perf: fix remaining medium and low severity performance issues (#370)

* perf: fix remaining medium and low severity performance issues

Medium fixes:
- Coalesce NSWindow.didUpdateNotification into one check per run loop (MED-2)
- Increase SSH relay poll timeout from 100ms to 500ms (MED-3)
- Skip tab persistence on column-layout-only changes (MED-4)
- Use toQueryResultRows() with reserveCapacity (MED-9)
- Add single-column sort fast path avoiding key pre-extraction (MED-17)

Low fixes:
- Cache queryBuildingDriver probe result per database type (LOW-2)
- Cache column type classification in PluginDriverAdapter (LOW-3)
- Use NSString character-at-index in substituteQuestionMarks (LOW-4)
- Remove redundant onChange(of: tabs.count) observer (LOW-5)
- Replace inline tabs.map(\.id) with tracked tabIds property (LOW-6)
- Count newlines without array allocation in CellOverlayEditor (LOW-7)
- Single-pass delimiter detection in RowOperationsManager (LOW-7)
- Replace 6x linear string scans with single alternation regex (LOW-8)
- Lowercase aliasOrName once in resolveAlias (LOW-9)
- Use Set<TableReference> for O(1) dedup in autocomplete (LOW-10)
- Consolidate 40+ keyword regexes into single alternation per color (LOW-11)
- In-place index mutation in removeRow instead of .map (LOW-12)
- Guard scroll observer when no inline suggestion active (LOW-13)

* fix: address CodeRabbit review feedback

- Remove force-unwrap in SQLFormatterService majorKeywordRegex match
- Add explicit internal access control on TableReference
- Cap DDL highlight regex to 10k characters for large DDL safety
- Fix CRLF double-counting in CellOverlayEditor newline counter
- Invalidate queryBuildingDriverCache on plugin register/uninstall
- Use DispatchQueue.main.async for isUpdatingColumnLayout flag reset

* fix: invalidate queryBuildingDriverCache in setEnabled()

Author: datlechin

Plugins/TableProPluginKit/PluginDatabaseDriver.swift

@@ -269,41 +269,55 @@ public extension PluginDatabaseDriver {
     }
 
     private static func substituteQuestionMarks(query: String, parameters: [String?]) -> String {
+        let nsQuery = query as NSString
+        let length = nsQuery.length
         var sql = ""
         var paramIndex = 0
         var inSingleQuote = false
         var inDoubleQuote = false
         var isEscaped = false
+        var i = 0
+
+        let backslash: UInt16 = 0x5C // \\
+        let singleQuote: UInt16 = 0x27 // '
+        let doubleQuote: UInt16 = 0x22 // "
+        let questionMark: UInt16 = 0x3F // ?
+
+        while i < length {
+            let char = nsQuery.character(at: i)
 
-        for char in query {
             if isEscaped {
                 isEscaped = false
-                sql.append(char)
+                sql.append(Character(UnicodeScalar(char)!))
+                i += 1
                 continue
             }
 
-            if char == "\\" && (inSingleQuote || inDoubleQuote) {
+            if char == backslash && (inSingleQuote || inDoubleQuote) {
                 isEscaped = true
-                sql.append(char)
+                sql.append(Character(UnicodeScalar(char)!))
+                i += 1
                 continue
             }
 
-            if char == "'" && !inDoubleQuote {
+            if char == singleQuote && !inDoubleQuote {
                 inSingleQuote.toggle()
-            } else if char == "\"" && !inSingleQuote {
+            } else if char == doubleQuote && !inSingleQuote {
                 inDoubleQuote.toggle()
             }
 
-            if char == "?" && !inSingleQuote && !inDoubleQuote && paramIndex < parameters.count {
+            if char == questionMark && !inSingleQuote && !inDoubleQuote && paramIndex < parameters.count {
                 if let value = parameters[paramIndex] {
                     sql.append(escapedParameterValue(value))
                 } else {
                     sql.append("NULL")
                 }
                 paramIndex += 1
             } else {
-                sql.append(char)
+                sql.append(Character(UnicodeScalar(char)!))
             }
+
+            i += 1
         }
 
         return sql

TablePro/Core/AI/InlineSuggestionManager.swift

@@ -430,6 +430,7 @@ final class InlineSuggestionManager {
                 object: contentView,
                 queue: .main
             ) { [weak self] _ in
+                guard self?.currentSuggestion != nil else { return }
                 Task { @MainActor [weak self] in
                     guard let self else { return }
                     if let suggestion = self.currentSuggestion {

TablePro/Core/Autocomplete/SQLContextAnalyzer.swift

@@ -41,7 +41,7 @@ enum SQLClauseType {
 }
 
 /// Represents a table reference with optional alias
-struct TableReference: Equatable, Sendable {
+internal struct TableReference: Hashable, Sendable {
     let tableName: String
     let alias: String?
 
