fix(cairo): 6.1 migration issues (#1494)

core/src/main/java/io/questdb/cairo/mig/Mig607.java

@@ -42,6 +42,8 @@ final class Mig607 {
 
 
         path.trimTo(plen).concat(META_FILE_NAME).$();
+        long metaFileSize;
+        long txFileSize;
         try (MemoryMARW metaMem = migrationContext.getRwMemory()) {
             metaMem.of(ff, path, ff.getPageSize(), ff.length(path), MemoryTag.NATIVE_DEFAULT);
             final int columnCount = metaMem.getInt(0);
@@ -143,7 +145,30 @@ final class Mig607 {
                         denseSymbolCount++;
                     }
                 }
+                txFileSize = txMem.getAppendOffset();
             }
+            metaFileSize = metaMem.getAppendOffset();
+        }
+
+        // This migration when written originally used implementation of MemoryMARW which truncated files to size on close
+        // MemoryMARW now truncate to page size. To test old migrations here we simulate the migration as it is originally released
+        // So trim TX and META files to their sizes
+        path.trimTo(plen).concat(META_FILE_NAME).$();
+        trimFile(ff, path, metaFileSize);
+
+        path.trimTo(plen).concat(TXN_FILE_NAME).$();
+        trimFile(ff, path, txFileSize);
+    }
+
+    private static void trimFile(FilesFacade ff, Path path, long size) {
+        long fd = TableUtils.openFileRWOrFail(ff, path);
+        if (!ff.truncate(fd, size)) {
+            // This should never happens on migration but better to be on safe side anyway
+            throw CairoException.instance(ff.errno()).put("Cannot trim to size [file=").put(path).put(']');
+        }
+        if (!ff.close(fd)) {
+            // This should never happens on migration but better to be on safe side anyway
+            throw CairoException.instance(ff.errno()).put("Cannot close [file=").put(path).put(']');
         }
     }
 

core/src/main/java/io/questdb/cairo/mig/Mig608.java

@@ -85,7 +85,7 @@ final class Mig608 {
             o = offset + thatMetaColumnDataSize * (columnCount - 1);
             long o2 = offset + thisMetaColumnDataSize * (columnCount - 1);
             final Rnd rnd = SharedRandom.getRandom(migrationContext.getConfiguration());
-            while (o > offset) {
+            while (o >= offset) {
                 rwMem.putInt(o2, rwMem.getInt(o)); // type
                 rwMem.putLong(o2 + 4, rwMem.getInt(o + 4)); // flags
                 rwMem.putInt(o2 + 12, rwMem.getInt(o + 12)); // index block capacity
@@ -93,6 +93,7 @@ final class Mig608 {
                 o -= thatMetaColumnDataSize;
                 o2 -= thisMetaColumnDataSize;
             }
+            rwMem.jumpTo(newNameOffset + nameSegmentLen);
         }
 
         // update _txn file
@@ -119,6 +120,7 @@ final class Mig608 {
             long thatSize = thatTxOffsetMapWriterCount + 4 + symbolCount * 8L + 4L + partitionTableSize;
             long thisSize = thisTxOffsetMapWriterCount + 4 + symbolCount * 8L + 4L + partitionTableSize;
             txMem.extend(thisSize);
+            txMem.jumpTo(thisSize);
             Vect.memmove(txMem.addressOf(thisTxOffsetMapWriterCount), txMem.addressOf(thatTxOffsetMapWriterCount), thatSize - thatTxOffsetMapWriterCount);
 
             // zero out reserved area