diff options
| author | Brian S. O'Neill <bronee@gmail.com> | 2006-10-31 18:04:54 +0000 |
|---|---|---|
| committer | Brian S. O'Neill <bronee@gmail.com> | 2006-10-31 18:04:54 +0000 |
| commit | 332cccc96e2a9014cbc1d614fedc35048315b53a (patch) | |
| tree | 2c8d9f8ede7f1503cc023d0b662e7cf575376aa3 /src/main/java/com/amazon/carbonado/layout | |
| parent | e009e8ea98d8c9c15e0a90a5085ac435093cb9ed (diff) | |
Cope with errors during resync.
Diffstat (limited to 'src/main/java/com/amazon/carbonado/layout')
| -rw-r--r-- | src/main/java/com/amazon/carbonado/layout/LayoutFactory.java | 150 |
1 files changed, 91 insertions, 59 deletions
diff --git a/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java b/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java index 89e139d..6deb3ee 100644 --- a/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java +++ b/src/main/java/com/amazon/carbonado/layout/LayoutFactory.java @@ -33,6 +33,9 @@ import com.amazon.carbonado.RepositoryException; import com.amazon.carbonado.Storable;
import com.amazon.carbonado.Storage;
import com.amazon.carbonado.Transaction;
+import com.amazon.carbonado.UniqueConstraintException;
+
+import com.amazon.carbonado.capability.ResyncCapability;
import com.amazon.carbonado.info.StorableInfo;
import com.amazon.carbonado.info.StorableIntrospector;
@@ -86,73 +89,102 @@ public class LayoutFactory implements LayoutCapability { StorableInfo<?> info = StorableIntrospector.examine(type);
- Transaction txn = mRepository.enterTopTransaction(IsolationLevel.READ_COMMITTED);
- txn.setForUpdate(true);
- try {
- // If type represents a new generation, then a new layout needs to
- // be inserted.
- Layout newLayout = null;
-
- for (int i=0; i<HASH_MULTIPLIERS.length; i++) {
- // Generate an identifier which has a high likelyhood of being unique.
- long layoutID = mixInHash(0L, info, HASH_MULTIPLIERS[i]);
-
- // Initially use for comparison purposes.
- newLayout = new Layout(this, info, layoutID);
+ Layout layout;
+ ResyncCapability resyncCap = null;
- StoredLayout storedLayout = mLayoutStorage.prepare();
- storedLayout.setLayoutID(layoutID);
-
- if (!storedLayout.tryLoad()) {
- // Not found, so break out and insert.
- break;
- }
-
- Layout knownLayout = new Layout(this, storedLayout);
- if (knownLayout.equalLayouts(newLayout)) {
- // Type does not represent a new generation. Return
- // existing layout.
- return knownLayout;
+ // Try to insert metadata up to three times.
+ loadLayout: for (int retryCount = 3;;) {
+ try {
+ Transaction txn = mRepository.enterTopTransaction(IsolationLevel.READ_COMMITTED);
+ txn.setForUpdate(true);
+ try {
+ // If type represents a new generation, then a new layout needs to
+ // be inserted.
+ Layout newLayout = null;
+
+ for (int i=0; i<HASH_MULTIPLIERS.length; i++) {
+ // Generate an identifier which has a high likelyhood of being unique.
+ long layoutID = mixInHash(0L, info, HASH_MULTIPLIERS[i]);
+
+ // Initially use for comparison purposes.
+ newLayout = new Layout(this, info, layoutID);
+
+ StoredLayout storedLayout = mLayoutStorage.prepare();
+ storedLayout.setLayoutID(layoutID);
+
+ if (!storedLayout.tryLoad()) {
+ // Not found, so break out and insert.
+ break;
+ }
+
+ Layout knownLayout = new Layout(this, storedLayout);
+ if (knownLayout.equalLayouts(newLayout)) {
+ // Type does not represent a new generation. Return
+ // existing layout.
+ layout = knownLayout;
+ break loadLayout;
+ }
+
+ // If this point is reached, then there was a hash collision in
+ // the generated layout ID. This should be extremely rare.
+ // Rehash and try again.
+
+ if (i >= HASH_MULTIPLIERS.length - 1) {
+ // No more rehashes to attempt. This should be extremely,
+ // extremely rare, unless there is a bug somewhere.
+ throw new FetchException
+ ("Unable to generate unique layout identifier");
+ }
+ }
+
+ // If this point is reached, then type represents a new
+ // generation. Calculate next generation value and insert.
+
+ assert(newLayout != null);
+ int generation = 0;
+
+ Cursor<StoredLayout> cursor = mLayoutStorage
+ .query("storableTypeName = ?")
+ .with(info.getStorableType().getName())
+ .orderBy("-generation")
+ .fetch();
+
+ try {
+ if (cursor.hasNext()) {
+ generation = cursor.next().getGeneration() + 1;
+ }
+ } finally {
+ cursor.close();
+ }
+
+ newLayout.insert(generation);
+ layout = newLayout;
+
+ txn.commit();
+ } finally {
+ txn.exit();
}
- // If this point is reached, then there was a hash collision in
- // the generated layout ID. This should be extremely rare.
- // Rehash and try again.
-
- if (i >= HASH_MULTIPLIERS.length - 1) {
- // No more rehashes to attempt. This should be extremely,
- // extremely rare, unless there is a bug somewhere.
- throw new FetchException("Unable to generate unique layout identifier");
- }
+ break;
+ } catch (UniqueConstraintException e) {
+ // This might be caused by a transient replication error. Retry
+ // a few times before throwing exception. Wait up to a second
+ // before each retry.
+ retryCount = e.backoff(e, retryCount, 1000);
+ resyncCap = mRepository.getCapability(ResyncCapability.class);
}
+ }
- // If this point is reached, then type represents a new
- // generation. Calculate next generation value and insert.
-
- assert(newLayout != null);
- int generation = 0;
-
- Cursor<StoredLayout> cursor = mLayoutStorage
- .query("storableTypeName = ?")
- .with(info.getStorableType().getName())
- .orderBy("-generation")
- .fetch();
-
+ if (resyncCap != null) {
+ // Make sure that all layout records are sync'd.
try {
- if (cursor.hasNext()) {
- generation = cursor.next().getGeneration() + 1;
- }
- } finally {
- cursor.close();
+ resyncCap.resync(StoredLayoutProperty.class, 1.0, null);
+ } catch (RepositoryException e) {
+ throw e.toPersistException();
}
-
- newLayout.insert(generation);
- txn.commit();
-
- return newLayout;
- } finally {
- txn.exit();
}
+
+ return layout;
}
/**
|