL statements being more compact that the redo resulting from them is when there are lots of large indices on the table... --- On another note, the 9iR2 "logical standby" feature is a direct knockoff of SharePlex, in that the RDBMS ships the SQL instead of the redo logfile, so the characteristics should be very similar. Of course, 9iR2 is very new and *very* raw at the moment, while SharePlex has been around for something like 5-6 years already (i.e. eons!), so that should be a strong consideration. But, when I last worked with SharePlex (3.0, I think), it had lots of bad habits like demanding "DBA" role to be granted to it's account both for installation as well as run-time, setting SETUID on executables owned by "root" (17-18 of them! drove the UNIX sysadmins insane! with good reason); just a lot of lazy development practices that I hope have been fixed... - Original Message - To: "Multiple recipients of list ORACLE-L" [EMAIL PROTECTED] Sent: Wednesday, June 12, 2002 8:48 AM (online redo logs) Hello Tim and Rachel There is band width problem. The line is 256K (we are checking upgrade to 512k). The database, during peek time produce 10MB of logs every 2-3 minutes. On this line it will take 7-8 minutes to pass 10MB if the line was dedicate and it is not dedicated. Upgrading the line to more then 512K need E1 at least and it is expansive. Since replication will need less band width we are checking it. To return to my original question: Quest Shareplex - Any success stories? Why use this and not replication? Ant performance tests between Shareplex and Oracle replication? Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Monday, June 10, 2002 4:33 AM (online redo logs) and if you need the remote site to support users, you could use the logical standby feature of 9iR2, which generates SQL statements to be applied and allows the database to be open and active. --- Tim Gorman [EMAIL PROTECTED] wrote:why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message -To: "Multiple recipients of list ORACLE-L" [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous rep
Re: I/O contention with external process reading the oracle logs (online redo logs)
Hello Tim and Rachel There is band width problem. The line is 256K (we are checking upgrade to 512k). The database, during peek time produce 10MB of logs every 2-3 minutes. On this line it will take 7-8 minutes to pass 10MB if the line was dedicate and it is not dedicated. Upgrading the line to more then 512K need E1 at least and it is expansive. Since replication will need less band width we are checking it. To return to my original question: Quest Shareplex - Any success stories? Why use this and not replication? Ant performance tests between Shareplex and Oracle replication? Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Monday, June 10, 2002 4:33 AM (online redo logs) and if you need the remote site to support users, you could use the logical standby feature of 9iR2, which generates SQL statements to be applied and allows the database to be open and active. --- Tim Gorman [EMAIL PROTECTED] wrote: why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome. TIA Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Thursday, June 06, 2002 4:32 PM (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will have. * I would find it HARD to believe that only ONE process can read a block at a time. If this were true, then OLTP system would FAIL miserably! Anyone have any ideas/comments regarding the OS and Oracle interaction I mean are not the logs at this pointa UNIX file? and can't multiple processes read a single unix file without bringing the whole system to its knees? Also, I am NOT knocking the techincal support, but I believe that the opinion was formulated on an incorrect assumption on the
Re: I/O contention with external process reading the oracle logs (online redo logs)
Shareplex reads the log files so if you can't get the log files over the existing line, Shareplex can't read them. have you considered using an NFS mounted disk for your archive log directory? or a process that copies the archived logs to the nfs mounted disk on the primary and a another process that copies them off the nfs mounted disk on the secondary? I had to do something like that when I worked with Sybase, back in the 4.7 days, so that I could backup the log files realtime. --- Yechiel Adar [EMAIL PROTECTED] wrote: Hello Tim and Rachel There is band width problem. The line is 256K (we are checking upgrade to 512k). The database, during peek time produce 10MB of logs every 2-3 minutes. On this line it will take 7-8 minutes to pass 10MB if the line was dedicate and it is not dedicated. Upgrading the line to more then 512K need E1 at least and it is expansive. Since replication will need less band width we are checking it. To return to my original question: Quest Shareplex - Any success stories? Why use this and not replication? Ant performance tests between Shareplex and Oracle replication? Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Monday, June 10, 2002 4:33 AM (online redo logs) and if you need the remote site to support users, you could use the logical standby feature of 9iR2, which generates SQL statements to be applied and allows the database to be open and active. --- Tim Gorman [EMAIL PROTECTED] wrote: why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome. TIA Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Thursday, June 06, 2002 4:32 PM (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will
Re: I/O contention with external process reading the oracle logs (online redo logs)
