This is the third and final QA blog post for the Seminars we did in the last week of April 2020. Thank you for your attendance. I will publish the replay recordings as soon as they are available and link them as well. For now, please find here 3 Live Seminars: Multitenant Seminar 3 Questions answered.
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Your Questions, our Answers for Seminar 3: Multitenant
| 103 | We are in the process of migrating to Oracle Cloud using the xtts method for cross platform migration and we seem to be encountering an issue with it expecting both the temp tablespace and the undo tablespace to be in the PDB during the import process. Is this how it works? We’ve had two failed runs when attempting to use the temp and undo from the CDB. A: Please, this is something you need to check with Oracle Support. This is nothing I can handle in a seminar or via the blog. |
| 104 | Autoupgrade is avaible on 12.2 and later? A: It works _TO_ 12.2.0.1 and 18c as long as you have at least the Jan 2019 RU applied, and of course to every version of 19c. |
| 105 | Wondering if the autoupgrade feature is available for windows? A: Of course it is!!! |
| 106 | Is autoupgrade available from version 12.2? A: It works _TO_ 12.2.0.1 and 18c as long as you have at least the Jan 2019 RU applied, and of course to every version of 19c. |
| 107 | 3 PDBs free – does this include pdb$seed? A: As I mentioned and the slide said, “USER CREATED” pdbs – so the PDB$SEED does not count. See here: https://mikedietrichde.com/2019/09/17/3-pdbs-included-with-oracle-19c-and-desupport-of-non-cdbs-with-20c/ |
| 108 | Mike – what are the common naming convention for CDB and PDB ? Anything interesting to share in your blog? A: There is no clear rule or guideline. Most customers actually use the same name as for the DB before. Once you are consolidated at 100%, it does not make much sense to prefix PDB… |
| 109 | In video see the 11.2.0.4 and 12.1.0 RDBMS autoupgrade to 19C but the document see: Applies to: Oracle Database – Enterprise Edition – Version 12.2.0.1 and later Oracle Database – Standard Edition – Version 12.2.0.1 and later A: This refers to the version you upgrade _TO_: 12.2.0.1 and later (for 12.2.0.1 and 18c with at least the Jan 2019 RU). As _FROM_, it must be 11.2.0.4 or later. |
| 110 | I was able to create 3 PDBs in my 19.3 SE. So is it really mandatory to have 19.5 to use this feature? A: If you could already, then all is fine. Customers reported to me that this was not possible as SE2 was available BEFORE we announced 3 PDBs. |
| 111 | So we can setup 3 pdbs in 19c without the need for multitenant license? A: Yes, see here: https://mikedietrichde.com/2019/09/17/3-pdbs-included-with-oracle-19c-and-desupport-of-non-cdbs-with-20c/ |
| 112 | We have 12.1 and 12.2.0.1 database with PDB’s. Is possible to plug the pdbs on 19c and then convert ? A: Yes, but I would ALWAYS upgrade at first. See: https://mikedietrichde.com/2019/07/22/database-migration-from-non-cdb-to-pdb-overview/ |
| 113 | IS RHEL 8 certification for Oracle Database 19 planned ? A. Yes, but I can’t give you a date. |
| 114 | Why non-CDB architecture is no longer supported in version 20? Why should I use CDB if I have only one database on the server? A: Well … this is a complicated topic I can’t answer on the blog |
| 115 | Is the clone of pdb’s all without downtime? A: For the source, yes |
| 116 | What about migration from db 12102 running on oracle linux 6 , into 19cdb running on oracle linux 7. Is there any restriction ? A: No – you do the preupgrade steps on source, then copy to destination and upgrade. |
| 117 | Can you please explain what should be changed from application point of view ? just to change the connection string? anything else that we should take into concideration while planning moving to CDB? A: Yes, things like monitoring, cron jobs, backup jobs |
| 118 | With the SE2 16 thread cap, will all PDBs be limited to sharing these 16 threads, or can they access 16 threads per PDB? A: I think it is across all PDBs, but please double check with Support. |
| 119 | Is there a way to disallow the sys user to connect to a pdb? A: No, all Oracle supplied users per se are common users. You can only go the other way round, and create common users by yourself with dedicated privs. If you need to prevent SYS seeing certain things, you will need to deploy DB Vault. |
| 120 | Hello, for upgrade 11.2.0.4 to 19c, if the receiving CDB must be precreated already, how do you precreate it on 11.2.0.4 since multitenant came since 12c? Thank you. A: You create it of course in 19c. Your 11.2.0.4 database will be upgraded to 19c, and then plugged into the CDB you precreated. |
| 121 | Is it possible to create multiple CDBs in same server? If yes, are there any license limits on the number of CDBs in single server with EE? A: The same license rules for PDBs apply as they are in place with EE depending on what your contract says. And of course you can have multiple CDBs on the same server. |
