Is it OK to globally set the mybatis executor mode to BATCH? - mybatis

Question

I am currently developing a Spring Boot app, which uses mybatis for its persistence layer. I want to optimize the batch insertion of entities in the following scenario:
// flightSerieMapper and legMapper are used to create a series of flights.
// legMapper needs to use batch insertion.
#Transactional
public FlightSerie add(FlightSerie flightSerie) {
Integer flightSerieId = flightSeriesSequenceGenerator.getNext();
flightSerie.setFlightSerieId(flightSerieId);
flightSerieMapper.create(flightSerie);
// create legs in batch mode
for (Leg leg : flightSerie.getFlightLegs()) {
Integer flightLegId = flightLegsSequenceGenerator.getNext();
leg.setLegId(flightLegId);
legMapper.create(leg);
}
return flightSerie;
}
mybatis is configured as follows in application.properties:
# this can be externalized if necessary
mybatis.config-location=classpath:mybatis-config.xml
mybatis.executor-type=BATCH
This means that mybatis will execute all statements in batch mode by default, including single insert/update/delete statements. Is this OK? Are there any issues I should be aware of?
Another approach would be to use a dedicated SQLSession specifically for the LegMapper. Which approach is the best (dedicated SQLSession vs global setting in application.properties)?
Note: I have seen other examples where "batch inserts" are created using a <foreach/> loop directly in the mybatis xml mapper file. I don't want to use this approach because it does not actually provide a batch insert.

Answer 1

As #Ian Lim said, make sure you annotate mapper methods with inserts and updates with #Flush annotation if you globally set executor type to BATCH.
Another approach would be to use a dedicated SQLSession specifically
for the LegMapper. Which approach is the best (dedicated SQLSession vs
global setting in application.properties)?
Keep in mind that if you are using different SQL sessions for different mappers there will be different transactions for each SQL session. If a service or service method annotated with #Transactional uses several mappers that use different SQL sessions it will allocate different SQL transactions. So it's impossible to do atomic data operation that involves mappers with different SQL sessions.