I am evaluating Talend and I have little experience using the tool. My question is regarding audit. Does Talend offer a way to run with an audit option that extracts the source data, transforms it and then compares the transformed data to the existing target data? I would like a report that tells me which records would have triggered an update if the audit option had not prevented it.
I know that ETL's are triggered on change but I would want to run this audit without regard to changed timestamps. That is, a query would specify what source records to audit.
I have done a search of the talend documentation but nothing jumped out at me.
Thank you.
EDIT
Looking outside of Talend, I found where Tim Mitchell wrote:
While I have not yet found an auditing framework with enough
customization to suit me, I have learned that it is possible to audit
ETL processes in a customized way without reinventing the wheel every
time. I keep on hand a common (but never set in stone) set of table
definitions and supporting logic to shorten the path to the following
auditing objectives:
Simple aggregate auditing of row counts, financial data, and other key metrics
Documentation templates for source-to-target mappings and transformation logic
Lightweight auditing of batch-level changes
Full auditing of every change made in the transformation process
So I guess that auditing is on me.
Related
We're using Tableau 10.5.6. I used a reporting tool years ago called Oracle Sales Analyzer. In that tool you could get to the queries generated by the reports and graphs you created through back-end catalogs using their command line.
There you could rewrite the query to be more efficient by fine-tuning the code if you needed. It was a very cool feature of that reporting tool for geeks like me who like to dive into the back end of the product and tune it at a very low level.
My question is, does Tableau have any of this type of facility? Is there a way to get to the queries that get stored once you create a report or a graph. Also is there command line where you can access these catalogs if they exist? Otherwise are these queries just stored in ASCII flat files that can be accessed by a user.
Thanks!
There are two ways that Tableau will query a database.
Option 1: Custom SQL
In your data source, you paste in the sql you have written and Tableau will pass that query through to the database. This gives you complete control over the sql, including adding any indexing hints you may want. See https://onlinehelp.tableau.com/current/pro/desktop/en-us/customsql.html
Option 2: Use the Tableau data source designer
This is what many people do. Here, you visually design your data source with the joins. Tableau translates that design into what the Hyper engine considers to be the most effective way to run the query. Sometimes, Hyper translates that into a regular sql statement. Sometimes it does some additional things to help boost performance, like breaking it up into different queries. A lot depends on the db engine you are connecting to. There is no "sql" stored in a flat file for this. Tableau just translates your design at run-time. The Hyper engine does a good job with fine-tuning, assuming you have an efficient database design with proper indexing and current table statistics.
There is a way to see the sql from option 2 at run-time using Performance Recording. Performance Recording keeps track of each step of the visualization process and will spit out the sql statement(s) that Tableau ran to generate your dataset. The sql is not stored in the twb file though, it's a run-time analysis.
I have a job in talend open studio which is working fine, it conects a tMSSqlinput to a tMap then tMysqlOutput, very straight forward. My problem is that i need this job running on daily basis, but only run when a new record is created or modified...any help is highly aprecciated!
It seems that you are searching for a Change Data Capture Tool for Talend.
Unfortunately it is only available on the licenced product.
To implement your need, you do have several ways. I want to show the most popular ones.
CDC from Talend
As Corentin said correctly, you could choose to use CDC (Change Data Capture) from Talend if you use the subscription version.
CDC of MSSQL
Alternatively you can check if you can activate or use CDC in your MSSQL server. This depends on your license. If it is possible, you can use the function to identify new elements and proceed them.
Triggers
Also you can create triggers on your database (if you have access to it). For example, creating a trigger for the cases INSERT, UPDATE, DELETE would help you getting the deltas. Then you could store those records separately or their IDs.
Software driven / API
If your database is connected to a software and you have developers around, you could ask for a service which identifies records on insert / update / delete and shows them to you. This could be done e.g. in a REST interface.
Delta via ID
If the primary key is an ID and it is set to autoincrement, you could also check your MySQL table for the biggest number and only SELECT those from the source which have a bigger ID than you have already got. This depends of course from the database layout.
