chibenwa commented on code in PR #2514: URL: https://github.com/apache/james-project/pull/2514#discussion_r1858151717
########## mailbox/postgres/src/main/java/org/apache/james/mailbox/postgres/mail/dao/PostgresMailboxMessageDAO.java: ########## @@ -273,31 +270,55 @@ public Mono<Pair<Integer, Integer>> countTotalAndUnseenMessagesByMailboxId(Postg } public Flux<Pair<SimpleMailboxMessage.Builder, Record>> findMessagesByMailboxId(PostgresMailboxId mailboxId, Limit limit, MessageMapper.FetchType fetchType) { - PostgresMailboxMessageFetchStrategy fetchStrategy = FETCH_TYPE_TO_FETCH_STRATEGY.apply(fetchType); - Function<DSLContext, SelectSeekStep1<Record, Long>> queryWithoutLimit = dslContext -> dslContext.select(fetchStrategy.fetchFields()) - .from(MESSAGES_JOIN_MAILBOX_MESSAGES_CONDITION_STEP) - .where(MAILBOX_ID.eq(mailboxId.asUuid())) - .orderBy(DEFAULT_SORT_ORDER_BY); + if (limit.isUnlimited()) { + return Flux.range(0, OFFSET_UNLIMITED) + .concatMap(offsetIndex -> findMessagesByMailboxIdBatch(mailboxId, fetchType, offsetIndex * queryBatchSize, queryBatchSize)) + .takeUntil(List::isEmpty) + .flatMapIterable(Function.identity()); + } else { + return findMessagesByMailboxIdBatch(mailboxId, fetchType, 0, limit.getLimit().get()) + .flatMapIterable(Function.identity()); + } + } - return postgresExecutor.executeRows(dslContext -> limit.getLimit() - .map(limitValue -> Flux.from(queryWithoutLimit.andThen(step -> step.limit(limitValue)).apply(dslContext))) - .orElse(Flux.from(queryWithoutLimit.apply(dslContext)))) - .map(record -> Pair.of(fetchStrategy.toMessageBuilder().apply(record), record)); + private Mono<List<Pair<SimpleMailboxMessage.Builder, Record>>> findMessagesByMailboxIdBatch(PostgresMailboxId mailboxId, MessageMapper.FetchType fetchType, int offset, int batchSize) { + PostgresMailboxMessageFetchStrategy fetchStrategy = FETCH_TYPE_TO_FETCH_STRATEGY.apply(fetchType); + return postgresExecutor.executeRows(dslContext -> Flux.from(dslContext.select(fetchStrategy.fetchFields()) + .from(MESSAGES_JOIN_MAILBOX_MESSAGES_CONDITION_STEP) + .where(MAILBOX_ID.eq(mailboxId.asUuid())) + .orderBy(DEFAULT_SORT_ORDER_BY) + .limit(batchSize) + .offset(offset))) Review Comment: Actually we would be WAY more resilient not using an offset. We SHALL reuse the highest UID from the previous batch and resume from it. This would make us reslient to deletion in already paged items. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@james.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: notifications-unsubscr...@james.apache.org For additional commands, e-mail: notifications-h...@james.apache.org