STRING_AGG() Performance

Aaron Bertrand wants to know how the STRING_AGG() function performs:

We can see that our FORCESCAN hint really did make things worse – while we shifted the cost away from the clustered index seek, the sort was actually much worse, even though the estimated costs deemed them relatively equivalent. More importantly, we can see that STRING_AGG() does offer a performance benefit, whether or not the concatenated strings need to be ordered in a specific way. As with STRING_SPLIT(), which I looked at back in March, I am quite impressed that this function scales well prior to “v1.”

Given that the early releases tend to be “get the thing working” and later CTPs are around “make the thing faster,” it’s nice to see that STRING_AGG() is already ready for prime-time, and makes me wonder if they’ll make it even faster by RTM.

Related Posts

Validating SSIS Packages Using T-SQL

Annie Xu shows us how to validate SSIS packages in the SSISDB catalog using T-SQL: Recently, I need to do a data warehouse migration for a client. Since there might be some difference between the Dev environment source databases and Prod environment source databases. The migrated SSIS packages for building data warehouse might have some […]

Read More

APPROX_COUNT_DISTINCT

Niko Neugebauer is happy with a new function in SQL Server 2019: A rather interesting result takes place if we scale our database to 100GB TPCH and run the very same queries – the total elapsed time jumps to 50% difference (from 30%), the CPU execution time difference is kept at 50%, but the memory […]

Read More

Categories

December 2016
MTWTFSS
« Nov Jan »
 1234
567891011
12131415161718
19202122232425
262728293031