Oracle 12c connection error:-Got minus one from a read call - oracle-sqldeveloper

My Sql developer was working fine from long time, suddenly from yesterday when i am trying to reconnect it is giving me following error:-
Status : Failure -Test failed: IO Error: Got minus one from a read call, connect lapse 62991 ms., Authentication lapse 0 ms.
Things I tried to solve the issue:-
Made corresponding changes in sqlnet.ora , listener.ora and tnsnames.ora files
Checked is there are too many open connections to the database service.
Restarted ORACLE service and listener
Firewall related changes
Reinstalled ORACLE

In my case the issue, it is due to a malware. Whenever i am trying to connect to DB port, it was automatically getting changed by malware.
You can also identify the problem by using lsnrctl status command, for further information. You can also see the log file of listener.
Run a full scan on your machine and restart listener, hope that helps.

Related

MongoDB: Error connecting to 127.0.0.1:27017, No connetion could be made because target machine actively refused it

I've been using Mongo for a while now, and I never had any kind of errors. But today, I tried running the mongo command in my terminal and I got the following error:
Error connecting to 127.0.0.1:27017 :: caused by :: No connection could be made because the target machine actively refused it. :
I have my PATH variable for Mongo properly configured in my environment variables as follows:
C:\Program Files\MongoDB\Server\4.4\bin
so I doubt that is the issue. I remember going through my task manager yesterday and I accidentally terminated a program running in the background related to Mongo, but I can't seem to remember exactly what it was called, and I really think that that's the root of my problem, because before having terminated that Mongo program in my task manager I had never ran across this connection problem before.
By terminating a program in the background, I'm going to assume you didn't just end process, otherwise a simple computer restart would fix your issue. And in some cases, that same program would've relaunched when you launched MongoDB. But if you disabled a service and need to find which service needs to be running to be able to connect to your MongDB then I would suggest going through your Windows Services list and seeing which ones you disabled and looking one relating to TCP or SNMP.
This is because MongoDB Wire Protocol is a simple socket-based, request-response style protocol. You communicate with the database server through a regular TCP/IP socket and since you can't remember which one you "terminated" and any number of services related to networking can cause a dependency to be absent, I can't be more specific in helping you determine which one you need to turn back on and you'll have to do it through trial and error but I can at least offer you some guidance, hopefully.
Specifically you can either
Run system configuration using
msconfig
In a run box, navigating to the Services tab, order the list by Date Disabled to find the service that was disabled which correlates with when you when snooping through task manager, or
Run Task manager and navigate to the Services Tab, then Open Services, and order them by Status or by Name, and look for any service that includes TCP/IP, COM+, Port direction, etc. to see which one is disabled and change the configuration from anything but Disabled and then stat it manually and run MongDB again.
It's about as specific as I can get without knowing anything more than you terminated some program running in the background but I hope it helps.
The background process (daemon) for MongoDB is called 'mongod'. It's an executable in your bin directory inside your mongodb installation. You can just execute it in the terminal.
Run:
C:\Program Files\MongoDB\Server\4.4\bin\mongod.exe

Error creating database in Cloudera Impala (Virtual machine)

I have downloaded and started the cloudera virtual machine with impala. At the time of executing the database creation statement, an error related to the catalog and state-store service appeared. Perform the service update from console, however when trying to create a database the following message appears
Could not connect to quickstart.cloudera:21050 (code THRIFTTRANSPORT): TTransportException('Could not connect to quickstart.cloudera:21050',)
I have restarted the following services, but the problem persists: impala-catalog impala-state-store impala-server
Any idea what the problem may be?
The problem was solved alone. Apparently the virtual machine takes longer than I expected to start all services. Once I let it start and wait for a reasonable time, it worked without problems.

Connected To XEPDB1 From SQL Developer [duplicate]

