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H2 compact database

H2 compact database

H2 Database: A relational database management system written in Java. It is a relational database management system written in Java. It can be embedded in Java applications or run in client-server mode; SQLite: A software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. SQLite reads and writes directly to ordinary disk files. A complete SQL database with multiple tables, indices, triggers, and views, is contained in a single disk file.

SQLite is a tricky beast. It's great if you're working single-threaded, but a Terrible Idea if you've got more than one concurrent connection. You use it because it's easy to setup, light, and portable it's just a file. For users wanting to scale Paperless up to a multi-user environment though, we do provide the hooks to switch to PostgreSQL.

Used during the "build process" of Coolfront Mobile's Flat rate search engine database. RDBTools is a self-hosted application, and it is important that the installation process is simple. With SQLite, we create a new database file for every analysis.

Once the analysis is done, the SQLite file can be thrown away easily. There's really no call for something heavier for this site.

How to perform offline defragmentation of the Active Directory database

SQLite is simple, easy to use and quite reliable given its age. H2 Database 49 Stacks. SQLite 5. Need advice about which tool to choose? Ask the StackShare community! H2 Database. What is H2 Database?

It can be embedded in Java applications or run in client-server mode. What is SQLite? Why do developers choose H2 Database?H2 Database. Search everywhere only in this topic. Advanced Search. Classic List Threaded. Auto-Compacting while Server is Running. Hi H2 Team! Like the previous poster, our db is growing and we need My question is, Now that the new format seems to be in place: Are there plans to implement that feature? If so, any idea when you would release it?

Is that feature being worked on now? Thanks, -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To post to this group, send email to [hidden email]. To unsubscribe from this group, send email to [hidden email]. Thomas Mueller Graf.

h2 compact database

Re: Auto-Compacting while Server is Running. Hi, Currently the database file only shrinks when closing the database shrinks for up to 2 seconds by default, and fully shrinks when running "shutdown compact". However empty space is automatically re-used even without closing the database that's different from versions 1.

It's possible to implement "shrink while running", however so far I didn't consider this very urgent. There is already a feature request: "Automatically compact databases from time to time as a background process.

Could you explain what is your use case? Good news. We're finally upgrading to 1.

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This may help our use case - see below. If you're talking about making a specific call to compact, then I don't think we're looking for that. We could implement a periodic call to do this if you didn't have the auto-compact.

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Our use case involves running an H2 server server mode which presently grows to over 20G. Hourly, we run a query to delete entries in the tables which are older than 14 days. Since space associated with those deletes is presumably empty. Now that we've upgraded from 1. This is probably not that urgent - I'm hoping that the upgrade will do a lot to help us with the space issue, since we were using a version that didn't automatically reuse empty space. I'll keep an ear open for any announcements about compacting and probably upgrade again when that happens.

Glenn -- You received this message because you are subscribed to the Google Groups "H2 Database" group. I want to make sure there is no misunderstanding: Currently the database file shrinks automatically when the database is closed. To be able to shrink, data from the end of the file is moved to the free space. This reorganization is running for up to one second, that means it may not shrink fully. To shrink it fully, run "shutdown compact". Currently empty space in the database file is re-used at runtime.

If you delete a lot of data, and then add a lot of data, the empty space is re-used. The database file only grows if there is no more empty space. What you ask is to automatically shrink the database file without closing the database.Skip to main content. Select Product Version. All Products. Active Directory automatically performs online defragmentation of the database at certain intervals as part of the Garbage Collection process.

By default, this occurs every 12 hours. Online defragmentation does not reduce the size of the database file Ntds. Performing an offline defragmentation creates a new version of the database file without internal fragmentation. It also re-creates all indexes. Depending on how fragmented the original database file was, the new file may be much smaller. More Information. Windows Server Backup natively supports backing up Active Directory while online.

This occurs automatically when you select the option to back up everything on the computer in the Backup Wizard, or independently by selecting to back up the "System State" in the wizard. Start "msconfig," and go to the boot pane. Select the OS installation that you want to configure. After you click OKthe tool asks you to restart. Restart the computer. Log on to the administrator account by using the password that is defined for the local administrator account in the Directory Service Restore Mode SAM.

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Yes No. Tell us what we can do to improve the article Submit. Your feedback will help us improve the support experience. Australia - English. Bosna i Hercegovina - Hrvatski.Restarting the Runtime has no or very small effect on the file's size. See the Designer's Help to know how to configure the Runtime with an external log database. When deleting data from the H2 database, the file is not reorganized in real time: this requires a database shutdown. When shutting down, H2 "compacts" the file in order to reduce the file size.

But this operation is limited to milliseconds duration default H2 behaviour. Here is how to do:. Suggest a new Article! Remember Me.

h2 compact database

You can easily find in which Process or Mapping a Metadata is used. Here is how to do: Stop all the Runtimes which use this database Open a command line and change directory cd to the Runtime's directory.

Knowledge Base. Too many nested apply-templates calls. Exception thrown by OutputURIResolver" when preparing a process Error "input file does not exist" when building mapping after changing folder's or file's case Error "no security manager: RMI class loader disabled" when connecting to a Runtime Cannot open a workspace User interface looks tiny on high resolution screens Runtime Issues Runtime does not start - no visible error Runtime startup and execution time is slow on MAC OS Runtime will not start with error "java.

