I have a requirement to implement CDC for 50+ tables to implement incremental data changes warehouse/reporting rather than exporting the whole table data. The largest table is having more than half a billion records.
The warehouse use a daily copy of OLTP db (daily DB refresh). How can I accomplish this. Is there a downside in implementing CDC just for the sake of taking incremental changes on the tables?
Is there any performance impact if we enable CDC on OLTP db?
Can we make use of the CDC tables on the environment we do daily db refresh so that the queries don't hit OLTP database?
What is the best way to implement CDC to take incremental changes for reporting.
I have a matrix table. These status can be changed by the user and I want to capture each change in database with out updating the earlier status
Pending Activated In PROGRESS Submitted Completed
Pending can be changed to submitted or completed. For one form there can be different status at different time. And each status must be saved in the database table. How can I design a table...
When using Change Data Capture on SQL Server 2012 I have researched that you cannot truncate data in a table. Is this also true if one wanted to delete data from the table? Getting a little confused about what DDL statements can be ran against a table with CDC enabled. Does CDC have to be disabled before performing certain DDL statements against a table?
I would like to safeguard the truncation and dropping of certain tables within the dbo schema. Wondering if I could do this with one fail swoop with CDC enabled on those tables. The other option would be to use a DDL trigger to prevent certain DDL statements to be performed.
Hi All, I am now working on the design phase of my project, we are looking to implement Change Data Capture (CDC) but i need some help if you guys has implemented before using the SSIS 2005 componets. I am trying to use the Following:
Source---------Derived Column---------Lookup---------------Conditional Split (to split New records and Updated Records)-----------Destination. Respectively. Lets make it clear, my source holds (Old records and newly added or Updated records), the Derived Column is to Derive new columns called Insert_Date and Update_Date. The Lookup i am Using is to look the Fact_Table(the Old Records) as Reference, and then based on this lookup i will split the records on timely based using the Conditional Split. My question is 1. Am i using the right components? 2. what consideration should i have to see to make it true (some Logics on the conditional split)? 3. Any script which helps in this strategy? 4. If you have a better idea please try to help me, i need you help badly.
Or can it record before and after column changes based on the LSN only?
An extract from a file based legacy accounting system is performed every night. The system does not have a primary key because transactions are managed through program code. (the more things change...). The extract is copied to text in Unix and FTP'd to Windows, where the file is loaded into SQL Server by kill & fill. Because of the expense of modifying the source system, there is enormous inertia/resistance to injecting a primary key at the source, so kill & fill it stays.
In reading about Change Data Capture, it seemed to me that column level insert update and delete are stored in tables that remember the before and after content of each column tracked. In my reading I have seen many references to the LSN to decide when and what to record as changed, but I have not seen any refereference to the necessity of a primary key for Change Data Capture to work. This is in contrast to replication, where the requirement for the existence of a primary key is made plain.
Is it possible to use Change Data Capture against a table without a primary key? How to use it to change the extract from kill and fill to incremental.
How you would calculate the average read/write latency experienced by a SQL Server instance during a specific time window in order to monitor this for multiple instances. From this MSDN blog, I know that you have to take multiple samples and do some calculations to get the correct latency.
[URL] ...
However, the SQLServer:Resource Pool Stats object tracks these numbers per resource pool and we want to get one number for the whole server. Since there can be a different base value for each resource pool, you can't simply sum the numerator values together. Here's some sample data from a server that illustrates the problem.
object_name counter_name instance_name cntr_value cntr_type SQLServer:Resource Pool Stats Avg Disk Read IO (ms) default 307318919 1073874176 SQLServer:Resource Pool Stats Avg Disk Read IO (ms) Base default 25546724 1073939712 SQLServer:Resource Pool Stats Avg Disk Read IO (ms) internal 2045730 1073874176 SQLServer:Resource Pool Stats Avg Disk Read IO (ms) Base internal 208270 1073939712
I'm thinking I would need to do some sort of weighted average, but I'm not sure if that will result in the correct value. Here's the formula I am thinking about using currently before doing the calculation over time
Again, looking for the best way to do this with SSIS.
I have a source table and I'd like to load it to a database daily, capturing what changed.
This is not a dimentional table but a fact table.
So, what I;d need to do for each record is to see if the record already exists (using business key) and if it does - compare some of the data fields and of there are changes - register it somehow and if not changes ignore.
Right now, the only two ways I see to do it with SSIS:
- Use Slowly Chaging Dimentions transformation
- Use Lookup and customize SQL, adding something like: WHERE key = ? and (field1 <> ? or field2 <> ?...)
I am using SQL Server 2012 and to me a part of data captured by CDC is not making sense.
I have a table called 'Schema.Table1', and I enabled CDC on it by running 'sys.sp_cdc_enable_table'. I see that a table called 'cdc.Schema_Table1_CT' got created which now gets an entry when ever I Insert, Update or delete a record in the original table.
Till this point every thing works fine.
