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Questions tagged [mapdb]

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap memory

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap memory. It is a fast and easy to use embedded Java database engine. And it is completely free under Apache License. MapDB is free as speech and free as beer under Apache License 2.0.

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Map Db compact method usage and how can it used to clear memory

Can anyone tell me what is the usage of mapdb.compact() method.I am looking for how to clear the objects from heap after calling commit() method
Shig
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what is the cost of using `checksumHeaderBypass` in mapdb?

we are using mapdb to store a list of files that have been visited during a long running process, so that if we need to abort or if the process crashes we can resume where we left off. we want to protect against crashes corrupting our mapdb file…
Nicholas DiPiazza
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How to relate objects with MapDB

I'm working, for school purpose, to a java web application based on GWT and MapDB for data persistency. Since I'm not really familiar with MapDB I need some help. My application has to manage an online system for selling and buying through an…
JamieITGirl
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References and "foreign keys" with MapDB

Having worked only with MySql so far, I can't understand how to manage in MapDB what in MySql I do with foreign keys. For example, if I have two (or more) ConcurrentNavigableMap with some data (like objects), how can I relate the data between these…
JamieITGirl
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Http error 500 with GWT web application

I've read tons of materials but I can't figure out what's happening. I'm doing a simple web application with Eclipse Oxygen, GWT 2.8, MapDB3, when I try to launch the web app through Run as --> GWT development mode with Jetty I obtain the error…
JamieITGirl
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ConcurrentNavigableMap with MapDB 3.0.5

I'm using the latest version of mapDB (3.0.5) and I have this set of instructions: DB db = DBMaker.fileDB(new File(FILE_NAME)).closeOnJvmShutdown().make(); ConcurrentNavigableMap utente = db.getTreeMap("utente"); if…
JamieITGirl
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MapD slow on text fields

In benchmarking the following query: SELECT * from test order by c0 asc limit 1 Out of ten tests we get: Took: 7877 ms. (7.877 s) Took: 15617 ms. (15.617 s) Took: 8067 ms. (8.067 s) Took: 15924 ms. (15.924 s) Took: 8057 ms. (8.057 s) Took: 15864…
David542
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org.mapdb and maven2 trouble

I'm new to Maven. I'm trying to add a reference to org.mapdb in my java/maven2 pom.xml file, but maven seems unable to download mapdb artifact from remote repository. What I've done: First thing: configured remote maven repository in…
jazzter
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MapDB, serializers and compression

I'm researching into off-heap cache and can't seem to find much information/benchmarks on memory consumption on-heap vs. off-heap (still in memory). I'm planning to use MapDB. Documentation indicates that compression can be applied on serialized…
MeIr
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Ordered persistent cache

I need a persistent cache that holds up to several million 6 character base36 strings and has the following behavior: - When clients retrieve N strings from the cache, they are retrieved in the order of the base36 value e.g. AAAAAA then AAAAAB…
sam
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MapDB in-memory with disk fallback

I'm working on an Hadoop project. My reduce phase is very memory expensive. I'm currently using an HashMap, but I get the Error: Java Heap space because in Reduce I build a huge hashmap (the dataset is 32GB). The solution could be an in-memory…
alfredopacino
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GWT - RPC serialization exception and MapDB

I'm using gwt and I'm using mapdb and when I retrieve data as a map (BTreeMap) gwt throw rpc serialization exception. I wrapped the map in an object that implements Serializable and IsSerializable but that don't work. I don't know why this doesn't…
Peduz
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How include MapDB in a GWT project

I'm using this Guide for adding MapDb to my project. i'm trying to make a simple user registration but i don't understand where and how i can put the lib inside my project! Where include this code org.mapdb …
Dario
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How to create HTreeMap with case insensitive key?

I have created HTreeMap with the following syntax but how should I specify case insensitive on the key. if there is a entry in the map with the key TOMAS, the method contains should return true when checked with string tomas. HTreeMap
Hari
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NPE while autoboxing in Java

I have the following piece of code: map = db_.treeMapCreate(validMapName_) .keySerializer(Serializer.LONG) .valueSerializer(Serializer.LONG) .make(); //mapDB protected void onTaskCompletion(TaskInfo task) { long…
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