I've been trying to use Continuous Query Notification (CQN) in python script to get notification from database about changes that were made to a specific table.
I have followed tutorial from this link here
https://python-oracledb.readthedocs.io/en/latest/user_guide/cqn.html
Connection to oracle database was successful and I can query the table to get results but I can't get any message from callback function that looks like this
def cqn_callback(message):
print("Notification:")
for query in message.queries:
for tab in query.tables:
print("Table:", tab.name)
print("Operation:", tab.operation)
for row in tab.rows:
if row.operation & oracledb.OPCODE_INSERT:
print("INSERT of rowid:", row.rowid)
if row.operation & oracledb.OPCODE_DELETE:
print("DELETE of rowid:", row.rowid)
subscr = connection.subscribe(callback=cqn_callback,
operations=oracledb.OPCODE_INSERT | oracledb.OPCODE_DELETE,
qos=oracledb.SUBSCR_QOS_QUERY | oracledb.SUBSCR_QOS_ROWIDS)
subscr.registerquery("select * from regions")
input("Hit enter to stop CQN demo\n")
I can see that the registration was created in the database after I run the script but I just don't receive any message about insert or delete after I perform any of those operations through SQL* Plus or SQL Developer.
I am reading other questions and blogs about this functionality but currently without success, so if anyone has any recommendations or has encountered similar problem, please comment or answer here.
Oracle database 12C from docker
Python version is 3.10.7
I am running it in thick mode and for oracle client libraries I am using this command
oracledb.init_oracle_client(lib_dir = ".../instantclient_21_3"
P.S This is my first time posting a question here so if I didn't correctly follow a structure or rules of asking a question please correct me, thanks in advance :)
Please take a look at the requirements for CQN in the documentation. Note in particular the fact that the database needs to connect back to the application. If this cannot be done no notifications will take place even though the registration is successful with the database. With Oracle Database 19.4 a new mode was introduced which eliminates this requirement, but since you are still using 12c that won't work for you. You will need to ensure that the database can connect back to the application -- opening up any ports, ensuring that an IP address is directly specified in the parameters or an IP address can be looked up from the name of the client machine connecting to the database, etc.
Related
I want to use Telegram client API.
I want to Run run_until_disconnected() for getting all messages in 24 hours and save them in Database. This Part is fine , I Wrote the code and its working fine . after some operations on the messages database , I want to send the result of that operation as a message to telegram (to channel or User). i wrote the code of sending message too but when i wanted to use , i get error of database is locked or session is locked...
What should I Do?
Please Read :: https://docs.telethon.dev/en/latest/quick-references/faq.html#id9
Solution according to docs :
if you need two clients, use two sessions. If the problem persists and you’re on Linux, you can use fuser my.session to find out the process locking the file. As a last resort, you can reboot your system.
If you really dislike SQLite, use a different session storage. There is an entire section covering that at Session Files.
Anyone use the Python Connector to connect to Snowflake, specifically using https://<your_okta_account_name>.okta.com (i.e. the URL endpoint for Okta) to authenticate through native Okta.? I keep getting the error below, but I know it is the correct password/username. I am able to login fine via 'external browser" (but not through cloud9, nor do I want to continue this way)
Failed to connect to DB: appfolio.snowflakecomputing.com:443. Incorrect username or password was specified.
I have the following variables set up and I know I have correct password/username so going a little crazy , anyone here have this issue?
authenticator = 'https://company.okta.com'
user='user.name#company.com',
password= "password",
account='company'
People are having the same error (with & without MFA) but no solution was posted on snowflakes community board: https://community.snowflake.com/s/question/0D50Z00009JJKZGSA5/unable-to-connect-to-snowflake-using-aws-lambda
I am trying to identify the number of connections to a postgres database. This is in context of the connection limit on heroku-postgres for dev and hobby plans, which is limited to 20. I have a python django application using the database. I want to understand what constitute a connection. Will each instance of an user using the application count as one connection ? Or The connection from the application to the database is counted as one.
To figure this out I tried the following.
Opened multiple instances of the application from different clients (3 separate machines).
Connected to the database using an online Adminer tool(https://adminer.cs50.net/)
Connected to the database using pgAdmin installed in my local system.
Created and ran dataclips (query reports) on the database from heroku.
Ran the following query from adminer and pgadmin to observe the number of records:
select * from pg_stat_activity where datname ='db_name';
Initial it seemed there was a new record for each for the instance of the application I opened and 1 record for the adminer instance. After some time the query from adminer was showing 6 records (2 connections for adminer, 2 for the pgadmin and 2 for the web-app).
Unfortunately I am still not sure if each instance of users using my web application would be counted as a connection or will all connections to the database from the web app be counted as one ?
Thanks in advance.
Best Regards!
Using PostgreSQL parameters to log connections and disconnections (with right log_line_prefix parameter to have client information) should help:
log_connections (boolean)
Causes each attempted connection to the server to be logged, as well as successful completion of client authentication. Only
superusers can change this parameter at session start, and it cannot
be changed at all within a session. The default is off.
log_disconnections (boolean)
Causes session terminations to be logged. The log output provides information similar to log_connections, plus the duration of the
session. Only superusers can change this parameter at session start,
and it cannot be changed at all within a session. The default is off.
The approach I am trying is to write a dynamic script that would generate mirror tables as in Oracle with similar data types in SQL server. Then again, write a dynamic script to insert records to SQL server. The challenge I see is incompatible data types. Has anyone come across similar situation? I am a sql developer but I can learn python if someone can share their similar work.
Have you tried the "SQL Server Import and Export Wizard" in SSMS?
i.e. if you create an empty SQL server database and right click on it in SSMS then one of the "tasks" menu options is "Import Data..." which starts up the "SQL Server Import and Export Wizard". This builds a once-off SSIS package .. which can be saved if you want to re-use.
There is a data source option for "Microsoft OLE DB Provider for Oracle".
You might have a better Oracle OLE DB Provider available also to try.
The will require Oracle client software to be available.
I haven't actually tried this (Oracle to SQL*Server) so am not sure if reasonable or not.
How many tables, columns?
Oracle DB may also have Views, triggers, constraints, Indexes, Functions, Packages, sequence generators, synonyms.
I used linked server, got all the metadata of the tables from dba_tab_columns in Oracle. Wrote script to create tables based on the metadata. I needed to use SSIS script task to save the create table script for source control. Then I wrote sql script to insert data from oracle, handled type differences through script.
I have very little knowledge of rackspace..My client has setup one server at rackspace cloud and saying that he created one database and I have to retrieve data from there , while logging into https://mycloud.rackspace.com/ , I found that server is created at
PublicNet (Internet) 166.78.105.176
and I also can access database via phpmyadmin http://"link"/phpmyadmin
But the problem is I need instance Id of that database from cloud control panel to connect to database as said in http://www.rackspace.com/knowledge_center/article/connecting-to-your-cloud-database , which I am not able to get as I am not able to see database in cloud control panel..
Please help..am I in right direction ? or I am totally in wrong path.
Any suggestions would be helpful me..