Merge pull request #327 from softwareconstruction240/fix-memory-overf…

…low-all-latest-submissions

filter with index before sorting

src/main/java/edu/byu/cs/dataAccess/sql/SubmissionSqlDao.java

@@ -9,15 +9,12 @@
 import edu.byu.cs.model.Phase;
 import edu.byu.cs.model.Submission;
 
-import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Timestamp;
 import java.time.Instant;
 import java.util.*;
 
-import static java.sql.Types.NULL;
-
 public class SubmissionSqlDao implements SubmissionDao {
     private static final ColumnDefinition[] COLUMN_DEFINITIONS = {
             new ColumnDefinition<Submission>("net_id", Submission::netId),
@@ -32,6 +29,7 @@ public class SubmissionSqlDao implements SubmissionDao {
             new ColumnDefinition<Submission>("rubric", s -> new Gson().toJson(s.rubric())),
             new ColumnDefinition<Submission>("admin", Submission::admin)
     };
+
     private static Submission readSubmission(ResultSet rs) throws SQLException {
         String netId = rs.getString("net_id");
         String repoUrl = rs.getString("repo_url");
@@ -55,6 +53,7 @@ private static Submission readSubmission(ResultSet rs) throws SQLException {
     public void insertSubmission(Submission submission) throws DataAccessException {
         sqlReader.insertItem(submission);
     }
+
     @Override
     public Collection<Submission> getSubmissionsForPhase(String netId, Phase phase) throws DataAccessException {
         return sqlReader.executeQuery(
@@ -80,30 +79,43 @@ public Collection<Submission> getAllLatestSubmissions() throws DataAccessExcepti
 
     @Override
     public Collection<Submission> getAllLatestSubmissions(int batchSize) throws DataAccessException {
-        return sqlReader.executeQuery(
-                """
-                    WHERE timestamp IN (
-                        SELECT MAX(timestamp)
-                        FROM %s
-                        GROUP BY net_id, phase
-                    )
-                    ORDER BY timestamp DESC
-                    """.formatted(sqlReader.getTableName()) +
-                (batchSize >= 0 ? "LIMIT ?" : ""),
-                ps -> {
-                    if (batchSize >= 0) {
-                        ps.setInt(1, batchSize);
-                    }
-                });
+        try (var connection = SqlDb.getConnection()) {
+            var statement = connection.prepareStatement(
+                    """
+                            SELECT s.net_id, s.repo_url, s.timestamp, s.phase, s.passed, s.score, s.num_commits, s.head_hash, s.notes, s.rubric, s.admin
+                            FROM submission s
+                            INNER JOIN (
+                                SELECT net_id, phase, MAX(timestamp) AS max_timestamp
+                                FROM submission
+                                GROUP BY net_id, phase
+                            ) s2 ON s.net_id = s2.net_id AND s.phase = s2.phase AND s.timestamp = s2.max_timestamp
+                            ORDER BY s2.max_timestamp DESC
+                            """ +
+                            (batchSize >= 0 ? "LIMIT ?" : "")
+            );
+            if (batchSize >= 0) {
+                statement.setInt(1, batchSize);
+            }
+            try (var results = statement.executeQuery()) {
+                List<Submission> submissions = new ArrayList<>();
+                while (results.next()) {
+                    Submission submission = readSubmission(results);
+                    submissions.add(submission);
+                }
+                return submissions;
+            }
+        } catch (SQLException e) {
+            throw new DataAccessException("Error getting latest submissions", e);
+        }
     }
 
     @Override
     public void removeSubmissionsByNetId(String netId) throws DataAccessException {
         sqlReader.executeUpdate(
                 """
-                    DELETE FROM %s
-                    WHERE net_id = ?
-                    """.formatted(sqlReader.getTableName()),
+                        DELETE FROM %s
+                        WHERE net_id = ?
+                        """.formatted(sqlReader.getTableName()),
                 ps -> ps.setString(1, netId)
         );
     }
@@ -128,10 +140,10 @@ public Submission getFirstPassingSubmission(String netId, Phase phase) throws Da
     public float getBestScoreForPhase(String netId, Phase phase) throws DataAccessException {
         return sqlReader.executeQuery(
                 """
-                    SELECT max(score) as highestScore
-                    FROM %s
-                    WHERE net_id = ? AND phase = ?
-                    """.formatted(sqlReader.getTableName()),
+                        SELECT max(score) as highestScore
+                        FROM %s
+                        WHERE net_id = ? AND phase = ?
+                        """.formatted(sqlReader.getTableName()),
                 ps -> {
                     ps.setString(1, netId);
                     ps.setString(2, phase.toString());