Query execution is slow in Teradata FastExport compared to Default Connection - teradata

I have a small doubt on how to use fastexport in production environment.
I have a million rows file and am using fastload to upload it to TD which is taking almost a minute and doing some business logic and when i use fastexport for downloading the table to my local machine/node, it is taking very long time compared to the default version.
Connection Uri i am using is :
jdbc:teradata://server/TMODE=ANSI,CHARSET=UTF8,TYPE=FASTEXPORT
Am i missing anything here. Please suggest.
Thanks

Related

Efficient method to move data from Oracle (SQL Developer) to MS SQL Server

Daily, I query a few tables in SQL Developer, filtering to prior day activity, adding column to date stamp the data, then export to xlsx. Then I manually import each file to a MS SQL Server via SQL Server Import and Export Wizard. Takes many clicks, much waiting...
I'm essentially creating an archive in SQL Server, the application I'm querying overwrites data daily. I'm not a DBA of either database, I use the archived data to do validations and research.
It's tough to get my org to provide additional software, I've been trying to make this work via SQL Developer, SSMS Express ed, and other standard tools.
I'm looking to make this reasonably automated, either via scripts, scheduled tasks, etc. Appreciate suggestions that would work on my current situation, but if that isn't reasonable, and there's a very reasonable alternative, I can go back to the org to request software/access/assistance.
You can use SSIS to import the data directly from Oracle to SQL Server, unless you need the .xlsx files for another purpose. You can also export from Oracle to these, then load to SQL Server from these files if you do need the files. For the date stamp column, a Derived Column can be added within a Data Flow Task using the SSIS GETDATE() function for a timestamp in order to achieve the same result. This function returns a timestamp, and if only the date is necessary the (DT_DBDATE) function can cast it to a date data type that's compatible with this data type of SQL Server. Once you have the SSIS package configured, you can schedule in to run at regular intervals as a SQL Agent job. I'd also recommend installing the SSIS catalog (SSISDB) and using this the source to run the packages from. The following links shed more light on these areas.
SSIS
Connecting to Oracle from SSIS
Data Flow Task
Derived Column Transformation
Creating SQL Server Agent Jobs for SSIS packages
SSIS Catalog
Another option that you may consider (if it is supported in SQL Express) is using the BCP utility, which can be run from command line.
The BCP utility allows you to bulk copy the data from a delimited text file into a SQL Server table.
If you go this approach, things to consider:
Number of Columns in the source file need to match the number of columns in the destination
Data types must match (or be comparable)
Typically, empty strings will be converted to nulls, so you will need to consider if the columns are nullable.
(to name a few - if you want to delve deeper, you might also need to look at custom delimiters between fields and records. Don't forget, commas and line feeds are still valid characters in char type fields).
Anyhow, maybe it will work for you, maybe not. Sure, you might still have to deal with the exporting of the data from Oracle, but it might ease the pain getting the data in.
Have a read:
https://learn.microsoft.com/en-us/sql/tools/bcp-utility?view=sql-server-2017

How to transfer data from SQL Server to Informix and vice versa

I want to transfer tables data from SQL server to Informix and vice versa.
The transferring should be run scheduled and sometimes when the user make a specific action.
I do this operation through delete and insert transactions and it takes along long time through the web between 15 minute to 30 minute.
How to do this operation in easy way taking the performance in consideration?
Say I have
Vacation table in SQL Server and want to transfer all the updated data to the Vacation table in Informix.
and
Permission table in Informix and want to transfer all the updated data to the Permission table in SQL Server.
DISCLAIMER: I am not an SQL Server DBA. However, I have been an Informix DBA for over ten years and can make some recommendations as to its performance.
Disclaimer aside, it sounds like you already have a functional application, but the performance is a show-stopper and that is where you are mainly looking for advice.
There are some technical pieces of information that would be helpful to know, but in their absence, I'm going to make the following assumptions about your environment and application. Please comment or edit your question if I am wrong on any of these.
Database server versions. From the tags, it appears you are using SQL server 2012. However, I cannot determine the Informix server and version. I will assume you are running at least IDS 11.50 or greater.
How the data is being exchanged currently. Are you connecting directly from your .NET application to Informix? I would assume that is the case with SQL Server and will make the same assumption for your Informix connection as well.
Table structures. I assume you have proper indexing on the tables. On the Informix side, dbschema -d *dbname* -t *tablename* will give the basic schema.
If you haven't tried exporting data to CSV and as long as you don't have any compliance concerns doing this, I would suggest loading the data from a comma-delimited file. (Informix normally deals with pipe-delimited files, so you'll either need to adjust the delimiter on the SQL Server side to a pipe | or on the Informix import side). On the Informix end, this would be a
LOAD FROM 'source_file_from_sql_server' DELIMITER '|' INSERT INTO vacation (field1, field2, ..)
For reusability, I would recommend putting this in a stored procedure. Just wrap that load statement inside a BEGIN WORK; and COMMIT WORK; to keep your transactional integrity. Michał Niklas suggested some ways to track changes. If there is any correlation between the transfer of data to the vacation table in Informix and the permission table back in SQL Server, I would propose another option, which is adding a trigger to the vacation table so that you write all new values to a staging table.
With the import logic in a stored procedure, you can fire the import on demand:
EXECUTE PROCEDURE vacation_import();
You also mentioned the need to schedule the import, which can be accomplished with Informix's "dbcron". Using this feature, you'll create a scheduled task that executes vacation_import() periodically as well. If you haven't used this feature before, using OAT will be helpful. You will also want to do some housekeeping with the CSV files. This can be addressed with the system() call, which you can make from stored procedures in Informix.
Some ideas:
Add was_transferred column to source tables setting its default value to 0 (you can use 0/1 instead of false/true).
From source table select data with was_transferred=0.
After transferring data update selected source row, set its was_transferred to 1.
Make table syncro_info with fields like date_start and date_stop. If you discover that there is record with date_stop IS NULL it will mean that you are tranferring data. This will protect you against synchronizing data twice.

