'Extract, Transform and Load': Data load processing, normally in the context of data warehouse systems.

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24
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3answers
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Are regular VACUUM ANALYZE still recommended under 9.1?

I'm using PostgreSQL 9.1 on Ubuntu. Are scheduled VACUUM ANALYZE still recommended, or is autovacuum enough to take care of all needs? If the answer is "it depends", then: I have a largish database ...
23
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7answers
10k views

Any Open Source / free ETL out there? [closed]

I was using Pentaho Data Integration even before Pentaho bought it and call it that. I have the last free version. I went on their website recently to see if they had released another version only to ...
19
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3answers
36k views

How do I run a large script with many inserts without running out of memory?

Question: I have a script with around 45 thousand insert from select statements. When I try and run it, I get an error message stating that I have run out of memory. How can I get this script to run? ...
17
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3answers
11k views

What are the arguments in favor of using ELT process over ETL?

I realized that my company uses an ELT (extract-load-transform) process instead of using an ETL (extract-transform-load) process. What are the differences in the two approaches and in which situations ...
9
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4answers
1k views

Is there a standard language/interface for programmatic ETL in SQL Server?

I'm currently in the process of creating ETLs for our data warehouse. We're using SSIS 2008, but we're running into issues, the biggest of which is the difficulty in re-using components. We have ...
9
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2answers
6k views

ETL: extracting from 200 tables - SSIS data flow or custom T-SQL?

Based on my analysis, a complete dimensional model for our data warehouse will require extraction from over 200 source tables. Some of these tables will be extracted as part of an incremental load and ...
9
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2answers
9k views

PostgreSQL for high volume transactions and for Data warehousing

Am quite new to PostgreSQL, I have never done a large deployment using it before. But, I have good experience in enterprise solutions and I want to try and apply some of what I learned using ...
7
votes
4answers
14k views

Quick way to validate two tables against each other

We're doing an ETL process. When all is said and done there are a bunch of tables that should be identical. What is the quickest way to verify that those tables (on two different servers) are in ...
7
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3answers
166 views

Tablespace on ephemeral storage

For performance reasons in some scenarios, e.g. Amazon EC2, you have access to a faster and cheaper storage device, which loses all its data on reboots, so it is called "ephemeral". This question is ...
7
votes
1answer
4k views

Duplicating some rows of a data flow in SSIS

I have a data flow to migrate data from an old database to a new one. The old design had all the data and historical information (changes) stored in a single table with a "version" (incrementing ...
6
votes
3answers
92 views

Azure Data warehouse - User defined function issues

Anyone here had luck with creating and using UDFs on Azure data warehouse database? I am in the middle of migrating an on-prem warehouse from SQL Server 2014 to Azure datawarehouse and I ran into an ...
6
votes
5answers
423 views

SSIS ETL Question/Option

In our current prod environment, when the ETL launches, it first checks an environmental variable at the OS level which tells it where the "config" database and table is for it to get the necessary ...
6
votes
1answer
126 views

How do you index alphanumeric foreign keys on large fact tables?

I have a field that is an alphanumeric field that ideally is a encrypted field for a non-unique identifier. It's used to relate other rather large fact tables in a many-to-many relationship. I do not ...
6
votes
2answers
116 views

SQL server Database statistics degrading after execution

I have been experiencing timeouts while querying my SQL Server DB in particular one table. I tried updating the statistics and it fixed the performance issues for a couple of days. I started digging ...
5
votes
1answer
66 views

Are there practical scenarios where inserts + deletes are faster than updates? (SQL Server)

I'm just wondering if there are common scenarios where an insert/ delete combination is faster than an update else insert function. Here is my specific example. I have to update a database with ...
5
votes
1answer
1k views

SQL 2008: agent job error in opening excel files using DTS package

I have a SQL 2008 server (SQL2008S1) with Excel installed on it. I had to migrate databases and DTS packages from a SQL 2000 server (SQL2000S2) to this server. 1 DTS package is trying to access an ...
5
votes
1answer
134 views

Is there a non-DDL way to preserve back-references when staging data into production?