Just curious, why do you think replication will be less bandwidth? Are you replicating only certain schemas/accounts and not the entire database? Is Quest asserting that shipping the SQL statements are more compact than shipping the redo? That could be possible, but I'm quite certain that it is near thing, unless the heavily-modified tables in the app have been indexed with a heavy hand. For example, unless SharePlex has some remarkable logic, it won't be coalescing a million-row update into the single SQL statement that spawned it, which ironically Oracle's advanced replication might be able to do! Instead, they'll need to reverse-engineer individual UPDATE statements for each row, just like Oracle's LogMiner. The only circumstances under which I can imagine individual row-level SQL statements being more compact that the redo resulting from them is when there are lots of large indices on the table... --- On another note, the 9iR2 logical standby feature is a direct knockoff of SharePlex, in that the RDBMS ships the SQL instead of the redo logfile, so the characteristics should be very similar. Of course, 9iR2 is very new and *very* raw at the moment, while SharePlex has been around for something like 5-6 years already (i.e. eons!), so that should be a strong consideration. But, when I last worked with SharePlex (3.0, I think), it had lots of bad habits like demanding DBA role to be granted to it's account both for installation as well as run-time, setting SETUID on executables owned by root (17-18 of them! drove the UNIX sysadmins insane! with good reason); just a lot of lazy development practices that I hope have been fixed... - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Wednesday, June 12, 2002 8:48 AM (online redo logs) Hello Tim and Rachel There is band width problem. The line is 256K (we are checking upgrade to 512k). The database, during peek time produce 10MB of logs every 2-3 minutes. On this line it will take 7-8 minutes to pass 10MB if the line was dedicate and it is not dedicated. Upgrading the line to more then 512K need E1 at least and it is expansive. Since replication will need less band width we are checking it. To return to my original question: Quest Shareplex - Any success stories? Why use this and not replication? Ant performance tests between Shareplex and Oracle replication? Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Monday, June 10, 2002 4:33 AM (online redo logs) and if you need the remote site to support users, you could use the logical standby feature of 9iR2, which generates SQL statements to be applied and allows the database to be open and active. --- Tim Gorman [EMAIL PROTECTED] wrote: why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome. TIA Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Thursday, June 06, 2002 4:32 PM (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams
Re: I/O contention with external process reading the oracle logs (online redo logs)
Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome. TIA Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Thursday, June 06, 2002 4:32 PM (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will have. * I would find it HARD to believe that only ONE process can read a block at a time. If this were true, then OLTP system would FAIL miserably! Anyone have any ideas/comments regarding the OS and Oracle interaction I mean are not the logs at this pointa UNIX file? and can't multiple processes read a single unix file without bringing the whole system to its knees? Also, I am NOT knocking the techincal support, but I believe that the opinion was formulated on an incorrect assumption on the operating system and Oracle. Thoughts/comments? Thanks in advance. Hannah -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Yechiel Adar INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: I/O contention with external process reading the oracle logs (online redo logs)
why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome. TIA Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Thursday, June 06, 2002 4:32 PM (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will have. * I would find it HARD to believe that only ONE process can read a block at a time. If this were true, then OLTP system would FAIL miserably! Anyone have any ideas/comments regarding the OS and Oracle interaction I mean are not the logs at this pointa UNIX file? and can't multiple processes read a single unix file without bringing the whole system to its knees? Also, I am NOT knocking the techincal support, but I believe that the opinion was formulated on an incorrect assumption on the operating system and Oracle. Thoughts/comments? Thanks in advance. Hannah -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Yechiel Adar INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line
Re: I/O contention with external process reading the oracle logs (online redo logs)
and if you need the remote site to support users, you could use the logical standby feature of 9iR2, which generates SQL statements to be applied and allows the database to be open and active. --- Tim Gorman [EMAIL PROTECTED] wrote: why wouldn't you consider simply using the standby database feature? do you need the remote site to support users also? - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 AM (online redo logs) Hello All I just had a meeting today about replication. The situations is: One master db that is currently replicated (master to master synchronous replication) to a second DB. Both machines are NT and the is a direct cable connection between the network cards on both machines. However, this solves the problem of machine failure but does not cover the full disaster recovery as both machines are in the same room. In case of fire both machines will be destroyed. We are thinking about