I am interested in keeping a running history of every change which has happened on some tables in my database, thus being able to reconstruct historical states of the database for analysis purposes.
I am using Postgres, and this MVCC thing just seems like I should be able to exploit it for this purpose but I cannot find any documentation to support this. Can I do it? Is there a better way?
Any input is appreciated!
UPD
I have marked Denis' response as the answer, because he did in fact answer whether MVCC is what I want which was the question. However, the strategy I have settled on is detailed below in case anyone finds it useful:
The Postgres feature that does what I want: online backup/point in time recovery.
http://www.postgresql.org/docs/8.1/static/backup-online.html explains how to use this feature but essentially you can set this "write ahead log" to archive mode, take a snapshot of the database (say, before it goes live), then continually archive the WAL. You can then use log replay to recall the state of the database at any time, with the side benefit of having a warm standby if you choose (by continually replaying the new WALs on your standby server).
Perhaps this method is not as elegant as other ways of keeping a history, since you need to actually build the database for every point in time you wish to query, however it looks extremely easy to set up and loses zero information. That means when I have the time to improve my handling of historical data, I'll have everything and will therefore be able to transform my clunky system to a more elegant system.
One key fact that makes this so perfect is that my "valid time" is the same as my "transaction time" for the specific application- if this were not the case I would only be capturing "transaction time".
Before I found out about the WAL, I was considering just taking daily snapshots or something but the large size requirement and data loss involved did not sit well with me.
For a quick way to get up and running without compromising my data retention from the outset, this seems like the perfect solution.
Time Travel
PostgreSQL used to have just this feature, and called it "Time Travel". See the old documentation.
There's somewhat similar functionality in the spi contrib module that you might want to check out.
Composite type audit trigger
What I usually do instead is to use triggers to log changes along with timestamps to archival tables, and query against those. If the table structure isn't going to change you can use something like:
CREATE TABLE sometable_history(
command_tag text not null check (command_tag IN ('INSERT','DELETE','UPDATE','TRUNCATE')),
new_content sometable,
change_time timestamp with time zone
);
and your versioning trigger can just insert into sometable_history(TG_OP,NEW,current_timestamp) (with a different CASE for DELETE, where NEW is not defined).
hstore audit trigger
That gets painful if the schema changes to add new NOT NULL columns though. If you expect to do anything like that consider using a hstore to archive the columns, instead of a composite type. I've already added an implementation of that on the PostgreSQL wiki already.
PITR
If you want to avoid impact on your master database (growing tables, etc), you can alternately use continuous archiving and point-in-time recovery to log WAL files that can, using a recovery.conf, be replayed to any moment in time. Note that WAL files are big and they include not only the tuples you changed, but VACUUM activity and other details. You'll want to run them through clearxlogtail since they can have garbage data on the end if they're partial segments from an archive timeout, then you'll want to compress them heavily for long term storage.
I am using Postgres, and this MVCC thing just seems like I should be able to exploit it for this purpose but I cannot find any documentation to support this. Can I do it?
Not really. There are tools to see dead rows, because auto-vacuuming is so that will eventually be reclaimed.
Is there a better way?
If I get your question right, you're looking into logging slowly changing dimensions.
You might find this recent related thread interesting:
Temporal database design, with a twist (live vs draft rows)
I'm not aware of any tools/products that are built for that purpose.
While this may not be exactly what you're asking for, you can configure Postgresql to log ddl changes. Setting the log_line_prefix parameter (try including %d, %m, and %u) and setting the log_statement parameter to ddl should give you a reasonable history of who made what ddl changes and when.
Having said that, I don't believe logging ddl to be foolproof. For example, consider a situation where:
Multiple schemas have a table with the same name,
one of the tables is altered, and
the ddl doesn't fully qualify the table name (relying on the search path to get it right),
then it may not be possible to know from the log which table was actually altered.
Another option might be to log ddl as above but then have a watcher program perform a pg_dump of the database schema whenever a ddl entry get's logged. You could even compare the new dump with the previous dump and extract just the objects that were changed.