My original Table has a NOT NULL INT column called 'AuditTrackerUserID' with a default value of 1996. My application does not provides a value for this column, but because the column itself has a default value, records get inserted without error.
When I try to execute the following Query I see multiple records with __$operation of 3 and 1.
SELECT * from cdc.Schema_Table1_CT where AuditTrackerUserID IS NULL
My expectation is that I should not ever see any record returned by this query because AuditTrackerUserID is a not null column, but I do.
We have enabled Change Data Capture for auditing our table changes in SQL Server 2008. There is a request to NULL out a few columns (for all rows) in a couple CDC tables, due to compliance with a certification. Is there a compelling reason not to modify these tables and to leave the audit trail as-is?
SQL Server 2008R2: Enabling Change Data Capture on a replicated database or its tables will have any performance impact on existing transactional replication.Is it possible to use both of them con temporarily.
Each one of the tables listed below has a “CreateDateTime” and “UpdateDateTime” fields, I need to get yesterday changes, I can get any record where either CreateDateTime or UpdateDateTime is greater than midnight yesterday butI need to watch dates on all of the tables so I need to do atleast 10 date checks.
If any table shows an updated or created record, I need to gather ALL of the information for that customer. So, if my name didn’t change (SCUS table), but my email does (SEML table), I have to pull out both the SCUS and SEML tables (and the others, of course). So It may not be simple WHERE clause, How can I achieve this:
I have located a bug in the functions cdc.fn_cdc_get_net_changes_<capture_instance> generated when you enable cdc on a table. This bug can be triggered if 2 rows are created in the _CT table having the same values for the __$start_lsn, __$seqval and the table's key column(s). From research on the internet I have found such rows can be created by a "deferred update": a single update statement in which a column that is part of a unique constraint is updated.
In order to report the bug with Microsoft I need to create a complete series of steps-to-reproduce. But even though the situation happens several times a day in our production environment, I have not yet been able to reproduce it in my test environment.I need a single update statement (plus maybe some steps in advance) that make that the log reader inserts 2 rows into the _CT table, one with __$operation = 1 (delete) and another with __$operation = 2 (insert) as opposed to the single row with __$operation = 4 that it inserts for a normal update. Below is the script I have so far to create a fresh database, enable cdc, create a test table, insert some data and update this data.
I would have liked the last update statement to be handled as a "deferred update". However in all of my tests the log reader just simply inserts a single row into the cdc.dbo_NETTEST_CT table.how to reproduce the situation where I get the 2 rows with __$operation 1 and 2 from a single update statement instead of the single row with __$operation = 4.
I have a task where I'm dealing with Employee information. I load this data on a daily basis where I capture Name,Is_Active,Address information of the employee and I do truncate and load operation. Now I have a task to have a additional column called 'Statuschanged_dt' and have to capture the date when Is_Active changed from 'Yes' to 'No'. I know this can done in multiple ways like destination lookup, SCD and also CDC.
I am asking about a virtual IP for SQL Server, is there a way we can assign a different IP to SQL Server other than the server's(host) IP address? like the same what we do in a clustered env.
I am task with identifying the source database name, id, and server name for each staging table that I create. I need to add this to a derived column on all staging tables created from merging same tables on different servers together.
When doing a Merge Join, there is no way to identify the source of data so I would like to see if data came from one database more than the other servers or if their are duplicates across servers.
The thing that bugs me about SSIS Data Flow task is there is no way to do an easy Execute SQL Task after I select my ADO.NET Source to get this information because my connection string is dynamic and there is no way of know which data source is being picked up at runtime.
For Example I have Products table on Server 1 and 2:
Server 2 has more Products and would like to join the two together to create a staging table.
We have several read-only nodes in our AlwaysOn cluster, which are set to use Synchronous-commit mode, which ensures that the logs are updated on the read-only nodes before any update statements complete. Even with this option, if we query a read-only node before the logs have been processed, we can read old data. I would like to know a strategy to ensure that a read-only query will definitely return up to date information. I had an idea that if I just used a different transaction type, like Serializable, that it might block the read-only query from actually getting the data until after the log file was processed, but I have not tried it, yet.
I would like to move more queries to the read-only nodes, in an effort to offload CPU utilization from the primary node.
Is there anyway to check if server is having disk latency or IO issues?Found below in SQL error log
Date10/1/2014 8:28:58 AM LogSQL Server (Current - 10/1/2014 12:00:00 AM)
Sourcespid10s
Message SQL Server has encountered 8500 occurrence(s) of I/O requests taking longer than 15 seconds to complete on file [D:Fin.mdf] in database [Fin] (5). The OS file handle is 0x0000000000001368. The offset of the latest long I/O is: 0x0001104a7da000
Hi Everybody, Can anybody tell me how to get the number of commands delivered per minute in case of Merge Replication with Publisher and subscribers. This way, we can be sure that even if there is a latency (due to high volume transaction processing), replication is in good shape and things will catch up soon. Also if there are any other similar measures which can be monitored to make sure that replication is going on fine, it would be great
Please let me know If anyone has got information on same.