oracle – TNS-00534: Failed to grant connection ownership to child

when I tried to connect to my oracle instance with sql developer, I see this error in logs

TNS-12518: TNS:listener could not hand off client connection
 TNS-12560: TNS:protocol adapter error
  TNS-00534: Failed to grant connection ownership to child
   64-bit Windows Error: 10022: Unknown error

Can someone give me a poit how to solve this error. Note I have 64b client installed.

routing – Can’t start netbox on Oracle Cloud Instance (CentOS 8)

I”m trying to run netbox on CentOS by Oracle Cloud Instance. I installed as described on Documentation, but when I check the service after

(venv) $ python3 runserver --insecure
Performing system checks...

System check identified no issues (0 silenced).
November 17, 2020 - 16:08:13
Django version 3.1.3, using settings 'netbox.settings'
Starting development server at
Quit the server with CONTROL-C.

and opened on browser nothing happened. I also opened ports on firewall

# firewall-cmd --zone=public --permanent --add-service=http
# firewall-cmd --zone=public --permanent --add-service=https
# firewall-cmd --reload

and added Ingress rules on instance ingress rules screenshot.
after I installed nginx and configured it as on Documentation.

(root@home-vpn-instance nginx)# sudo systemctl status nginx
● nginx.service - The nginx HTTP and reverse proxy server
   Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2021-04-09 19:38:09 GMT; 3s ago
  Process: 3892 ExecStart=/usr/sbin/nginx (code=exited, status=0/SUCCESS)
  Process: 3890 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=0/SUCCESS)
  Process: 3888 ExecStartPre=/usr/bin/rm -f /run/ (code=exited, status=0/SUCCESS)
 Main PID: 3894 (nginx)
    Tasks: 3 (limit: 4460)
   Memory: 7.7M
   CGroup: /system.slice/nginx.service
           ├─3894 nginx: master process /usr/sbin/nginx
           ├─3895 nginx: worker process
           └─3896 nginx: worker process

Apr 09 19:38:09 home-vpn-instance systemd(1): Starting The nginx HTTP and reverse proxy server...
Apr 09 19:38:09 home-vpn-instance nginx(3890): nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
Apr 09 19:38:09 home-vpn-instance nginx(3890): nginx: configuration file /etc/nginx/nginx.conf test is successful
Apr 09 19:38:09 home-vpn-instance systemd(1): Started The nginx HTTP and reverse proxy server.

But neither nginx nor netbox aren’t available by address or

So can someone help me to solve this problem?

partitioning – Oracle – Exchange partitions between two List partitioned tables

Need some help here.

I have an ETL process which loads the data into a target table A. We have created another table B which is same as the target table in structure and this table is accessed by reporting team to generate reports. This is done to minimize the downtime for report generation. This way the reports are always accessing the latest data.

Target table B is a List partition table, partitioned on Client ID. ETL team loads data for each client in the respective partition, in Table A.

I tried doing it with Exchange partition: exchange partition mechanism to swap the segments of A and partitioned table B. But couldn’t do it as both tables are List partitioned and Oracle doesn’t like that. I created partitions so as to avoid creating multiple tables (TableA_ClientId) for each Client.

My other option: whenever data is loaded into target table A, rename the table B as table Temp, table B as table A and table A as table Temp.

Can you please suggest a better approach.

I am counfused about when Oracle database won’t do parsing

I am confused about when Oracle database won’t do parsing?
In the AWR report, there is a metrics called “execute to parse”, which means more SQL just execute without parsing when it increases.
But as the Oracle document describe:
“When an application issues a SQL statement, the application makes a parse call to the database to prepare the statement for execution. ”
It seems that everytime a SQL statement is issued, parsing will be called.
So I wandering when Oracle won’t do parsing and make the “execute to parse” become a larger number?
Or I just misunderstood?

What is the difference between start and enable in the Oracle RAC srvctl?

In the Oracle 12c documentation it was not clear what is the difference between the srvctl start and srvctl enable commands for services associated with a database.
In the view dba_service a database that has a service already started, has the column ENABLED with NO, what I noticed is that when a RAC service has already started and you try to enable it, it informs you that it is already enabled.

srvctl enable service -d mydb -s myservice
PRCC-1010: myservice was already enabled
PRCR-1002: Resource ora.mydb.myservice.svc is already enabled 

rman – Does Oracle use rowid to recover from redo log and archives?

I am learning about supplemental logging and this questios has came into my mind. What I have understood is, Oracle just save an image of the modified column in redo logs, that is why we need to enable supplemental logging to use log miner or golden gate for example, then we will have sufficient information to reconstruct the modified rows using sql apply. But when Oracle does not have any supplemental logging enabled, how oracle recover this images during a recover situation, I mean, for example recover database from RMAN, is it by rowid?

query – SQL Analyze – dbms_stats consuming much CPU on Oracle Server

In one bigger DB with many user schemas and big tables I have the devs starting regulary the Analyze select dbms_stats queries , that consume a lot of cpu when started for many users at once. These analyze queries have sometimes over 2-3 Minutes duration time and all of them have COUNT inside and the explain plan shows that the queries use every time table access FULL scan.

/* SQL Analyze(0) */ select /*+  full(t)    parallel(t,5) parallel_index(t,5) dbms_stats

A lot of those queries need to collect statistics, but during this period they consume all of the server CPUs, and I would like to see if they can be optimized.
The queries are similar like in the Doc ID 2552730.1

They have a lot of repetitve substrb(dump(max( and to_char(count( sub-functions for the table columns.

PX Coordinator is starting them parallel, which is ok, before SORT aggregate and after sort agreggate in the explain plan.
Many tables have over 150 million rows.

At the end of the queries we have also TOPN,NIL,NDV methods repeating many times.

Have you maybe encountered same issues and which approach could be taken to optimize those queries if possible. SQL Advisor gave back no recommendations.