Oracle released a patch to fix the scn growth rate bug in hot backup listed as 12371955. The patches provide the safety measure to ensure that you dont have any issue with database links independent of any possible future change in your transaction rate. From the article weve learnt this new feature is scn compatibility, which has a time limit set in it and requires this patch to be applied. This infoworld article from jan 17, 2012 fundamental oracle flaw revealed did alert oracle database customers. Copyright 2019 oracle andor its affiliates all rights reserved. In 11g theres a patched bug that caused the scn to increase drastically when an online backup is done, and causes it to continue increasing drastically. Infoworld has raised this issue to oracle before going public with it. For almost all oracle databases, this headroom is constantly increasing every second. Computer world has an comprehensive article about this issue. On this session you will refer to methods on how to identify the list of oracle patches sbp, dbbp or bundle patches that are installed from r3 level and os level methods from os level. Moreover, what about oracle 10g r2 and older, those editions are not supported anymore so no additional patches will be released. This security vulnerability specifically relates to the oracle system change number scn and ways to increase the scn beyond the current maximum value scn headroom or maximum reasonable scn in order to stop processing. The newer or patched databases will have higher scn rate or higher current max scn limit. Oracle data pump is a mature, full featured and flexible tool for oracle database migration.
Following metalink notes provides means to test if the database is affected by this bug. Personally i think this is a low risk bug but applying the patch to mitigate the risk is highly recommended for following. Investigating the scn intrinsic growth rate qualogy. Questions like am i affected or when should i apply the patch are common. Error ogg02912 patch 17030189 is required on your oracle mining database for trail format release 12. Using sql patch to add hints to a packaged application. This is a number that increments sequentially with every database commit. The fixuntil recently, aside from the backup bug fix, oracles only response to the scn elevation issue as far as weve been able to determine has been to release a patch that extends the. For many people working with oracle database, scn system change number is a topic that interests them greatly but despite that its a fascinating topic, its confusing as well. Besides reading oracle support documents i wanted to recreate a database link issue on a couple of test databases. A stamp that defines a committed version of a database at a point in time. Critical oracle database bug system change number scn.
A withdrawn patch in sun terminology is called an obsolete patch in oracle terminology. Different from normal reports or news for oracle users, oracle point the exact version 11. The system change number scn is a logical, internal timestamp used by the oracle database. Doing this ensures that oracle databases will ration scns over time, allowing over 500 years of data processing for any oracle database.
Critical oracle database bug system change number scn cve. Typically, when a bug results in a database outage, affected systems can simply be recovered from backups. Databases need to be patched to a minimum before april 2019. This security vulnerability specifically relates to the oracle system change number scn and ways to increase the scn beyond the current maximum value scn headroom or maximum reasonable scn in order to. Past few day, since oracle has lunched jan security patch there is amazing sort of hype in the market regading the issue revealed with oracle architecture.
Its good to use a latest bundle patch for latest correctionsbug fixes, but very bad that still you are on out dated version of oracle. Note that the naming convention and content of the sun patches have not changed. The patch fix resolves the hot backup bug and many other unknowns but you are still not fully protected from scn hacks or other unknown triggers. Oracle released a patch to fix the arbitrary scn growth rate bug in the hot backup code before infoworld began researching this story.
System change number scn at which you started the export. Status usage 10 new, not ready for development use to file a bug without all the needed information for instance, trace files from the customer, to inform development that a bug will soon become status 11. My oracle support provides customers with access to over a million knowledge articles and a vibrant support community of peers and oracle experts. This security vulnerability specifically relates to the oracle system change number scn and ways to increase the scn. So again, its strongly recommended to apply the jan 2012 psu or cpu if you are just asking for security fixes to your environments. If this patch is not applied, the unpatched database will have a lower scn rate or lower current max scn limit. Personally i think this is a low risk bug but applying the patch to mitigate the risk is highly recommended for following reasons. Offline patch and online patch within sbp sap on oracle. Ask tom restore using duplicate is failing oracle ask tom. This caused some confusion for oracle database users who thought that database links would not work anymore after april 2019 if no additional patch was installed. Oracle scn bug revealed cpu jan 2012 to address it.
