How SQL Server 2014 impacts Red Gate’s SQL Compare
- by Michelle Taylor
SQL Compare 10.7 successfully connects to SQL Server 2014, but it doesn’t yet cover the SQL Server 2014 features which would require us to make major changes to SQL Compare to support. In this post I’m going to talk about the SQL Server 2014 features we’ve already begun supporting, and which ones we’re working on for the next release of SQL Compare (v11).
From SQL Compare’s perspective, the new memory-optimized table functionality (some might know it as ‘Hekaton’) has been the most important change. It can’t be described as its own object type, but the new functionality is split across two existing object types (three if you count indexes), as it also comes with native stored procedures and inline indexes.
Along with connectivity support, the SQL Compare team has already implemented the first part of the puzzle – inline specification of indexes. These are essential for memory-optimized tables because it’s not possible to alter the memory optimized table’s structure, and so indexes can’t be added after the fact without dropping the table. Books Online shows this in more detail in the table_index and column_index clauses of http://msdn.microsoft.com/en-us/library/ms174979(v=sql.120).aspx.
SQL Compare 10.7 currently supports reading the new inline index specification from script folders and source control repositories, and will write out inline indexes where it’s necessary to do so (i.e. in UDDTs or when attempting to write projects compatible with the SSDT database project format). However, memory-optimized tables themselves are not yet supported in 10.7. The team is actively working on making them available in the v11 release with full support later in the year, and in a beta version before that. Fortunately, SQL Compare already has some ways of handling tables that have to be dropped and created rather than altered, which are being adapted to handle this new kind of table.
Because it’s one of the largest new database engine features, there’s an equally large Books Online section on memory-optimized tables, but for us the most important parts of the documentation are the normal table features that are changed or unsupported and the new syntax found in the T-SQL reference pages.
We are treating SQL Compare’s support of Natively Compiled Stored Procedures as a separate unit of work, which will be available in a subsequent beta and also feed into the v11 release. This new type of stored procedure is designed to work with memory-optimized tables to maintain the performance improvements gained by them – but you can still also access memory-optimized tables from normal stored procedures and ad-hoc queries. To us, they’re essentially a limited-syntax stored procedure with a few extra options in the create statement, embodied in the updated CREATE PROCEDURE documentation and with the detailed limitations.
They should be easier to handle than memory-optimized tables simply because the handling of stored procedures is less sensitive to dropping the object than the handling of tables. However, both share an incompatibility with DDL triggers and Event Notifications which mean we’ll need to temporarily disable these during the specific deployment operations that involve them – don’t worry, we’ll supply a warning if this is the case so that you can check your auditing arrangements can handle the situation.
There are also a handful of other improvements in SQL Server 2014 which affect SQL Compare and SQL Data Compare that are not connected to memory optimized tables. The largest of these are the improvements to columnstore indexes, with the capability to create clustered columnstore indexes and update columnstore tables through them – for more detail, take a look at the new syntax reference.
There’s also a new index option for better compression of columnstores (COLUMNSTORE_ARCHIVE) and a new statistics option for incremental per-partition statistics, plus the 90 compatibility level is being retired.
We’re planning to finish up these small clean-up features last, and be ready to release SQL Compare 11 with full SQL 2014 support early in Q3 this year.
For a more thorough overview of what’s new in SQL Server 2014, Books Online’s What’s New section is a good place to start (although almost all the changes in this version are in the Database Engine).
