wy96f commented on a change in pull request #2645: ARTEMIS-2321 Paging scalability and GC improvement URL: https://github.com/apache/activemq-artemis/pull/2645#discussion_r279613543
########## File path: artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/cursor/impl/PageCursorProviderImpl.java ########## @@ -132,43 +156,88 @@ public PagedReference newReference(final PagePosition pos, @Override public PageCache getPageCache(final long pageId) { try { + if (pageId > pagingStore.getCurrentWritingPage()) { + return null; + } + boolean createPage = false; + CompletableFuture<PageCache> inProgressReadPage; PageCache cache; + Page page = null; synchronized (softCache) { - if (pageId > pagingStore.getCurrentWritingPage()) { + cache = softCache.get(pageId); + if (cache != null) { + return cache; + } + if (!pagingStore.checkPageFileExists((int) pageId)) { return null; } - - cache = softCache.get(pageId); - if (cache == null) { - if (!pagingStore.checkPageFileExists((int) pageId)) { - return null; - } - + inProgressReadPage = inProgressReadPages.get(pageId); + if (inProgressReadPage == null) { + final CompletableFuture<PageCache> readPage = new CompletableFuture<>(); cache = createPageCache(pageId); - // anyone reading from this cache will have to wait reading to finish first - // we also want only one thread reading this cache - logger.tracef("adding pageCache pageNr=%d into cursor = %s", pageId, this.pagingStore.getAddress()); - readPage((int) pageId, cache); - softCache.put(pageId, cache); + page = pagingStore.createPage((int) pageId); + createPage = true; + inProgressReadPage = readPage; + inProgressReadPages.put(pageId, readPage); } } + //We need to create a new criticalComponent each time, because + //each read page action can happen from a different thread + final CriticalComponent readPageActionComponent; + if (criticalAnalyzer == null) { + readPageActionComponent = null; + } else { + final SimpleString address = pagingStore.getAddress(); + readPageActionComponent = new CriticalComponentImpl(criticalAnalyzer, PAGE_CURSOR_PROVIDER_CRITICAL_PATHS) { Review comment: Do we need to cache the CriticalComponentImpl here to reduce memory footprint? ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services