If you have a packaged application, you might be wondering how you can use this hint. The database always has transactions going on, always. An obsolete patch using oracle terminology is a patch which is no longer available for download, for example, because it was defective. System change number scn, headroom, security and patch information doc id 76995. The newer or patched databases will have higher scn rate or higher. Database links and scns on june 23, 2019 bobby durretts. So what key f unction w as introduced in this patch and changed the algorithm of oracle scn. To fix these issues, you need to download the following oneoff patches for the platforms that you use. You should first read the following documents on oracle support to understand the problem. So it is recommended to run scn health check at regular intervals to prevent any runaway growth. I read about the scn bug a few years ago a wildly increasing value of the. Oracle community seems to be in some what confused state after infoworld published an article about oracle scn flaw. Oracle released a patch to fix the scn growth rate. June 23 2019, date of the scnbug amis, data driven blog.
At any point in time, the oracle database calculates a not to exceed limit for the number of scns a database can have used, based on the number of seconds elapsed since 1988. These patches increase the databases current maximum scn system change number limit. Future throughput in rolling out the patches in its january 2012 critical patch update, oracle revoked a patch described in fundamental oracle flaw revealed that increased the scn soft limit. Infoworld magazine today published detailed information regarding oracle database security bug cve20120082, which has associated fixes in the oracles january 2012 critical patch update. In this article we will learn the nittygritty of scn. Oracle assigns every committed transaction a unique scn. On february 15th 2018 oracle published note 2361478. The problem is that, due to a unknown reason, issuing the begin backup command causes the scn for the database instance to increase dramatically, so that the scn continues to increase at an accelerated rate even after the end backup command is given. There are patches available for this bug for several platforms.
Drop everything and patch your oracle databases datavail. It has negative connotations, like a cloth patch used to repair worn out clothing. All about headroom and mandatory patching before june 2019. These bug fixes will be available with the oneoff patch available on the oracle goldengate support site, mos. The scn is crucial to normal oracle database operation. I read about the scn bug a few years ago a wildly increasing value of the scn till a certain limit has been reached, and took this for granted most of it. The command to modify the database scn algorithm is. With 2012 january psucpu oracle has patched the scn growth bug, the case when a database is having a high rate change for scn. At the core of the issue is the system change number scn in oracle. Recommended patches and actions for oracle databases versions 12. Monin will oracle database links really stop working. The purpose of this page is to clarify how to identify oracle patches or bundle patches sbp in sap system.
Check the patch level required to avoid scn issues with database links. If you have not already done so, oracle recommends that you install this patch immediately. This is known as the databases current maximum scn limit. This patch impacts the system change number, or scn, that oracle calculates by looking at the number of seconds since 1988. The scn just marks a consistent point in time in the database. There are some recommended patches which are needed to be applied to the database to use the integrated capture extract in oracle goldengate. The massive implementations using rare combinations of features showed the flaw. This applies to oracle databases older than oracle 11. Fundamental oracle flaw revealed it world canada news. A checkpoint is the act of writing dirty modified blocks from the buffer cache to disk. Oracle offers a comprehensive and fully integrated stack of cloud applications and platform services. Oracle bug with available patch backup and recovery impacted. Oracle has released a patch titled high scn growth rate from alter database begin.
Oracle db bug ora12592,ora37,ora3106 on vmware esxi. Oracle bug status codes this document describes bug status codes and their usage. Oracle scn system change number is a mechanism to maintain data consistency in oracle database. Download patch 12991286 from the my oracle support website and follow the instructions in the readme file. High scn growth rate from alter database begin backup in 11g. However, youre not going to be able to wait on patching your oracle databases that are 12. Fundamental oracle flaw revealed a design decision made by oracle architects long ago may have painted some of oracles largest customers into a corner. Scott prefers the term update as its more positive, suggesting the provision of positive change, not just repairs i wholeheartedly agree with him as patches deliver positive change feature enhancements, performance enhancements, hardware support, etc. And another customer is in a large project of upgrading a 10. Plan and execute oracle upgrade from 10g to 11gr2 for latestnew features and for a sustainable support. Oracle scn bug revealed cpu jan 2012 to address it quest.
On this date, changes in the maximum scn limit will happen. Patches have arrived, but how much will they correct. Database links and scns on june 23, 2019 bobby durretts dba. This issue is tracked with oracle bug 18370031, which was logged for release 12. The difference between the current scn the database is using, and the current max scn, is known as the scn headroom. That plus the fact that whenever two oracle databases connect, they apparently sync scns, always going with the higher one, of course, seem to be the most concerning factors here. Monin will oracle database links really stop working after april.
1377 207 1101 1055 1211 958 854 1414 1150 306 45 1449 486 1075 1007 67 599 740 676 774 212 161 1281 784 1309 1352 802 115 1499 1172 1396 1145 1073 1185 328 1198 31 1212 405 979 944 718 1112 219 866 328