I have created a neo4j and graphql application with neo4j 4.0. In my application, I used two neo4j databases. These instances run in a docker container on my PC. But When I tried to run a query using graphql playground, graphql server gives the following error.
"Could not perform discovery. No routing servers available. Known routing table: RoutingTable[database=default database, expirationTime=0, currentTime=1592037819743, routers=[], readers=[], writers=[]]"
I created neo4j driver instance and session instance as following
const driver = neo4j.driver(
process.env.NEO4J_URI || "neo4j://localhost:7687",
neo4j.auth.basic(
process.env.NEO4J_USER,
process.env.NEO4J_PASSWORD
)
);
const session = driver.session(
{
database: 'mydb',
}
)
I couldn't find any way to fix this issue. Can someone help me to fix this? thank you.
If you use single server please use bolt:// as protocol. The it will not ask the server for routing tables
Related
I'm attempting to connect to a new Aurora PostgreSQL instance with Babelfish enabled.
NOTE: I am able to connect to the instance using the pg library through the normal port 5432 (the Postgres TDAS endpoint).
However, for this test, I am attempting to connect through the Babelfish TDS endpoint (1433) using the standard mssql package.
If I specify a database name (it is correct), I receive the error 'database "postgres" does not exist':
var config = {
server: 'xxx.us-east-1.rds.amazonaws.com',
database: 'postgres',
user: 'xxx',
password: 'xxx'
};
and the connection closes since the connection fails.
if I omit the database property in the config, like:
var config = {
server: 'xxx.us-east-1.rds.amazonaws.com',
user: 'xxx',
password: 'xxx'
};
It will connect. Also, I can use that connection to query basic things like SELECT CURRENT_TIMESTAMP and it works!
However, I can't access any tables.
If I run:
SELECT COUNT(1) FROM PERSON
I receive an error 'relation "person" does not exist'.
If I dot-notate it:
SELECT COUNT(1) FROM postgres.dbo."PERSON"
I receive an error "Cross DB query is not supported".
So, I can't connect to the specific database directly and if I connect without specifying a database, I can't cross-query to the table.
Any one done this yet?
Or, if not, any ideas on helping me figure out what to try next? I'm out of ideas.
Babelfish databases (that you connect to on port 1433) have nothing to do with PostgreSQL databases (port 5432). Essentially, all of Babelfish lives within a single PostgreSQL database (parameter babelfishpg_tsql.database_name).
You seem to have a single-db setup, because Cross DB query is not supported. With such a setup, you can only have a single database via port 1433 (apart from master and tempdb). You have to use CREATE DATABASE to create that single database (if it isn't already created; ask sys.databases).
I can't tell if it is supported to create a table in PostgreSQL (port 5432) and use it on port 1433 (the other way around is fine), but if so, you have to create it in a schema that you created with CREATE SCHEMA while connected on port 1433.
The answer was that I should be connecting to database "master".
Even though there is no database titled master in the instance, you still do connect to it.
Once connected, running the following:
select current_database();
This will indicate you are connected to database "babelfish_db".
I don't know how that works or why a database would have an undocumented alias.
The bigger answer here is that cross-DB object references are not currently supported in Babelfish, outside your current SQL Server database.
This is currently being worked on. Stay tuned.
I am using mongoose version 4.13.6 and mongodb from compose, and below is my code for connecting to mongo database.
mongoose.createConnection('mongodb://[user]:[pass]#[host1]:[port1],[host2]:[port2]/dbnamme?ssl=true', {});
But when I run this am getting error,
MongoError: no primary found in replicaset
Dont know why is that, can anyone help me in this?
So the short answer is this:
... all drivers are not equal and some make assumptions when multiple hosts are specified. For example, the Meteor/Node.js MongoDB driver sees two hosts and assumes it is talking to a replicaset. Upon connecting the driver asks which host is master and then errors out because neither of them are. The simple fix for this is to use one host in the URI ..
https://www.compose.com/articles/connecting-to-the-new-mongodb-at-compose/#drivingtoyourfirstdatabase
So when you create a connection, simply use one of the connection URIs for the database you want to connect to like:
var uri = "mongodb://<username>:<password>#[host]:[port]/<db_name>?ssl=true";
mongoose.createConnection(uri);
I'm building a webapp using the following the architecture:
a postgresql database (called DB),
a NodeJS service (called DBService) using Sequelize to manipulate the DB and Epilogue to expose a REST interface via Express,
a NodeJS service called Backend serving as a backend and using DBService threw REST calls
an AngularJS website called Frontend using Backend
Here are the version I'm using:
PostgreSQL 9.3
Sequelize 2.0.4
Epilogue 0.5.2
Express 4.13.3
My DB schema is quite complex containing 36 tables and some of them contains few hundreds of records. The DB is not meant to write data very often, but mostly to read them.