adding asynchronous replication to replicate the changes across wan to a remote site. The problem is that this will load the production system and the network link (wan is expensive), as the system generates during peek time 10MB of archive logs every 2-3 minutes. I saw that some of you are using Quest Shareplex. Can you share your reasons, success stories etc? Benchmarks results will be very welcome. TIA Yechiel Adar Mehish - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Thursday, June 06, 2002 4:32 PM (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will have. * I would find it HARD to believe that only ONE process can read a block at a time. If this were true, then OLTP system would FAIL miserably! Anyone have any ideas/comments regarding the OS and Oracle interaction I mean are not the logs at this pointa UNIX file? and can't multiple processes read a single unix file without bringing the whole system to its knees? Also, I am NOT knocking the techincal support, but I believe that the opinion was formulated on an incorrect assumption on the operating system and Oracle. Thoughts/comments? Thanks in advance. Hannah -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Yechiel Adar INET: [EMAIL
RE: I/O contention with external process reading the oracle logs (online redo logs)
NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will have. * I would find it HARD to believe that only ONE process can read a block at a time. If this were true, then OLTP system would FAIL miserably! Anyone have any ideas/comments regarding the OS and Oracle interaction I mean are not the logs at this pointa UNIX file? and can't multiple processes read a single unix file without bringing the whole system to its knees? Also, I am NOT knocking the techincal support, but I believe that the opinion was formulated on an incorrect assumption on the operating system and Oracle. Thoughts/comments? Thanks in advance. Hannah -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: I/O contention with external process reading the oracle logs (online redo logs)
Title: RE: I/O contention with external process reading the oracle logs (online redo logs) I think they are alluding to UNIX file system contention. If the redo logs are in regular file systems (not raw, Veritas Quick I/O, etc.) then UNIX (at least in my Solaris environment) needs to lock the file for each of the Shareplex capture processes, in addition to LGWR. There will also be some contention inside the source database that is not mentioned in their response. Shareplex needs to query the source table to get the primary key value for the row that changed. It does it using the rowid that was scraped off the redo log. It then uses the primary key value from the source table to build the insert statement for the target. In our installation this process amounts to 5% of the CPU used by this session statistic. Although the blocks needed are still in the buffer cache, there is some serialization that has to occur to fulfill the logical I/O. BTW, in 9i the logical standby implementation includes the primary key value in the redo stream after extended logging is activated. This relieves the source from the backwards-looking access for the primary key as done by Shareplex. I doubt that the performance gain of extended logging is totally free though. HTH. Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 06, 2002 10:32 AM To: Multiple recipients of list ORACLE-L Subject: RE: I/O contention with external process reading the oracle logs (online redo logs) NB_ RESENDING in plain text - sorry, Outlook keeps seinding in html no matter what default i set! Hi lists, I am using Quest Shareplex product for Oracle to Oracle one way replication. I have two systems (source and target) and two environments (dev, demo). On system one, the environments are setup as schemas within one oracle instance (therefore each schema will be a SOURCE in the replication). My other system has each environment set up a separate Orace Instances (therefore each instance will become a TARGET in the replication). I am trying to configure 2 separate replication streams (ie so that each replication process is SEPARATE from the other - one for DEV and one for DEMO). I will accomplish this by setting up Shareplex to use mulitple processes. HOWEVER, Quest technical support has told me that this will cause contention. However, I dont see why is would from an os/oracle point of view. Basically Shareplex has a process which reads the online redo logs. tech support is suggesting that is there a two processes trying to access the same block in the logs that contention can occur. This does not make sense to me. Below is the blurb from techincal support when I questioned their initial repsonse: * The reason you might run into a contention is because multiple captue processes may be reading the same data block in the redo log. Since there is only one process that can access a single block, the other process may have to wait. Contention is a possibilty, and you will need to run some bench marks to find out how much, if any, contention you will have. * I would find it HARD to believe that only ONE process can read a block at a time. If this were true, then OLTP system would FAIL miserably! Anyone have any ideas/comments regarding the OS and Oracle interaction I mean are not the logs at this pointa UNIX file? and can't multiple processes read a single unix file without bringing the whole system to its knees? Also, I am NOT knocking the techincal support, but I believe that the opinion was formulated on an incorrect assumption on the operating system and Oracle. Thoughts/comments? Thanks in advance. Hannah -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
