I backed up a neo4j database using
bin/neo4j-admin dump --database=neo4j --to=c:/
Then I load a database from an archive created with the dump command as follow
bin/neo4j-admin load --from=/var/lib/neo4j/data/c: --database=db
From Neo4j Enterprise Browser I execute
SHOW DATABASES
but I don't see the db previously loaded. How could I show it ?
If you are replacing your existing database with name "db" then use the --force option:
bin/neo4j-admin load --from=/var/lib/neo4j/data/c: --database=dbase --force
If you are restoring into a new database, then after the load, you need to create the database CREATE DATABASE dbase
Note that I changed the name of your database from db to something else since database names in Neo4j must be at least 3 characters long.
Our Developers is working in Local Standalone Solr Server and we have many cores in Local Solr. Now we are planning to migrate it to SolrCloud in AWS Infrastructure for replication purpose with numShards:3 and replicationFact:3. We don't need data to be migrated from Local Solr server to AWS SolrCloud. We only need to transfer Core from Local Solr to collection in SolrCloud. I am newbie in these can you please any help me in these.
1) In layman word we only need to transfer content in Conf folder of core to SolrCloud Collection and we don't need to transfer data(data folder).
Answering the my own question ,so any one can check it, if issue arise.
Solution:
1) Create a new collection in SolrCloud with config set name same as of core.
2) Move the conf folder of the core in Local Standalone Solr Server to SolrCloud 'Collection' Folder.
3) Run zookeeper's zkCli.sh commands from bash to upload the conf file to all SolrCloud server.
cd /opt/solr/server/scripts/cloud-scripts/
bash zkcli.sh -cmd upconfig -confdir /opt/solr-7.4.0/server/solr/collectionname/conf/ -z IP1:2181,IP2:2181,IP3:2181 -confname confname
Reference : https://lucene.apache.org/solr/guide/6_6/using-zookeeper-to-manage-configuration-files.html#UsingZooKeepertoManageConfigurationFiles-UploadingConfigurationFilesusingbin_solrorSolrJ
If I was to accidentally run a UserModel.remove({}, cb) and delete all of my user documents, how would I retrieve those documents? Would the process be same on a local DB on my computer VS a DB hosted on a remote server such as mLab?
No they can not be retrieved back once deleted. The only way to recover the data is to create a dump of that collections before deleting it or if you have a replica of that server. You can restore it from that.
I want to be able to run a SOLR instance on my local computer by have the index directory on a remote server. Is this possible ?
I've been trying to look for a solution for days. Please help.
Update: We've got a business legal requirement where we are not allowed store client data on our servers ... we can just read, insert, delete and update it on Client request via our website and the data has to be stored on client servers. So each client will have their own index and we cannot run SOLR or any other web application on Client's server. Some of the clients have dropbox business account. So we thought may be just having the SOLR index file upload to dropbox might work.
enable remote streaming in solrConfig.xml and configure the remote file location in it.
It's working
We can delete all nodes and relationships by following query.
MATCH (n) OPTIONAL MATCH (n)-[r]-() DELETE n,r
But newly created node get internal id as ({last node internal id} + 1) . It doesn't reset to zero.
How can we reset neo4j database such as newly created node will get id as 0?
From 2.3, we can delete all nodes with relationships,
MATCH (n)
DETACH DELETE n
Shut down your Neo4j server, do a rm -rf data/graph.db and start up the server again. This procedure completely wipes your data, so handle with care.
run both commands.
match (a) -[r] -> () delete a, r
above command will delete all nodes with relationships.
then run ,
match (a) delete a
and it will delete nodes that have no relationships.
Dealing with multiple databases.
According to Neo4j manage multiple databases documentation:
One final administrative difference is how to completely clean out one database without impacting the entire instance with multiple databases. When dealing with a single instance and single database approach, users can delete the entire instance and start fresh. However, with multiple databases, we cannot do that unless we are comfortable losing everything from our other databases in that instance.
The approach is similar to other DBMSs where we can drop and recreate the database, but retain everything else. Cypher’s command for this is CREATE OR REPLACE DATABASE <name>. This will create the database (if it does not already exist) or replace an existing database with a clean one.