| 122 | I taught Mutimedia is deprecated? A: It is desupported in 19c – see: https://mikedietrichde.com/2019/02/18/oracle-multimedia-will-be-removed-in-oracle-database-19c/ |
| 123 | Why Apex must be installed on the PDB instead of the root? A: See here: https://mikedietrichde.com/2015/11/19/why-you-should-remove-apex-from-the-cdbroot/ |
| 124 | I have an 11.2.0.4 SE database with Oracle Locator. If I move it to 19c SE PDB, can I use spatial features without additional licensing? A: Yes, you can – see: https://mikedietrichde.com/2019/12/06/great-license-news-spatial-and-graph-machine-learning/ |
| 125 | As mentioned in the presentation, if the Spatial feature is enabled only at the container level, is it possible for the tenants (PDBs) to use this feature from the CDB itself? A: You have to have the SPATIAL component in the PDB then as well – simple install. But it must exist in the CDB$ROOT at first. |
| 126 | My question was about Local Undo tablespace characteristics. A: ?? |
| 127 | Sorry can you repeat “filename convert” — how to avoid typing the whole path? A: Instead of “CREATE PLUGGABLE DATABASE PDB1 … FILE_NAME_CONVERT(‘/u02/oradata/CDB1/pdbseed’,’/u02/oradata/CDB1/pdb1′)” you can also use “CREATE PLUGGABLE DATABASE PDB1 … FILE_NAME_CONVERT(‘pdbseed’,’pdb1′)” – this is shorter and works as well. |
| 128 | During remote cloning of pdb, will it cause slowdown at the source side? A: Not that I’m aware of. |
| 129 | Hot cloning only in EE ? A: No, this should work in SE2 as well. |
| 130 | Can you have 2 CDBs on a server using the same server resources? A: Yes, you can. |
| 131 | You have mentioned several features that were previously part of licensed options and are now free to use completely or limited use. I mean things like STS, the use max of three PDB’s , etc. My question is, were can I get a summary of that information by release? A: This is a tough question. I would say “On my blog” – but the best sources are (a) the Oracle License Guide and (b) the Oracle New Features Guide for each release. |
| 132 | Why is the conventional way of database creations being deprecated? A: Well, this is a longer story … |
| 133 | If you shutdown the cdb, will it automatically shutdown the pdbs normally? A: Yes, it does – and if you ABORT, it will stop all PDBs the same way. |
| 134 | May i see the status (open/shutdown/restricted etc.) of my pdb’s in GI with crsstat res -t? A: Yes, you will |
| 135 | How will the unplug + plug + upgrade work in a data guard configuration? As per 1576755.1 this seems transparent and standbys will also get converted. But I’ve also read this works only when active data guard is used. A: I hope I demonstrated this at the end of the talk as “Real World Example” |
| 136 | Does flashback PDB supported in 12.1 ? A: No – it requires Local Undo, a 12.2. feature |
| 137 | non_cdb_to_pdb is rerunnable starting with 12.2. Does it mean, not rerunable if database is 12.1? A: Exactly – you hit an unrecoverable error? Start again please by restoring your backup … |
| 138 | I miss near zero downtime migration. From 11.2 to 12.2 we used transient logical standby databases. Oracle forces customers to change to CDB as of version 20. Will Oracle deliver near zero downtime migration like transient logical? note that GG is very expensive A: Well, as of now I can recommend you OGG – and as I said, every move from non-CDB to PDB requires downtime. Please raise this to your Oracle contacts if you have concerns. I described the actual situation. And I fully understand your concern. |
| 139 | Any special instructions for RMAN backups for PDB’s ? A: Not from 12.2 on anymore – but in 12.1 there were some pitfalls. |
| 140 | Do you have an example with more detail on this part? A: No, I have no examples for RMAN – but the documentation (Multitenant and Backup/Recovery Guide should have some) |
| 141 | How does that work with TDE ? A: You need to copy your wallets |
| 142 | Can we use RMAN incremental backup to apply from non-cdb to PDB? A: No – the CDB is a different database, your archives don’t work there. |
| 143 | We are planning to upgrade from 11.2.0.4 to 19c, please refer to any use cases or any poc doc. Thanks A: What do you mean? Please browse my blog – you will find plenty of examples. And the hands-on lab covers this, too. |
| 144 | For client upgrading to oracle 19c and consolidating their dB in huge cdb to save license costs with optimised usage of resources(cpu etc) in cdb . But to use multitenancy in a big way , one needs to purchase separate multitenancy license which again is additional cost . How will we show cost saving then while upgrading to 19c n doing consolidation using multitenancy?? A: You can have 3 PDBs per CDB without MT license – so you are not forced to purchase it. If you would like to have an overall calculation about CAPEX and OPEX, I know that presales people have a calculator assisting you. |
