Improved MySQL index handling (fixes #867)

src/main/java/net/coreprotect/database/Database.java

@@ -12,6 +12,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.TreeMap;
 
 import org.bukkit.Location;
 import org.bukkit.Material;
@@ -326,6 +327,7 @@ public class Database extends Queue {
             if (connection != null) {
                 Statement statement = connection.createStatement();
                 createMySQLTableStructures(prefix, statement);
+                createMySQLIndexes(prefix, statement, purge);
                 if (!purge && forceConnection == null) {
                     initializeTables(prefix, statement);
                 }
@@ -413,6 +415,103 @@ public class Database extends Queue {
         statement.executeUpdate("CREATE TABLE IF NOT EXISTS " + prefix + "world(rowid int NOT NULL AUTO_INCREMENT,PRIMARY KEY(rowid),id int,world varchar(255)" + index + ") ENGINE=InnoDB DEFAULT CHARACTER SET utf8mb4");
     }
 
+    private static void createMySQLIndexes(String prefix, Statement statement, boolean purge) {
+        try {
+            ensureMySQLIndex(statement, prefix + "block", "wid", "x", "z", "time");
+            ensureMySQLIndex(statement, prefix + "block", "user", "time");
+            ensureMySQLIndex(statement, prefix + "block", "type", "time");
+            ensureMySQLIndex(statement, prefix + "container", "wid", "x", "z", "time");
+            ensureMySQLIndex(statement, prefix + "container", "user", "time");
+            ensureMySQLIndex(statement, prefix + "container", "type", "time");
+            ensureMySQLIndex(statement, prefix + "item", "wid", "x", "z", "time");
+            ensureMySQLIndex(statement, prefix + "item", "user", "time");
+            ensureMySQLIndex(statement, prefix + "item", "type", "time");
+        }
+        catch (Exception e) {
+            Chat.console(Phrase.build(Phrase.DATABASE_INDEX_ERROR));
+            if (purge) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    private static void ensureMySQLIndex(Statement statement, String tableName, String... columns) throws SQLException {
+        if (hasMySQLIndex(statement, tableName, columns)) {
+            return;
+        }
+
+        String indexName = createMySQLIndexName(tableName, columns);
+        String indexColumns = String.join(",", columns);
+        statement.executeUpdate("CREATE INDEX " + indexName + " ON " + tableName + "(" + indexColumns + ")");
+    }
+
+    private static boolean hasMySQLIndex(Statement statement, String tableName, String... columns) {
+        Map<String, TreeMap<Integer, String>> indexData = new HashMap<>();
+
+        try (ResultSet resultSet = statement.executeQuery("SHOW INDEX FROM " + tableName)) {
+            while (resultSet.next()) {
+                String keyName = resultSet.getString("Key_name");
+                int sequence = resultSet.getInt("Seq_in_index");
+                String columnName = resultSet.getString("Column_name");
+                if (keyName == null || columnName == null) {
+                    continue;
+                }
+
+                indexData.computeIfAbsent(keyName, key -> new TreeMap<>()).put(sequence, columnName.toLowerCase(Locale.ROOT));
+            }
+        }
+        catch (Exception e) {
+            return false;
+        }
+
+        List<String> expected = new ArrayList<>(columns.length);
+        for (String column : columns) {
+            expected.add(column.toLowerCase(Locale.ROOT));
+        }
+
+        for (TreeMap<Integer, String> indexColumns : indexData.values()) {
+            if (indexColumns.size() < expected.size()) {
+                continue;
+            }
+
+            boolean matchesPrefix = true;
+            int position = 0;
+            for (String column : indexColumns.values()) {
+                if (!column.equals(expected.get(position))) {
+                    matchesPrefix = false;
+                    break;
+                }
+                position++;
+                if (position == expected.size()) {
+                    break;
+                }
+            }
+
+            if (matchesPrefix && position == expected.size()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private static String createMySQLIndexName(String tableName, String... columns) {
+        String normalizedTable = tableName.replaceAll("[^A-Za-z0-9_]", "_");
+        String joinedColumns = String.join("_", columns);
+        String candidate = normalizedTable + "_" + joinedColumns + "_idx";
+        if (candidate.length() <= 64) {
+            return candidate;
+        }
+
+        String hash = Integer.toHexString(candidate.hashCode());
+        int maxPrefixLength = 64 - (hash.length() + 1);
+        if (maxPrefixLength < 1) {
+            maxPrefixLength = 1;
+        }
+
+        return candidate.substring(0, maxPrefixLength) + "_" + hash;
+    }
+
     private static void createSQLiteTables(String prefix, boolean forcePrefix, Connection forceConnection, boolean purge) {
         try (Connection connection = (forceConnection != null ? forceConnection : Database.getConnection(true, 0))) {
             Statement statement = connection.createStatement();

src/main/java/net/coreprotect/database/LookupRaw.java

@@ -586,17 +586,17 @@ public class LookupRaw extends Queue {
             String unionSelect = "SELECT * FROM (";
             if (Config.getGlobal().MYSQL) {
                 if (queryTable.equals("block")) {
-                    if (includeBlock.length() > 0 || includeEntity.length() > 0) {
-                        index = "USE INDEX(type) IGNORE INDEX(user,wid) ";
-                    }
-                    if (users.length() > 0) {
-                        index = "USE INDEX(user) IGNORE INDEX(type,wid) ";
-                    }
                     if (radius != null && (radius[2] - radius[1]) <= 50 && (radius[6] - radius[5]) <= 50) {
-                        index = "USE INDEX(wid) IGNORE INDEX(type,user) ";
+                        index = "USE INDEX(wid) ";
                     }
-                    if ((restrictWorld && (users.length() > 0 || includeBlock.length() > 0 || includeEntity.length() > 0))) {
+                    else if (users.length() > 0) {
-                        index = "IGNORE INDEX(PRIMARY) ";
+                        index = "USE INDEX(user) ";
+                    }
+                    else if (includeBlock.length() > 0 || includeEntity.length() > 0) {
+                        index = "USE INDEX(type) ";
+                    }
+                    else if (restrictWorld) {
+                        index = "USE INDEX(wid) ";
                     }
                 }