When neo4j is initiated, it is possible to access two databases, a system database and a default (neo4j) database. To clear/reset neo4j database:
1 - Switch to system database:
:use system
2 - Show all databases created with the instance:
SHOW DATABASES
3 - Run the command to clear the database.
CREATE OR REPLACE DATABASE <name>
In my experience, there are two ways to reset a Neo4j database, depending on what you need.
Method 1: Simply delete all nodes/relationships/indexes/constraints
In Neo4j Browser, or in Py2neo with graph.run() (link).
# All nodes and relationships.
MATCH (n) DETACH DELETE n
# All indexes and constraints.
CALL apoc.schema.assert({},{},true) YIELD label, key RETURN *
However, despite being convenient, this approach is not suitable in case of using command neo4j-admin.bat import for BULK import, i.e. ideal for importing millions of nodes at once quickly.
Method 2: Reset database for BULK Import Tool
It's not possible to BULK import when the database is not empty. I tried the above method, but still received the error:
Import error: C:\Users\[username]\AppData\Local\Neo4j\Relate\Data\dbmss\dbms-dd16c384-78c5-4c21-94f3-b0e63e6c4e06\data\databases\neo4j already contains data, cannot do import here
Caused by:C:\Users\[username]\AppData\Local\Neo4j\Relate\Data\dbmss\dbms-dd16c384-78c5-4c21-94f3-b0e63e6c4e06\data\databases\neo4j already contains data, cannot do import here
java.lang.IllegalStateException: C:\Users\[username]\AppData\Local\Neo4j\Relate\Data\dbmss\dbms-dd16c384-78c5-4c21-94f3-b0e63e6c4e06\data\databases\neo4j already contains data, cannot do import here
To tackle this issue, I deleted the following folders:
c:\Users\[username]\AppData\Local\Neo4j\Relate\Data\dbmss\dbms-dd16c384-78c5-4c21-94f3-b0e63e6c4e06\data\databases\neo4j
and
c:\Users\[username]\AppData\Local\Neo4j\Relate\Data\dbmss\dbms-dd16c384-78c5-4c21-94f3-b0e63e6c4e06\data\transactions\neo4j
Then carried out the Import command:
"C:\Users\[username]\AppData\Local\Neo4j\Relate\Data\dbmss\dbms-dd16c384-78c5-4c21-94f3-b0e63e6c4e06\bin\neo4j-admin.bat" import --database=neo4j --multiline-fields=true --nodes=node_ABC.csv --nodes=node_XYZ.csv relationships=relationship_LMN.csv --relationships=relationship_UIO.csv
Start the Neo4j database. In Neo4j Desktop, the labels and relationships should now be recognized.
Notice that the database I deleted (neo4j) and the database I imported to are the same.
This worked for me with ver. 4.3.2 of the community editition:
Stop the server
cd <neo home>
rm -Rf data/databases/* data/transactions/*
Restart the server
Now you've again the system and the neo4j DBs. The command above deletes the system DB too, and that seems necessary, since deleting a regular DB only (which, in the community edition can only be 'neo4j') makes the metadata in the system DB inconsistent and you start seeing errors.
data/dbms seems to contain the user credentials and you can keep it if you want to keep existing users (else, you'll go back to the default neo4j/test user).
The recommended method is to use the DROP or CREATE Cypher commands, however, these are available in the enterprise edition only (I think it's a shame that a basic feature like this is part of their premium offer, but that's it).
This command deletes everything but requires apoc to be installed :
CALL apoc.periodic.iterate('MATCH (n) RETURN n', 'DETACH DELETE n', {batchSize:1000})
If you are using it on a docker container, you can do
docker-compose rm -f -s -v myNeo4jService
Since neo4j only runs current database specified in the conf file, an easy way to start a new and clean db is to change the current database in the neo4j.conf file and then restart neo4j server.
dbms.active_database=graph.db --> dbms.active_database=graph2.db
Some might argue that the database name is changed. But as of this writing [2018-12], neo4j doesn't support multiple database instances. There is no need for us to differentiate between databases, thus the name of the database is not used in our code.
You can clear/truncate the database with the command below:
MATCH (n) DETACH DELETE n
What this command does is, it matches all the nodes in the database, then detaches all the relationships the matched nodes have and finally deleting the nodes themselves.