Examples with Pin org.neo4j.io.pagecache.tracing.recording.RecordingPageCursorTracer.Pin used on opensource projects

Example 1 with Pin

use of org.neo4j.io.pagecache.tracing.recording.RecordingPageCursorTracer.Pin in project neo4j by neo4j.

the class CommonAbstractStoreTest method recordCursorPinsEachPageItReads.

@Test
public void recordCursorPinsEachPageItReads() throws Exception {
    File storeFile = dir.file("a");
    RecordingPageCacheTracer tracer = new RecordingPageCacheTracer();
    RecordingPageCursorTracer pageCursorTracer = new RecordingPageCursorTracer(Pin.class);
    PageCacheRule.PageCacheConfig pageCacheConfig = config().withTracer(tracer).withCursorTracerSupplier(pageCursorTracerSupplier(pageCursorTracer));
    PageCache pageCache = pageCacheRule.getPageCache(fileSystemRule.get(), pageCacheConfig, Config.empty());
    try (NodeStore store = new NodeStore(storeFile, Config.empty(), new DefaultIdGeneratorFactory(fileSystemRule.get()), pageCache, NullLogProvider.getInstance(), null, Standard.LATEST_RECORD_FORMATS)) {
        store.initialise(true);
        assertNull(tracer.tryObserve(Event.class));
        long nodeId1 = insertNodeRecordAndObservePinEvent(pageCursorTracer, store);
        long nodeId2 = insertNodeRecordAndObservePinEvent(pageCursorTracer, store);
        try (RecordCursor<NodeRecord> cursor = store.newRecordCursor(store.newRecord())) {
            cursor.acquire(0, RecordLoad.NORMAL);
            assertTrue(cursor.next(nodeId1));
            assertTrue(cursor.next(nodeId2));
        }
        // Because both nodes hit the same page, the code will only pin the page once and thus only emit one pin
        // event. This pin event will not be observable until after we have closed the cursor. We could
        // alternatively have chosen nodeId2 to be on a different page than nodeId1. In that case, the pin event
        // for nodeId1 would have been visible after our call to cursor.next( nodeId2 ).
        assertNotNull(pageCursorTracer.tryObserve(Pin.class));
        assertNull(pageCursorTracer.tryObserve(Event.class));
    }
}