best practice for multiple batch update

i've created a function to update a local database
i'm using data from API and update local table with update batch
from table no 1 (around 8000 rows and 15 columns)
i got memory usage
64976504
and memory peak usage
144559440


after 3 table, memory usage
112891344
memory peak usage
152110656


i've increase memory limit to 256
i update the 3 table in 1 function, and theres 4 more table

is there any best practice to do batch update?
batch update in the model, and the function call it 3 times for the 3 table

thank you

@t3ppei,

Have you verified that your batch queries are efficient? Have you done database maintenance to make sure that your database is at it's peak performance? How long does your batch update take to complete?