| 145 | It was one of the best semiars I have had during my career. Thank you very much for your work. A: Thanks a lot – I appreciate your feedback 🙂 🙂 🙂 |
| 146 | When upgrading from 12.1 or 12.2.0.1 to 19c – would you recommend to go for PDBs in general or wait for 2Xc to make the step to PDBs? Our intention is to stick to the long term support release 19c for a while and then probably step again to the next long term support release 3 yrs later. A: Well, this is hard to answer. I think, the CDB architecture has some benefits as soon as you have more than 1 PDB. And it is always good to start earlier to adopt change than later and be under pressure. |
| 147 | Excuse me, I received no answer for the question I asked previously : for migration, how to precreate CDB on 11.2.0.4 (how if multinenant came with 12c) as you said it needed to be precreated. Thank you. A: You create it of course in 19c. Your 11.2.0.4 database will be upgraded to 19c, and then plugged into the CDB you precreated. |
| 148 | Our current state as in 12c, we have single DB per VM, what happen when we migrate to 19c? A: Nothing will change – you can have non-CDBs with 19c as well. The change will have to happen AFTER 19c. |
| 149 | How can one get a recommended oracle migration book? A: I can recommend this one: https://mikedietrichde.com/2017/12/19/book-recommendation-oracle-database-upgrade-migration-methods/ – there’s a newer edition available |
| 150 | 1. Is it possible to have more than one CDB on same server, same version? 2. Imagine we first migrate (not upgrade) via Datapump from 12.2 to non-cdb 19.7 on different servers. Once new non-cdb 19.7 is in production, to convert to CDB, with downtime, only steps are to create new CDB, create pdb.xml on source non-cdb 19c database, and then run script to convert or is it more complicated? Thanks A: 1. Yes, of course — 2. Yes, this is the way. But you could of course migrate directly into a PDB in 19.7 and avoid the noncdb_to_pdb.sql step |
| 151 | You have mentioned that dg broker must be disabled when upgarding. There’s a blog post written in 2017 I believe. But with the dbms_rolling Oracle doc states “As of Oracle Database 12c Release 2 (12.2.0.1), Data Guard broker can remain on during a DBMS_ROLLING rolling upgrade; there is no longer any need to disable it. ” A: DBMS_ROLLING is Active Data Guard, and builds Transient Logical Standby. There the Broker can be on whereas for a regular Transient Logical Standby you need to disable the Broker. For the upgrade itself, I’m a bit curious now … |
| 152 | Mike and Laura thanks a lot for the 3 very usefull seminars A: You are most welcome! |
| 153 | Is there change to your recommendation with regard to disabling broker A: No, there isn’t – but AutoUpgrade will handle this soon as well. See: https://mikedietrichde.com/2017/09/12/upgrade-disable-data-guard-broker/ |
| 154 | We are currently on 12.2.0.1 and use the duplicate command to clone our database to a reporting or test instance from an rman backup. How would we go about replicating this using the new 18c/19c version? A: At first, the same technique will work with 18c/19c as well of course. If your question is whether how this would change with Multitenant, then you’d do REFRESHABLE CLONES instead. Much easier, and less traffic. |
| 155 | There was some explanation on to how we can use dataguard to keep the standby database up-to-date during the migration. I am assuming the same applies to a physical standby? We will need to install the standby container and pdb separately before shipping logs over to keep instances in sync from production. How will the switch-over or fail-over to the standby work in this instance? A: I’m not 100% sure where the question is going to. You can do a rolling upgrade with a Transient Logical Standby (see: https://mikedietrichde.com/2018/05/09/transient-logical-standby-rolling-upgrades-overview/). And the same concept works with PDBs as well, but for the entire CDB with all its PDBs. This allows you to decrease the downtime to a few minutes typically. Please see the link – I think it explains how it works. |
Thanks again for your participation – and hopefully we’ll see each other in person again soon!
Further Information and Links
- Questions and Answers seminar 1 – Release Strategy, Patching and Cool Features for DBAs
- Questions and Answers seminar 2 – AutoUpgrade and Performance Stability
- Slides Download for all 3 Seminars
. - Database Migration from non-CDB to PDB – Overview
- Upgrade, plug in, convert (noncdb_to_pdb.sql) – 11.2.0.4 and higher
- Plugin, upgrade, convert (noncdb_to_pdb.sql) – 12.2.0.1 and higher
- Clone via NON$CDB, upgrade, convert – 12.1.0.2 and higher
- Typical Plugin Issues and Workarounds
- The Compatible Pitfall
- The Time Zone Pitfall
- The Component Pitfall
- The Patch Level Pitfall
- Various Pitfalls
- The Fallback Challenge
- The Minimal Downtime Challenge
–Mike