Let's say I've got this hypothetical schema: Source (OLTP) DB: Table Orders ------------ OrderID int IDENTITY (PK), CustomerID int NOT NULL, OrderAmount decimal NOT NULL Destination (DSS) DB: ...
5
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1answer
6k views

MySQL failing and very slow on importing a large file

I have a 47 GB MySQL dump of a single table: http://dumps.wikimedia.org/commonswiki/latest/commonswiki-latest-image.sql.gz I ultimately want it into PostgreSQL, but since I didn't figure out an easy ...
5
votes
2answers
8k views

Importing a large column (8000 chars) from Excel using SSIS

I'm trying to set up a regular import of an excel spreadsheet that we get from a vendor. I'm using SQL 2008 R2 SSIS to import it into a table. The problem connection manager is an OLE DB connection ...
4
votes
3answers
1k views

How can I make my SSIS process consume more resources and run faster?

I have a daily ETL process in SSIS that builds my warehouse so we can provide day-over-day reports. I have two servers - one for SSIS and the other for the SQL Server Database. The SSIS server ...
4
votes
2answers
107 views

data warehouse automation tool: benefit or bane? [closed]

Today while investigating ETL and data warehouse solutions like Kettle, I came across a new concept (for me) called data warehouse automation tool. I also looked at the white paper here, which ...
4
votes
1answer
396 views

Dodgy causes of ORA-12549?

I am dealing with a rather massive ETL processing which keeps throwing me the ORA-12549 error. Have been looking for problems in the database so far and nothing. The DBA says the database is "fine" - ...
4
votes
3answers
99 views

is automated data movement via Excel considered ETL?

I am wondering if informal methods of automatically extracting, transforming, and loaded data constitute "ETL." For example, I code Excel VBA to extract from databases onto a spreadsheet, transform ...
4
votes
2answers
101 views

Query “last” records in a table with non-sequential key fields

My goal is to clone a table from an Oracle database to a SQL Server database every midnight. I am using Talend Data Integration for this task. The problem is that this table has around 70 million ...
4
votes
1answer
489 views

SSIS Multicast performance question

I'm wondering how multicast actually works. So here is my setup. I have one source flat file(csv) of about 100k rows, maybe about 250-300 columns, and I'm multicasting that file into 7 one-to-one ...
4
votes
4answers
3k views

best ETL design to transfer transaction tables records into the data-warehouse

I have 2 type of tables to populate the data-warehouse with every day, lookup tables or configuration tables with few 100s records, and thats easy where i just truncate and refill the table. but for ...
4
votes
1answer
617 views

Methodology & Architecture to Create ETL Process

What book or webpage can I read the architecture and methodology for creating ETL process? In other words, I'm looking for "how to do it" to create a ETL process when you have many source system to ...
4
votes
1answer
515 views

Is there a standard way to replace codes with values from a lookup table for reporting or analytics?

Suppose I have a "main" table that was probably heavily normalized and consists largely of columns that merely contain codes that are lookups into other tables (they are probably foreign keys but feel ...
4
votes
4answers
2k views

What options exist for copying data between servers on a regular basis?

My apologies if this has already been answered. I've searched SO and of course here on DBA, and am surprised to find no close matches. Specifically, I'm looking for a solution which survives schema ...
4
votes
1answer
473 views

Large difference in disk space used by partitions

I have a partitioned table that contains about 155 million records total. It's partitioned by year and the partitions for both the current and previous years contain about 25 million records each. ...
4
votes
2answers
609 views

What is the best practice for mapping from natural keys to integer-based keys? (ETL)

This question originates more from an "enterprise architecture" point of view. (Reason being, our company is just starting to get into data management, and actually having DBA's -- I know, horrific ...
3
votes
3answers
843 views

How can I use an ETL?

I know that those letters mean Extract, Transform, and Load. But, when I used it at first, I thought that during the Transform phase I could do plenty of different joins on data that I've extracted ...
3
votes
3answers
7k views

Inserting rows into other table whilst preserving IDENTITY

I'm performing ETL logic on a SQL Server table. I'm going to be synchronizing data from one table to another. For all of the records that need to be added to the target table based on the source ...
3
votes
1answer
175 views

Replace column values?