ServiceException: Bad Gateway" Error "java. NumberFormatException: For input string Cannot load JDBC driver NoSuchMethodError: io. Email Password Remember Me Forgot your password? Forgot your username? Create an account.Copies and compacts a closed database, and gives you the option of changing its version, collating order, and encryption. Microsoft Access workspaces only. Also, linked tables have a character limit for the encryption key.

See the Encrypted linked tables section at the end of this topic. Identifies an existing, closed database. If the file name has an extension, you must specify it. You can also specify a network path. You can't use this argument to specify the same database file as SrcName.

A string expression that specifies a collating order for creating DstName, as specified in Remarks. A constant or combination of constants that indicates one or more options, as specified in Remarks. You can combine options by summing the corresponding constants.

A string expression containing an encryption key, if the database is encrypted. If you include a password setting in DstLocale, this setting is ignored. NOTE : This is deprecated parameter and is not supported in. ACCDB format. To encrypt an. Use strong passwords that combine upper- and lowercase letters, numbers, and symbols. Weak passwords don't mix these elements. Strong password: Y6dh!

Weak password: House Use a strong password that you can remember so that you don't have to write it down. You can use one of the following constants for the DstLocale argument to specify the CollatingOrder property for string comparisons of text. You can use one of the following constants in the options argument to specify whether to encrypt or to decrypt the database while it's compacted.

If you omit an encryption constant or if you include both dbDecrypt and dbEncryptDstName will have the same encryption as SrcName. You can use one of the following constants in the options argument to specify the version of the data format for the compacted database. This constant affects only the version of the data format of DstName and doesn't affect the version of any Microsoft Access-defined objects, such as forms and reports.

Creates a database that uses the Microsoft Jet database engine version 1. Creates a database that uses the Microsoft Jet database engine version 2. Creates a database that uses the Microsoft Jet database engine version 3. Creates a database that uses the Microsoft Jet database engine version 4. Creates a database that uses the Microsoft Access database engine version You can specify only one version constant.

If you omit a version constant, DstName will have the same version as SrcName. You can compact DstName only to a version that is the same or later than that of SrcName. As you change data in a database, the database file can become fragmented and use more disk space than is necessary.

Periodically, you can use the CompactDatabase method to compact your database to defragment the database file. The compacted database is usually smaller and often runs faster.

You can also change the collating order, the encryption, or the version of the data format while you copy and compact the database.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

According to h2 db documentation. When closing the database, the database is automatically compacted for up to milliseconds by default. Empty space is created every time a row is deleted or updated. Unfortunately at runtime the database file is growing continuously. In this discussion it is suggested to backup the database, and restore it again.

Is there a way do achieve this? Of course it is an option to migrate to a database like Postgres. However my project should be very easy to install, so it would be necessary to integrate it into the installer.

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In general adding a dedicated database adds some overhead. Learn more. Ask Question.

h2 compact database

Asked 8 years, 6 months ago. Active 8 years, 6 months ago. Viewed 5k times. Heading In one of my projects I am using h2 database with file storage. According to h2 db documentation "Empty space in the database file [is] re-used automatically. Marius Jeskulke Marius Jeskulke 4 4 silver badges 9 9 bronze badges.

Do you know why the database file is growing continuously? Unless you always add more data than you delete, this shouldn't be the case. Hi Thomas. Thanks for your question! The problem is in fact adding and updating. H2db appends to the end of the file, but the "deleted" space within the file is not reused.

That's strage. Do you have a short, self contained, compilable, example sscce. I'll provide exactly that in about 10 days. I am leaving Europe for some days this evening, so unfortunately I cannot provide it earlier.

I didn't analyze the test program yet, but the upper limit is most likely the transaction log size. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.H2 Database. Search everywhere only in this topic. Advanced Search. Classic List Threaded. Automatically compact databases from time to time as a background process. Hi, I use H2 in a commercial product and I have an issue regarding the size of the DB with a customer.

This is not acceptable from customer comment.

DBEngine.CompactDatabase method (DAO)

NOTE: current version used of h2 are 1. Do you have another solution to avoid this issue long startup and compact at runtime? Best regards. To post to this group, send email to [hidden email]. To unsubscribe from this group, send email to [hidden email]. Noel Grandin. Re: Automatically compact databases from time to time as a background process. Not sure what Thomas' plans are, but what I can suggest is that you set this setting to a nice large number -Dh2.

Thanks for the quick answer but currently it's not possible to reboot my application on a regular basis because my application must ensure scheduling, failover, HA I really need to have a solution at runtime without restarting my application. If you want to look at it yourself, the relevant code is in org. In reply to this post by IntensiveH2.

Hi I had a quick bash at implementing this by taking an exclusive lock on the DB and re-using the existing compacting code. But the unit test I added indicates that I'm corrupting the database somehow. Patch attached - Thomas, perhaps you have an idea? Regards, Noel. Hi Thanks for your patch but customer is on production and I must to have a robust solution. Could you send me a jar file instead of a patch file It's more easy and especially faster for me to validate it.

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When do you have a reliable solution related to your previous comment "that I'm corrupting the database somehow"? Thanks Thierry. Wolfgang Pedot. In reply to this post by Noel Grandin.