Is there a way to get table usage stats like number of select, insert, update, delete on a specific table without using auditing?
version: ASE-16 EBF 27304
Thanks in advance!
Related
I would like to use a timetravel feature on snowflake and restore the original table.
I've deleted and created the table using following command:
DROP TABLE "SOCIAL_LIVE"
CREATE TABLE "SOCIAL_LIVE" (...)
I would like to go back to the original table before dropping table.
I've used following code (hid the transaction ID to 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx')
Select "BW"."PUBLIC"."SOCIAL_LIVE".* From "BW"."PUBLIC"."SOCIAL_LIVE";
select * from SOCIAL_LIVE before(statement => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx');
Received an error message:
Statement xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx cannot be used to specify time for time travel query.
How can we go back to the original table and restore it on snowflake?
The documentation states:
After dropping a table, creating a table with the same name creates a
new version of the table. The dropped version of the previous table
can still be restored using the following method:
Rename the current version of the table to a different name.
Use the UNDROP TABLE command to restore the previous version.
If you need further information, this page is useful:
https://docs.snowflake.net/manuals/sql-reference/sql/drop-table.html#usage-notes
You will need to undrop the table in order to access that data, though. Time-travel is not maintained by name alone. So, once you dropped and recreated the table, the new table has its own, new time travel.
Looks like there's 3 common reasons that error is seen, with solutions:
the table has been dropped and recreated
see this answer
the time travel period has been exceeded
no solution: target a statement within the time travel period for the table
the wrong statement type is being targeted
only certain statement types can be targeted. Currently, these include SELECT, BEGIN, COMMIT, and DML (INSERT, UPDATE etc). See documentation here.
Statement xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx cannot be used to specify time for time travel query.
Usually we will get above error when we trying to travel behind the object creation time. Try with time travel option with offset option.
I went over the documentation for Clickhouse and I did not see the option to UPDATE nor DELETE. It seems to me its an append only system.
Is there a possibility to update existing records or is there some workaround like truncating a partition that has records in it that have changed and then re-insering the entire data for that partition?
Through Alter query in clickhouse we can able to delete/update the rows in a table.
For delete: Query should be constructed as
ALTER TABLE testing.Employee DELETE WHERE Emp_Name='user4';
For Update: Query should be constructed as
ALTER TABLE testing.employee UPDATE AssignedUser='sunil' where AssignedUser='sunny';
UPDATE: This answer is no longer true, look at https://stackoverflow.com/a/55298764/3583139
ClickHouse doesn't support real UPDATE/DELETE.
But there are few possible workarounds:
Trying to organize data in a way, that is need not to be updated.
You could write log of update events to a table, and then calculate reports from that log. So, instead of updating existing records, you append new records to a table.
Using table engine that do data transformation in background during merges. For example, (rather specific) CollapsingMergeTree table engine:
https://clickhouse.yandex/reference_en.html#CollapsingMergeTree
Also there are ReplacingMergeTree table engine (not documented yet, you could find example in tests: https://github.com/yandex/ClickHouse/blob/master/dbms/tests/queries/0_stateless/00325_replacing_merge_tree.sql)
Drawback is that you don't know, when background merge will be done, and will it ever be done.
Also look at samdoj's answer.
You can drop and create new tables, but depending on their size this might be very time consuming. You could do something like this:
For deletion, something like this could work.
INSERT INTO tableTemp SELECT * from table1 WHERE rowID != #targetRowID;
DROP table1;
INSERT INTO table1 SELECT * from tableTemp;
Similarly, to update a row, you could first delete it in this manner, and then add it.
Functionality to UPDATE or DELETE data has been added in recent ClickHouse releases, but its expensive batch operation which can't be performed too frequently.
See https://clickhouse.yandex/docs/en/query_language/alter/#mutations for more details.
It's an old question, but updates are now supported in Clickhouse. Note it's not recommended to do many small changes for performance reasons. But it is possible.
Syntax:
ALTER TABLE [db.]table UPDATE column1 = expr1 [, ...] WHERE filter_expr
Clickhouse UPDATE documentation
I want to add +1 for views column when a visitor view a page. I decided to make it using trigger, but i don't know how to make a trigger on select, I see examples on delete, update and insert but no one mentioned select. anyone can help me with simple example?
There is no such thing as a trigger for 'SELECT' in SQL Server. As an alternative you could create a stored procedure that does the SELECT and UPDATEs your view counts.
short answer is no,there is nothing like trigger on SELECT.moreover
If the data you have if so sensitive and you want to implement access audit in t-sql (which not the best design idea), you can do the following:
Remove SELECT access to the table from all users
Create stored procedure to retrieve data from the table
Implement custom audit inside of the above stored proc.
you can view this link here to read about it more
I am trying to create a generic trigger in SQL Server which can copy all column data from Table A and insert them in corresponding fields in Table B.
There are few problems I am facing.
I need this copy to occur under three conditions : INSERT, DELETE and UPDATE.
The trigger needs to be triggered after CUD operations. using AFTER throws SQL error saying ntext etc are not supported in inserted. How do I resolve this error?
Instead of if used can work for INSERT but not for delete. Is there a way to do this for delete operations?
Is there a way I can write a generic code inside the trigger which can work for all sorts of tables (we can assume that all the columns in table a exists in column b)
I am not well versed with triggers or for that matter DDL in SQL Server.
Appreciate if some can provide me some solutions.
Thanks
Ben
CREATE TRIGGER (Transact-SQL)
Use nvarchar(max) instead of ntext.
You can have an instead of trigger for delete.
You can have one trigger that handles insert/update/delete for one table but you can not connect a trigger to more than one table.
I erroneously delete all the rows from a MS SQL 2000 table that is used in merge replication (the table is on the publisher). I then compounded the issue by using a DTS operation to retrieve the rows from a backup database and repopulate the table.
This has created the following issue:
The delete operation marked the rows for deletion on the clients but the DTS operation bypasses the replication triggers so the imported rows are not marked for insertion on the subscribers. In effect the subscribers lose the data although it is on the publisher.
So I thought "no worries" I will just delete the rows again and then add them correctly via an insert statement and they will then be marked for insertion on the subscribers.
This is my problem:
I cannot delete the DTSed rows because I get a "Cannot insert duplicate key row in object 'MSmerge_tombstone' with unique index 'uc1MSmerge_tombstone'." error. What I would like to do is somehow delete the rows from the table bypassing the merge replication trigger. Is this possible? I don't want to remove and redo the replication because the subscribers are 50+ windows mobile devices.
Edit: I have tried the Truncate Table command. This gives the following error "Cannot truncate table xxxx because it is published for replication"
Have you tried truncating the table?
You may have to truncate the table and reset the ID field back to 0 if you need the inserted rows to have the same ID. If not, just truncate and it should be fine.
You also could look into temporarily dropping the unique index and adding it back when you're done.
Look into sp_mergedummyupdate
Would creating a second table be an option? You could create a second table, populate it with the needed data, add the constraints/indexes, then drop the first table and rename your second table. This should give you the data with the right keys...and it should all consist of SQL statements that are allowed to trickle down the replication. It just isn't probably the best on performance...and definitely would impose some risk.
I haven't tried this first hand in a replicated environment...but it may be at least worth trying out.
Thanks for the tips...I eventually found a solution:
I deleted the merge delete trigger from the table
Deleted the DTSed rows
Recreated the merge delete trigger
Added my rows correctly using an insert statement.
I was a little worried bout fiddling with the merge triggers but every thing appears to be working correctly.