I recently got into SSIS and haven't been able to find what I am trying to achieve anywhere on the web. I am trying to take some rows as input, and then replace one specific column's value with ...
3
votes
2answers
17k views

Error on SELECT - Primary filegroup is full

A SQL Server 2008 R2 database view unions several transaction table. The query has been slow over the couple of months and the dev team is planning to recreate the query. I need to ETL the results ...
3
votes
1answer
1k views

Does surrogate key assignment for a fact table require that the source data has natural keys?

Let's say I have a simple OLTP database with orders, products, and customers: And from it, I am building a data mart with an orders fact table, product dimension, customer dimension, and date ...
3
votes
3answers
2k views

Is it good idea to change Simple Recover Model into Bulk-Logged on ETL system?

We are having an ETL process which inserts lots of data into tables. This database is set to Simple Recovery Model and the transaction log is growing a lot. I was thinking that would it help to set ...
3
votes
1answer
132 views

Stored procedure deployment - push or pull into database? [closed]

Using stored procedures as part of an ETL process to populate tables in another database, which method would be considered a best practice (if any) in terms of deployment, maintenance, visibility and ...
3
votes
1answer
253 views

Metadata Headache

A process that I don't have control over is dropping and re-creating tables in a MySQL database every night. This wouldn't be a problem (I think), if it re-created the tables identically every time. ...
3
votes
2answers
1k views

Is this a good strategy for importing a large amount of data and decomposing as an ETL?

I have a set of five tables (a highly decomposed schema for an ETL if I understand the nomenclature) that I'm going to load via bulk import, then run some inserts from those five tables into a SLEW of ...
3
votes
0answers
57 views

How do I load data from a single table to multiple tables & keep referential integrity

Using SQL Server 2008R2. I have a single table with a bunch of columns. I have built a new database with multiple tables to copy the data too. How do I copy the data, and still keep the ...
3
votes
0answers
920 views

SSIS Recordset Destination error

I have an SSIS package targeted at SQL Server 2012. I have it deployed into the Stored Packages in Integration Services and then have a SQL Server Agent job which executes it. The first part of the ...
2
votes
3answers
2k views

ETL: extraction strategy for 200 source databases

What is the best extraction strategy for approximately 200 SQL Server 2005 source databases (same schema) for a daily load into a staging area in preparation for data warehouse cleansing, ...
2
votes
1answer
61 views

Introduce or not introduce SSIS to an ETL project [closed]

Given is an ETL process that works fine using traditional SQL. The process is well optimized making use of ALTER TABLE permissions and performing partition switching, index creation, partition ...
2
votes
2answers
1k views

What is a good solution for reliably transferring data between SQL Server and PostgreSQL? [closed]

In analyzing some of our business data, we're realizing that we need to join data across disparate data sources. For example, our application data is warehoused in Postgres (ported from MongoDB via ...
2
votes
1answer
124 views

What is the best way to import this non-standard text file into SQL Server?

I have a text file that is generated daily. It is a fixed width format with one frustrating exception. The third column (NAME) has a variable width. The column is always exactly as long as the longest ...
2
votes
3answers
29 views

Data Warehouse attribute that describes its timeframe?

I am writing a document about a Data Warehouse system, and would like to know if is there a single word (noun) that describes the DW attribute of how many time it contains? I mean, if a DW contains ...
2
votes
2answers
902 views

How to pass parameter in select query(In with clause) and not in where condition in SQl Server SSIS Package?

I want to pass a parameter (@date1) in my SSIS OLE DB Source so I created a variable and I tried to pass the parameter using '?' but it's showing 'Syntax error, permission violation or other ...
2
votes
2answers
727 views

How to perform ETL from RDBMS to Neo4j

I have a mature 50+ tables web application based on mySQL. In order to do some advanced data mining I want to use Neo4j and the goodnes of cypher. However I'm having a hard time migrating my data from ...
2
votes
1answer
634 views

What are the best practices for ETL of data from one OLTP system to another, Part 2?

Ok, I originally started a question a ways back called "What are the best practices for ETL of data from one OLTP system to another?". And as you can probably tell from most of my questions so far, ...