Hello,
we were are using “blend Data” two combine two tables.
This worked fine and fast for the last years, until last week. It is extremely slow now and takes half a minute to react and not usable anymore.
The issue is that the first table needs to filter the 2nd table with the merge left condition.
A very long table A contains all single items with a an attribute column.
A short table B contains also this attribute column and some meta information also encoded images which are rendered with Community visualization. Thus table B is short, but 200 MB large.
The left join table A to B is done by the attribute column. More in detail the max and min value of the attribute column is compared and if equal returned, otherwise a the value zero is returned by the calculated field of table A. Thus only one single value is used for the join and one row of table B is returned by BigQuery.
It looks like some backend joining operation was changed in Data Studio in the last weeks:
Thanks a lot! Best wishes