Concurrent Qaurkus Rest Pagination - quarkus

Question

I am attempting to process all 261 pages of https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=1000 concurrently and asynchronously. Like most applications, I have to map the result details to another rest resource and post it to another system.
Initially, I did a simple #Blocking rest call in a while loop to make sure the Client was configured correctly. This took 48 minutes to return the 261 pages.
Next I converted to asynchronous reactive Multi paging via help from https://quarkus.io/blog/mutiny-pagination/
However as shown in the logs, this is processing in a single thread and actually hung on page 119.
The question is how to I change this to run concurrently based on a configurable amount of threads?
#GET
#Produces(MediaType.APPLICATION_JSON+";charset=iso-8859-1")
public GedResult findGedPage(Map<String, Integer> paramMap) {
return gedClient.findGedPage(paramMap);
}
public void pagination() {
log.info("STARTING GED EVENT PAGINATION");
long startTime = System.currentTimeMillis();
AtomicInteger totalPages = new AtomicInteger();
AtomicInteger totalDetails = new AtomicInteger();
Multi.createBy().repeating()
.supplier(
AtomicInteger::new,
page -> {
Map<String, Integer> paramMap = new HashMap<>(2);
paramMap.put("pagesize", pageSize);
paramMap.put("page", page.getAndIncrement());
return gedClient.findGedPage(paramMap);
})
.until(gedResult -> isBlank(gedResult.getNextPageUrl()))
.onItem()
.transform(Unchecked.function(result -> {
return mapToMyResource(result, totalPages, totalDetails);
}))
.subscribe()
.with(
this::sendDownstreamToPersist,
GedServiceException::new,
() -> log.info("onComplete:: Total Pages = " + totalPages.get() + " in " + (System.currentTimeMillis() - startTime) + " millis")
);
}
2022-08-15 14:40:36,528 INFO (pool-11-thread-1) [com.bar.ucdp.service.GedService.mapToMyResource()] NextPageUrl: https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=2000&page=116
2022-08-15 14:40:52,816 INFO (pool-11-thread-1) [com.bar.ucdp.service.GedService.mapToMyResource()] NextPageUrl: https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=2000&page=117
2022-08-15 14:41:05,997 INFO (pool-11-thread-1) [com.bar.ucdp.service.GedService.mapToMyResource()] NextPageUrl: https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=2000&page=118
2022-08-15 14:41:19,670 INFO (pool-11-thread-1) [com.bar.ucdp.service.GedService.mapToMyResource()] NextPageUrl: https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=2000&page=119
2022-08-15 14:41:33,894 INFO (pool-11-thread-1) [com.bar.ucdp.service.GedService.mapToMyResource()] NextPageUrl: https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=2000&page=120
2022-08-15 14:41:46,315 INFO (pool-11-thread-1) [com.bar.ucdp.service.GedService.mapToMyResource()] NextPageUrl: https://ucdpapi.pcr.uu.se/api/gedevents/21.1?pagesize=2000&page=121