Timeout when uploading images

I am currently testing Tridion 2011 and am having problems creating multimedia components with uploaded content (as opposed to external).
I fill out the title, schema, multimedia type, select a file from my system then click save. I get a Saving item... information message then approximately 30 seconds later I will receive a The wait operation timed out message.
There doesn't appear to be any error messages in the C:\Program Files (x86)\Tridion\log directory. Looking at the event viewer I see the following information relating to the save action
Unable to save Component (tcm:4-738361).
The wait operation timed out
Error Code:
0x8004033F (-2147220673)
Call stack:
System.Data.SqlClient.SqlConnection.OnError(SqlException,Boolean,Action`1)
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException,Boolean,Action`1)
System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject,Boolean,Boolean)
System.Data.SqlClient.TdsParser.TryRun(RunBehavior,SqlCommand,SqlDataReader,BulkCopySimpleResultSet,TdsParserStateObject,Boolean&)
System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader,RunBehavior,String)
System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior,RunBehavior,Boolean,Boolean,Int32,Task&,Boolean)
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior,RunBehavior,Boolean,String,TaskCompletionSource`1,Int32,Task&,Boolean)
System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1,String,Boolean,Int32,Boolean)
System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
Tridion.ContentManager.Data.AdoNet.Sql.SqlDatabaseUtilities.SetBinaryContent(Int32,Stream)
Tridion.ContentManager.Data.AdoNet.ContentManagement.ItemDataMapper.Tridion.ContentManager.Data.ContentManagement.IItemDataMapper.SetBinaryContent(Stream,TcmUri)
Tridion.ContentManager.ContentManagement.RepositoryLocalObject.SetBinaryContent(BinaryContent)
Tridion.ContentManager.ContentManagement.Component.OnSaved(SaveEventArgs)
Tridion.ContentManager.IdentifiableObject.Save(SaveEventArgs)
Tridion.ContentManager.ContentManagement.VersionedItem.Save(Boolean)
Tridion.ContentManager.ContentManagement.VersionedItem.Save()
Tridion.ContentManager.BLFacade.ContentManagement.VersionedItemFacade.UpdateAndCheckIn(UserContext,String,Boolean,Boolean)
XMLState.Save
Component.Save
I already have my timeout settings in the Content Manager Snap-In set to high values (more than 10 minutes) due to another issue.
The BINARIES table in the Content Manage Database is 25GB if that helps.
Any ideas? Thanks.
Edit 1
Following suggestions from Bart Koopman, my DBA has rebuilt the indexes but does not reckon the Transaction log has any impact on performance. The problem persists.
Edit 2
I have just found more details of the error
Unable to save Component (tcm:0-0-0).
Timeout expired.
The timeout period elapsed prior to completion of the operation or the server is not responding.
A database error occurred while executing Stored Procedure "EDA_ITEMS_UPDATEBINARYCONTENT".EDA_ITEMS_UPDATEBINARYCONTENT
After taking a look at this procedure it looks like the following statement could be the root cause
SELECT 1 FROM BINARIES WHERE ID = #iBINARY_ID AND CONTENT IS NULL
I execute it manually with #iBINARY_ID as -1 and after 2 minutes it still hasn't completed. I assume that when I insert a new multimedia component the query will be something similar (i.e. the id will not exist in the table).
The BINARIES table currently has a NON-CLUSTERED Primary Key. Maybe the solution would be to change this to a CLUSTERED Primary Key? However, I assume it is NON-CLUSTERED for a reason.
Just had a response from SDL customer support. Apparently this is a known issue related to statistics and the chosen query plan.
Running the following statement manually from SQL Server Management Studio fixes the problem (it didn't even need to complete for me)
SELECT 1 FROM BINARIES WHERE ID = -1 AND CONTENT IS NULL
Hope this helps someone else out!
Timeouts on database operations are usually an indication of a misconfiguration or a lack of maintenance. By increasing the timeout you are just working around the problem rather than solving it.
With a binaries table that big you will want to make sure you have proper database setup with data files that are separated from your log files (separated on different physical partitions/disks) and possibly even multiple data files on multiple physical partitions to take advantage of performance gains.
Next to that you will want to assure that the standard database maintenance is performed daily/hourly. Things like backing up and truncating the transaction log every hour will greatly improve your database performance (on MS SQL Server a transaction log of more than 1GB slows the database down drastically, you should always try to keep it below that size through timely backup/trucate). Updating statistics and rebuilding indexes is also something you should not forget on a regular basis.

