I recently ran into a strange issue with the 50,000 row query limit that had me puzzled due to the belief that the 50,000 row query limit applied only per-call.
This realization occurred while writing a LWC where the
.js file calls apex methods to gather data. Specifically, in this instance, I was creating a custom table that displays some aggregated data and only loads and displays 5 rows at time. Users can page through the table to load and display 5 more items.
Whenever I am loading a table page, the JS side makes 5 separate calls (one for each row) to the same APEX method to gather all the aggregated data. I actually use a Promise to send off all 5 calls at one time.
Inside of this reused APEX method is a few queries that get about
2500 rows combined MAX.
This apex method does not query over 2500 rows per-call in any case.
When JS uses a promise to send off 5 of these calls at once, I have no problem. However, I also allow users to download the entire table into a csv. When they hit this button, JS uses the same APEX method to load the data, but this part requires JS to put more than 5 calls to the same method in the Promise that gathers all the data. If the table is 10 pages, it ends up putting 50 calls to the same APEX method in the same promise. This is when I get the
50,000 query limit reached error.
This has me confused because I thought that
a single call to an APEX method can't query over 50,000 rows... After playing around a little, I noticed that the error would occur once I tried to load more than 20 rows. 19 rows worked fine because 19 * 2500 < 50,000. But 21 rows errored because 21* 2500 > 50,000.
Therefore, I believe that the 50,000 query limit isn't calculated per APEX Method call, but rather calculated on the total number of simultaneous calls to the same APEX method.