I am using ORACLE database in a windows environment and running a JSP/servlet web application in tomcat. After I do some operations with the application it gives me the following error.
ORA-12518, TNS: listener could not hand off client connection
can any one help me to identify the reason for this problem and propose me a solution?
The solution to this question is to increase the number of processes :
1. Open command prompt
2. sqlplus / as sysdba; //login sysdba user
3. startup force;
4. show parameter processes; // This shows 150(some default) processes allocated, then increase the count to 800
5. alter system set processes=800 scope=spfile;
As Tried and tested.
In my case I found that it is because I haven't closed the database connections properly in my application. Too many connections are open and Oracle can not make more connections. This is a resource limitation. Later when I check with oracle forum I could see some reasons that have mentioned there about this problem. Some of them are.
In most cases this happens due to a network problem.
Your server is probably running out of memory and need to swap memory to disk.One cause can be an Oracle process consuming too much memory.
if it is the second one, please verify large_pool_size or check dispatcher were enough for all connection.
You can refer bellow link for further details.
https://community.oracle.com/message/1874842#1874842
I ran across the same problem, in my case it was a new install of the Oracle client on a new desktop that was giving the error, other clients were working so I knew it wouldn't be a fix to the database configuration. tnsping worked properly but sqlplus failed with the ora-12518 listener error.
I had the tnsnames.ora entry with a SID instead of a service_name, then once I fixed that, still the same error and found I had the wrong service_name as well. Once I fixed that, the error went away.
If from one day to another the issue shows for no apparent reasons, add these following lines at the bottom of the listner.ora file. If your oracle_home environment variable is set like this:
(ORACLE_HOME = C:\oracle11\app\oracle\product\11.2.0\server)
The lines to add are:
ADR_BASE_LISTENER = C:\oracle11\app\oracle\
DIRECT_HANDOFF_TTC_LISTENER=OFF
I had the same problem when executing queries in my application. I'm using Oracle client with Ruby on Rails.
The problem started when I accidentally started several connections with the DB and didn't close them.
When I fixed this, everything started to work fine again.
Hope this helps another one with the same problem.
I experienced the same error after upgrading to Windows 10. I solved it by starting services for Oracle which are stopped.
Start all the services as shown in the following image:
I had the same issue. After restarting all Oracle services it worked again.
same problem encountered for me.
And from oracle server listener log, can see more information.
and I found that the SERVICE_NAME is not match the tnsnames.ora configured Service name. so I changed the application's data source configuration from SID value to Service_NAME value and it fixed.
23-MAY-2019 02:44:21 * (CONNECT_DATA=(CID=(PROGRAM=JDBC Thin Client)(HOST=__jdbc__)(USER=XXXXXX$))(SERVICE_NAME=orclaic)) * (ADDRESS=(PROTOCOL=tcp)(HOST=::1)(PORT=50818)) * establish * orclaic * 12518
TNS-12518: TNS:listener could not hand off client connection
TNS-12560: TNS:protocol adapter error
TNS-00530: Protocol adapter error
64-bit Windows Error: 203: Unknown error
I had the same issue in real time application and the issue gone by itself next day. upon checking, it was found that server ran out of memory due to additional processes running.
So in my case, the reason was server run out of memory
first of all
check the listener log
check the show parameter processes vs select count(*) from v$processes;
increase the process, it may require SGA increase
;

Tableau Vizql, Backgrounder and Data server down

Yesterday our extracts failed to refresh with the following message (image extract_error):
Failure: Failed 1 time. Sign in failed.
Resolution Details: Check the Data Connection page for necessary updates to an access token or embedded credentials.
I verified that all our passwords were unchanged and test connections which were successful.
The tableau dashboards now give an error message saying:
HTTP 404:
Unable to connect to the server "localhost". Check that the server is running and that you have access privileges to the requested database. (image tableau_error)
Further, when I opened the Server Status page, I saw that our one of our two Vizql, backgrounder and data servers were down. We have two of each and only one of them is active for all three of them. (image server_status)
So, I decided to remote desktop into the server and run the tabadmin status -v command and strangely it is showing that all processes are running. (image tabadmin_status)
Finally, I opened a case with Tableau Customer Portal and letting them know about this issue (they asked me send them the log.zip file) but the mean time I was trying to problem solve this issue. Any help would be really appreciated.
After trying a lot of things, one process seemed to work.
Stopped the tableau server
Configured it to run 1 Vizql server process instead of 2
Started the server again
Finally, it worked. The status page now shows all the processes are active.
Hopefully, this helps someone who is facing a similar problem.
This may be caused by a firewall issue. Since tabadmin status -v returned all as "running" the cluster is healthy and this is a false alert. The firewall rules could be allowing just the first port and not the entire range (see https://onlinehelp.tableau.com/current/server/en-us/ports.htm) to respond to requests from the application server to build that fancy table with the green and red boxes.
The firewall can be reverted/altered behind the scenes for a number of reasons, usually windows updates or regular group policy synchronization.
Try disabling the windows firewall (https://www.faqforge.com/windows-server-2016/turn-off-firewall-windows-server-2016/), or add an inbound rule allowing access to all ports if your org policy doesn't allow you to actually turn it off. (Follow the steps here, except use "All Local Ports" instead of "Specific Local Ports" https://www.parallels.com/blogs/ras/configuring-windows-server-firewall-for-parallels-ras/)
I had a similar problem and followed these similar steps that Sravee mentioned above to bring the all processes back to active.
Stopped the server
Change the configuration for VizQL server from 2 to 1
Started the server
Enter the licence key (else the server status page will show unlicensed error)
Note: This does not bring the site back but this step is for 'tricking' VizQL server
Stopped the server again
Change the VizQL configuration from 1 to 2 now.
Start the server
Enter the license key
This steps did bring back the server back to active for us. Posting to see if this helps who faces the same problem. Thank you so much.

index server and statistics server not starting in hana

In SAP HANA index server and statistics server stopped suddenly and not running.
I tried to stop and restart the server by the following commands.
HDB stop
HDB start
But still it is not working. Does anyone know what causes this problem and what is the solution? Thanks in advance.
If the indexserver doesn't start, you cannot logon as SYSTEM (or any other user for that matter). A good way to find out what the reason for the failed start is to check the tracefile for the nameserver, the indexserver and the statisticsserver.
Logon as <sid>adm and change to the tracefile folder via cdtrace.
Then find the tracefiles and use e.g. less to read through them to find the actual error messages.
Alternatively you can use SAP HANA Studio with the emergency connection to review the trace files without terminal access.