But recently I created a script in Backend to make a complete check up of datas contained inside the DB: basically this script retrieve all datas of all tables and do some basic checks on datas. Currently the script only does reading on database.
In order to achieve my script I had to remove the pagination limit of Epilogue by using the option pagination: false (see https://github.com/dchester/epilogue#pagination).
But now when I launch my script I randomly obtained that kind of error:
The request failed when trying to retrieve a uniquely associated objects with URL:http://localhost:3000/CallTypes/178/RendererThemes.
Code : -1
Message : Error: connect ECONNRESET 127.0.0.1:3000
The error randomly appears during the script execution: then it's not always this URL which is returned, and even not always the same tables or relations. The error message before code is a custom message returned by Backend.
The URL is a reference to the DBService but I don't see any error in it, even using logging: console.log in Sequelize and DEBUG=express:* to see what happens in Express.
I tried to put some setTimeout in my Backend script to slow it, without real change. I also tried to manipulate different values like PostgreSQL max_connections limit (I set the limit to 1000 connections), or Sequelize maxConcurrentQueries and pool values, but without success yet.
I did not find where I can customize the pool connection of Express, maybe it should do the trick.
I assume that the error comes from DBService, from the Express configuration or somewhere in the configuration of the DB (either in Sequelize/Epilogue or even in the postgreSQL server itself), but as I did not see any error in any log I'm not sure.
Any idea to help me solve it?
EDIT
After further investigation I may have found the answer which is very similar to How to avoid a NodeJS ECONNRESET error?
: I'm using my own object RestClient to do my http request and this object was built as a singleton with this method:
var NodeRestClient : any = require('node-rest-client').Client;
...
static getClient() {
if(RestClient.client == null) {
RestClient.client = new NodeRestClient();
}
return RestClient.client;
}
Then I was always using the same object to do all my requests and when the process was too fast, it created collisions... So I just removed the test if(RestClient.client == null) and for now it seems to work.
If there is a better way to manage that, by closing request or managing a pool feel free to contribute :)
I wrote a node web app and created a mongoDb database on my local system. I was using the following code to connect to local mongodb from node js
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/db_name'); //local
And everything was working fine on my local machine. So I went on and created an mlab account and created a database. But when I tried to run the code by changing the connection string, connections are still established I believe. But the find and save requests are not invoking the callbacks, even no errors shows up. All requests are getting timed out.
var mongoose = require('mongoose');
mongoose.connect("mongodb://user:pass#ds036789.mlab.com:36789/db_name"); //mlab
Another thing I noticed is that I cannot ping ds036789.mlab.com. But TCP connections are succeeding when I tried the nc command
nc -w 3 -v ds036789.mlab.com 36789
I even tried deploying to azure. Which doesn't work either. Any help is much appreciated. Thanks.
EDIT:
Not being able to ping was due to the fact that I used azure hosting. It is expected. And I also found out that I get this error while trying to connect :
connection error: { [MongoError: auth failed] name: 'MongoError', ok: 0, errmsg: 'auth failed', code: 18 }
Credentials are correct though.
From the error mesasge it seems like you are using invalid auth details
This is most likely happen when you do not create username and password for individual database i.e, db_name in you case.
Check mLabs account and create username and password for db_name database and update your connection string.
According to the error information, as #Astro said, it seems to be caused by using invalid auth user/password which be created for database.
Did you create a new user for connecting the database, not account user for mlab? Such as the figures below shown.
Fig 1. A database user is required for connecting
Fig 2. Users list for the database
Hope it helps.
I figured out the issue, it wasn't an issue with the credentials. It was an issue with the mongoose version. The mongoose version I used didn't support the authentication. I had to remove the package and reinstall the latest version. with
node install mongoose#latest
Hope it helps someone. And thanks for the answers :)
I'm running py2neo 2.0.4 on a remote Neo4j 2.1.6 database. I'm able to connect to the database with some commands, but not with all.
Using the same connection uri for both instances:
This works fine.
test = self.graph_db.find_one('Node')
This does not.
test = self.graph_db.cypher.execute('MATCH (n) RETURN n LIMIT 1')
Regardless of the actual contents of the query, I get the same connection refused results.
With the help of my service provider for Neo4j, we were able to determine the error and a fix.
This is a known flaw in pre-2.2 Neo4j. To resolve this error, use the py2neo rewrite function.
py2neo.rewrite(('http', '0.0.0.0', 7474, ('https', {host}, {port}))