Can I read and write to a SQLite database concurrently from multiple connections?

I have a SQLite database that is used by two processes. I am wondering, with the most recent version of SQLite, while one process (connection) starts a transaction to write to the database will the other process be able to read from the database simultaneously?
I collected information from various sources, mostly from sqlite.org, and put them together:
First, by default, multiple processes can have the same SQLite database open at the same time, and several read accesses can be satisfied in parallel.
In case of writing, a single write to the database locks the database for a short time, nothing, even reading, can access the database file at all.
Beginning with version 3.7.0, a new “Write Ahead Logging” (WAL) option is available, in which reading and writing can proceed concurrently.
By default, WAL is not enabled. To turn WAL on, refer to the SQLite documentation.
SQLite3 explicitly allows multiple connections:
(5) Can multiple applications or multiple instances of the same
application access a single database file at the same time?
Multiple processes can have the same database open at the same time.
Multiple processes can be doing a SELECT at the same time. But only
one process can be making changes to the database at any moment in
time, however.
For sharing connections, use SQLite3 shared cache:
Starting with version 3.3.0, SQLite includes a special "shared-cache"
mode (disabled by default)
In version 3.5.0, shared-cache mode was modified so that the same
cache can be shared across an entire process rather than just within a
single thread.
5.0 Enabling Shared-Cache Mode
Shared-cache mode is enabled on a per-process basis. Using the C
interface, the following API can be used to globally enable or disable
shared-cache mode:
int sqlite3_enable_shared_cache(int);
Each call sqlite3_enable_shared_cache() effects subsequent database
connections created using sqlite3_open(), sqlite3_open16(), or
sqlite3_open_v2(). Database connections that already exist are
unaffected. Each call to sqlite3_enable_shared_cache() overrides all
previous calls within the same process.
I had a similar code architecture as you. I used a single SQLite database which process A read from, while process B wrote to it concurrently based on events. (In python 3.10.2 using the most up to date sqlite3 version). Process B was continually updating the database, while process A was reading from it to check data. My issue was that it was working in debug mode, but not in "release" mode.
In order to solve my particular problem I used Write Ahead Logging, which is referenced in previous answers. After creating my database in Process B (write mode) I added the line:
cur.execute('PRAGMA journal_mode=wal') where cur is the cursor object created from establishing connection.
This set the journal to wal mode which allows for concurrent access for multiple reads (but only one write). In Process A, where I was reading the data, before connecting to the same database I included:
time.sleep(0.5)
Setting a sleep timer before a connection was made to the same database fixed my issue with it not working in "release" mode.
In my case: I did not have to manually set any checkpoints, locks, or transactions. Your use case might be different than mine however, so research is most likely required. Nevertheless, I hope this post helps and saves everyone some time!

create tables/rows in ram using sqlite?

I remember once i had temporary data used on a webpage. I used php and mysql to create a table that stored visitors ips and the port they requested. I didnt care how long they lasted because after 10mins or an hour the data would no longer be relevant. I cant remember how i did it but using sqlite instead...
How do i create a table for rows meant to be stored in ram only for a limited amount of time (a few minutes) using sqlite? Using C# .NET
You could use the following connection string: Data Source=:memory:;Version=3;New=True. It is important to note that a memory database exists as long as the connection remains open.

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