I have a huge SQL script which i need to analyse. It would be really helpful if i could find a way which can generate a call tree; ie, to see which all procedures are called from a particular procedure. a perl based example is here, http://sqlblog.com/blogs/linchi_shea/archive/2009/10/23/find-the-complete-call-tree-for-a-stored-procedure.aspx
but i need a tool to analyse the text file (.sql file), not the procedure stored in the database. due to some reasons i will not be able to create the whole set of procedures in the database and use the above mentioned tool.
please respond if you have come across any ide/tool with this feature.
Probably not very helpful, as it violates your request for a "offline" sql file, text based parsing tool, but wanted to throw this redgate tool out there that I have used with great success in the past; RedGate Sql Dependency Tracker. It works very well and does a good job mapping out your objects and all their dependencies (definable as to what you want mapped). But it does require a database with all of the existing objects in place to work properly. :(
If you can't find one out there, I guess you could maybe do some script/macro text parsing if all the procedure calls are easily defined and predictable in the file. AutoHotKey is a great general purpose scripting tool/framework, and there are a few sql based scripts out there...just not one exactly like you are looking for that I have seen.
We're considering using SSIS to maintain a PostgreSql data warehouse. I've used it before between SQL Servers with no problems, but am having a lot of difficulty getting it to play nicely with Postgres. I’m using the evaluation version of the OLEDB PGNP data provider (http://www.postgresql.org/about/news.1004).
I wanted to start with something simple like UPSERT on the fact table (10k-15k rows are updated/inserted daily), but this is proving very difficult (not to mention I’ll want to use surrogate keys in the future).
I’ve attempted (Link) and (http://consultingblogs.emc.com/jamiethomson/archive/2006/09/12/SSIS_3A00_-Checking-if-a-row-exists-and-if-it-does_2C00_-has-it-changed.aspx) which are effectively the same (except I don’t really understand the union all at the end when I’m trying to upsert) But I run into the same problem with parameters when doing the update using a OLEDb command – which I tried to overcome using (http://technet.microsoft.com/en-us/library/ms141773.aspx) but that just doesn’t seem to work, I get a validation error –
The external columns for complent.... are out of sync with the datasource columns... external column “Param_2” needs to be removed from the external columns.
(this error is repeated for the first two parameters as well – never came across this using the sql connection as it supports named parameters)
Has anyone come across this?
AND:
The fact that this simple task is apparently so difficult to do in SSIS suggests I’m using the wrong tool for the job - is there a better (and still flexible) way of doing this? Or would another ETL package be better for use between two Postgres database? -Other options include any listed on (http://en.wikipedia.org/wiki/Extract,_transform,_load#Open-source_ETL_frameworks). I could just go and write a load of SQL to do this for me, but I wanted a neat and easily maintainable solution.
I have used the Slowly Changing Dimension wizard for this with good success. It may give you what you are looking for especially with the Wizard
http://msdn.microsoft.com/en-us/library/ms141715.aspx
The External Columns Out Of Sync: SSIS is Case Sensitive - I encountered this issue multiple times and it makes me want to pull my hair out.
This simple task is going to take some work either way. SSIS is by no means an enterprise class ETL product yet, but it does give you some quick and easy functionality, and is sufficient for most ETL work. I guess it is also about your level of comfort with it as well.
SCD is way too slow for what I want. I need to use set based sql.
It turned out that a lot of my problems were with bugs in the provider.
I opened a forum topic (http://www.pgoledb.com/forum/viewtopic.php?f=4&t=49) and had a useful discussion with the moderator/support/developer person.
Also Postgres doesn't let you do cross db querys, so I solved the problem this way:
Data Source from Production DB to a temp Archive DB table
Run set based query between temp table and archive table
Truncate temp table
Note that the temp table is not atchally a temp table, but a copy of the archive table schema to temporarily stored data in.
Took a while, but I got there in the end.
This simple task is going to take some work either way. SSIS is by no means an enterprise class ETL product yet, but it does give you some quick and easy functionality, and is sufficient for most ETL work. I guess it is also about your level of comfort with it as well.
What enterprise ETL solution would you suggest?