WIP ADAM fix to DOMFile - regressions introduced by '[optimise] Optim…

…ize start position of DOMPage findRecord()' and '[optimise] Switch 'Optimize start position of DOMPage findRecord()' to use ThreadLocal so there is an offset per-thread'
evolvedbinary · Dec 13, 2024 · 9b28b88 · 9b28b88
1 parent a8b21dd
commit 9b28b88
Showing 1 changed file with 64 additions and 26 deletions.
diff --git a/exist-core/src/main/java/org/exist/storage/dom/DOMFile.java b/exist-core/src/main/java/org/exist/storage/dom/DOMFile.java
@@ -3058,7 +3058,7 @@ protected final class DOMPage implements Cacheable {
         // set to true if the page has been removed from the cache
         boolean invalidated = false;
 
-        private final ThreadLocal<Integer> lastFound = ThreadLocal.withInitial(() -> 0);
+//        private final ThreadLocal<Integer> lastFound = ThreadLocal.withInitial(() -> 0);
 
         DOMPage() {
             this.page = createNewPage();
@@ -3105,33 +3105,10 @@ Page createNewPage() {
             }
         }
 
-        /**
-         * Optimize scanning for records in a page
-         * Based on the fact that we are looking for the same thing again,
-         * Or we are looking for something after the last thing.
-         *
-         * So, start the scan where we left off before.
-         *
-         * @param targetId the tuple id we are looking for in the page
-         *
-         * @return a record describing the tuple, if we found it, otherwise null
-         */
         RecordPos findRecord(final short targetId) {
-            final int startScan = lastFound.get();
-            RecordPos rec = findRecordInRange(targetId, startScan, pageHeader.getDataLength());
-            if (rec == null) {
-                rec = findRecordInRange(targetId, 0, startScan);
-            }
-            if (rec != null) {
-                // start from here again next time; step back over the tuple id
-                lastFound.set(rec.offset - LENGTH_TID);
-            }
-            return rec;
-        }
-
-        RecordPos findRecordInRange(final short targetId, final int from, final int to) {
+            final int dlen = pageHeader.getDataLength();
             RecordPos rec = null;
-            for (int pos = from; pos < to;) {
+            for (int pos = 0; pos < dlen;) {
                 final short tupleID = ByteConversion.byteToShort(data, pos);
                 pos += LENGTH_TID;
                 if (ItemId.matches(tupleID, targetId)) {
@@ -3162,6 +3139,67 @@ RecordPos findRecordInRange(final short targetId, final int from, final int to)
             return rec;
         }
 
+//        /**
+//         * Optimize scanning for records in a page
+//         * Based on the fact that we are looking for the same thing again,
+//         * Or we are looking for something after the last thing.
+//         *
+//         * So, start the scan where we left off before.
+//         *
+//         * @param targetId the tuple id we are looking for in the page
+//         *
+//         * @return a record describing the tuple, if we found it, otherwise null
+//         */
+//        RecordPos findRecord(final short targetId) {
+//            final int startScan = lastFound.get();
+//            try {
+//                RecordPos rec = findRecordInRange(targetId, startScan, pageHeader.getDataLength());
+//                if (rec == null) {
+//                    rec = findRecordInRange(targetId, 0, startScan);
+//                }
+//                if (rec != null) {
+//                    // start from here again next time; step back over the tuple id
+//                    lastFound.set(rec.offset - LENGTH_TID);
+//                }
+//                return rec;
+//            } catch (ArrayIndexOutOfBoundsException e) {
+//                throw e;
+//            }
+//        }
+//
+//        RecordPos findRecordInRange(final short targetId, final int from, final int to) {
+//            RecordPos rec = null;
+//            for (int pos = from; pos < to;) {
+//                final short tupleID = ByteConversion.byteToShort(data, pos);
+//                pos += LENGTH_TID;
+//                if (ItemId.matches(tupleID, targetId)) {
+//                    if (ItemId.isLink(tupleID)) {
+//                        rec = new RecordPos(pos, this, tupleID, true);
+//                    } else {
+//                        rec = new RecordPos(pos, this, tupleID);
+//                    }
+//                    break;
+//                } else if (ItemId.isLink(tupleID)) {
+//                    pos += LENGTH_FORWARD_LOCATION;
+//                } else {
+//                    final short vlen = ByteConversion.byteToShort(data, pos);
+//                    pos += LENGTH_DATA_LENGTH;
+//                    if (vlen < 0) {
+//                        LOG.error("page = {}; pos = {}; vlen = {}; tupleID = {}; target = {}", page.getPageNum(), pos, vlen, tupleID, targetId);
+//                    }
+//                    if (ItemId.isRelocated(tupleID)) {
+//                        pos += LENGTH_ORIGINAL_LOCATION + vlen;
+//                    } else {
+//                        pos += vlen;
+//                    }
+//                    if (vlen == OVERFLOW) {
+//                        pos += LENGTH_OVERFLOW_LOCATION;
+//                    }
+//                }
+//            }
+//            return rec;
+//        }
+
         @Override
         public long getKey() {
             return page.getPageNum();