Yanked out support for fast skipping of JDBC results. JDBC drivers leak memory when this option is used.

2 files changed, 7 insertions, 62 deletions

diff --git a/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCCursor.java b/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCCursor.java
index 28b73c7..985232c 100644
--- a/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCCursor.java
+++ b/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCCursor.java
@@ -37,27 +37,22 @@ class JDBCCursor<S extends Storable> extends AbstractCursor<S> {
     private final JDBCStorage<S> mStorage;

     private final Connection mConnection;

     private final PreparedStatement mStatement;

-    private final boolean mScrollInsensitiveReadOnly;

 

     private ResultSet mResultSet;

     private boolean mHasNext;

 

     /**

-     * @param scrollInsensitiveReadOnly when true, statement is

-     * TYPE_SCROLL_INSENSITIVE and CONCUR_READ_ONLY.

      * @throws SQLException from executeQuery on statement. Caller must clean

      * up when this happens by closing statement and connection.

      */

     JDBCCursor(JDBCStorage<S> storage,

                Connection con,

-               PreparedStatement statement,

-               boolean scrollInsensitiveReadOnly)

+               PreparedStatement statement)

         throws SQLException

     {

         mStorage = storage;

         mConnection = con;

         mStatement = statement;

-        mScrollInsensitiveReadOnly = scrollInsensitiveReadOnly;

         mResultSet = statement.executeQuery();

     }

 

@@ -127,48 +122,11 @@ class JDBCCursor<S extends Storable> extends AbstractCursor<S> {
 

         int actual = 0;

 

-        if (amount > 1 && mScrollInsensitiveReadOnly) {

-            // Skip a relative amount, which is preferred.

+        while (amount > 0) {

             if (hasNext()) {

-                ResultSet rs = mResultSet;

-                try {

-                    int rowStart = rs.getRow();

-                    mHasNext = rs.relative(amount);

-                    int rowEnd = rs.getRow();

-                    if (rowEnd == 0) {

-                        // Skipped past the end. Move back to find the last row number.

-                        if (rs.previous() && (rowEnd = rs.getRow()) != 0) {

-                            rowEnd++;

-                        } else if (rs.last() && (rowEnd = rs.getRow()) != 0) {

-                            rowEnd++;

-                        } else {

-                            // No clue how many were skipped. It's at least one.

-                            rowEnd = rowStart + 1;

-                        }

-                        // Make sure ResultSet is closed below.

-                        mHasNext = false;

-                    }

-                    actual += rowEnd - rowStart;

-                } catch (SQLException e) {

-                    try {

-                        close();

-                    } catch (FetchException e2) {

-                        // Don't care.

-                    }

-                    throw mStorage.getJDBCRepository().toFetchException(e);

-                }

-                if (!mHasNext) {

-                    close();

-                }

-            }

-        } else {

-            // Call next a bunch, which is likely slower than relative skipping.

-            while (amount > 0) {

-                if (hasNext()) {

-                    actual++;

-                    amount--;

-                    mHasNext = false;

-                }

+                actual++;

+                amount--;

+                mHasNext = false;

             }

         }

 

diff --git a/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCStorage.java b/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCStorage.java
index 384f1bc..2421be7 100644
--- a/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCStorage.java
+++ b/src/main/java/com/amazon/carbonado/repo/jdbc/JDBCStorage.java
@@ -488,24 +488,11 @@ class JDBCStorage<S extends Storable> extends StandardQueryFactory<S>
             boolean forUpdate = mRepository.localTxnManager().isForUpdate();

             Connection con = mRepository.getConnection();

             try {

-                boolean scrollInsensitiveReadOnly =

-                    mRepository.supportsScrollInsensitiveReadOnly();

-

-                PreparedStatement ps;

-

-                if (scrollInsensitiveReadOnly) {

-                    // Can support fast skipping.

-                    ps = con.prepareStatement

-                        (prepareSelect(values, forUpdate),

-                         ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);

-                } else {

-                    // Can't support fast skipping.

-                    ps = con.prepareStatement(prepareSelect(values, forUpdate));

-                }

+                PreparedStatement ps = con.prepareStatement(prepareSelect(values, forUpdate));

 

                 try {

                     setParameters(ps, values);

-                    return new JDBCCursor<S>(JDBCStorage.this, con, ps, scrollInsensitiveReadOnly);

+                    return new JDBCCursor<S>(JDBCStorage.this, con, ps);

                 } catch (Exception e) {

                     // in case of exception, close statement

                     try {