@@ -344,22 +344,23 @@ final class SQLContextAnalyzer {
 
         // Find all table references in the current statement
         var tableReferences = extractTableReferences(from: currentStatement)
+        var seenReferences = Set<TableReference>(tableReferences)
 
         // Extract CTEs from the current statement
         let cteNames = extractCTENames(from: currentStatement)
 
         // Add CTE names as table references
         for cteName in cteNames {
             let cteRef = TableReference(tableName: cteName, alias: nil)
-            if !tableReferences.contains(cteRef) {
+            if seenReferences.insert(cteRef).inserted {
                 tableReferences.append(cteRef)
             }
         }
 
         // Extract ALTER TABLE table name and add to references
         if let alterTableName = extractAlterTableName(from: currentStatement) {
             let alterRef = TableReference(tableName: alterTableName, alias: nil)
-            if !tableReferences.contains(alterRef) {
+            if seenReferences.insert(alterRef).inserted {
                 tableReferences.append(alterRef)
             }
         }
@@ -782,6 +783,7 @@ final class SQLContextAnalyzer {
     /// Extract all table references (table names and aliases) from the query
     private func extractTableReferences(from query: String) -> [TableReference] {
         var references: [TableReference] = []
+        var seen = Set<TableReference>()
 
         // SQL keywords that should NOT be treated as table names
         let sqlKeywords: Set<String> = [
@@ -816,7 +818,7 @@ final class SQLContextAnalyzer {
                 }
 
                 let ref = TableReference(tableName: tableName, alias: alias)
-                if !references.contains(ref) {
+                if seen.insert(ref).inserted {
                     references.append(ref)
                 }
             }

TablePro/Core/Autocomplete/SQLSchemaProvider.swift

@@ -118,23 +118,25 @@ actor SQLSchemaProvider {
 
     /// Find table name from alias
     func resolveAlias(_ aliasOrName: String, in references: [TableReference]) -> String? {
+        let lowerName = aliasOrName.lowercased()
+
         // First check if it's an alias
         for ref in references {
-            if ref.alias?.lowercased() == aliasOrName.lowercased() {
+            if ref.alias?.lowercased() == lowerName {
                 return ref.tableName
             }
         }
 
         // Then check if it's a table name directly
         for ref in references {
-            if ref.tableName.lowercased() == aliasOrName.lowercased() {
+            if ref.tableName.lowercased() == lowerName {
                 return ref.tableName
             }
         }
 
         // Finally check against known tables
         for table in tables {
-            if table.name.lowercased() == aliasOrName.lowercased() {
+            if table.name.lowercased() == lowerName {
                 return table.name
             }
         }

TablePro/Core/Plugins/PluginDriverAdapter.swift

@@ -11,6 +11,7 @@ final class PluginDriverAdapter: DatabaseDriver, SchemaSwitchable {
     let connection: DatabaseConnection
     private(set) var status: ConnectionStatus = .disconnected
     private let pluginDriver: any PluginDatabaseDriver
+    private var columnTypeCache: [String: ColumnType] = [:]
 
     var serverVersion: String? { pluginDriver.serverVersion }
     var parameterStyle: ParameterStyle { pluginDriver.parameterStyle }
@@ -421,6 +422,13 @@ final class PluginDriverAdapter: DatabaseDriver, SchemaSwitchable {
     }
 
     private func mapColumnType(rawTypeName: String) -> ColumnType {
+        if let cached = columnTypeCache[rawTypeName] { return cached }
+        let result = classifyColumnType(rawTypeName: rawTypeName)
+        columnTypeCache[rawTypeName] = result
+        return result
+    }
+
+    private func classifyColumnType(rawTypeName: String) -> ColumnType {
         let upper = rawTypeName.uppercased()
 
         if upper.contains("BOOL") {

TablePro/Core/Plugins/PluginManager.swift

@@ -57,6 +57,8 @@ final class PluginManager {
 
     private var pendingPluginURLs: [(url: URL, source: PluginSource)] = []
 
+    private var queryBuildingDriverCache: [String: (any PluginDatabaseDriver)?] = [:]
+
     private init() {}
 
     private func migrateDisabledPluginsKey() {
@@ -207,6 +209,8 @@ final class PluginManager {
 
             Self.logger.info("Loaded plugin '\(entry.name)' v\(entry.version) [\(item.source == .builtIn ? "built-in" : "user")]")
         }
+
+        queryBuildingDriverCache.removeAll()
     }
 
     private func discoverAllPlugins() {
@@ -247,6 +251,7 @@ final class PluginManager {
             }
         }
 
+        queryBuildingDriverCache.removeAll()
         hasFinishedInitialLoad = true
         validateDependencies()
         Self.logger.info("Loaded \(self.plugins.count) plugin(s): \(self.driverPlugins.count) driver(s), \(self.exportPlugins.count) export format(s), \(self.importPlugins.count) import format(s)")
@@ -622,13 +627,23 @@ final class PluginManager {
     /// Returns a temporary plugin driver for query building (buildBrowseQuery), or nil
     /// if the plugin doesn't implement custom query building (NoSQL hooks).
     func queryBuildingDriver(for databaseType: DatabaseType) -> (any PluginDatabaseDriver)? {
-        guard let plugin = driverPlugin(for: databaseType) else { return nil }
+        let typeId = databaseType.pluginTypeId
+        if let cached = queryBuildingDriverCache[typeId] { return cached }
+        guard let plugin = driverPlugin(for: databaseType) else {
+            if hasFinishedInitialLoad {
+                queryBuildingDriverCache[typeId] = .some(nil)
+            }
+            return nil
+        }
         let config = DriverConnectionConfig(host: "", port: 0, username: "", password: "", database: "")
         let driver = plugin.createDriver(config: config)
-        guard driver.buildBrowseQuery(table: "_probe", sortColumns: [], columns: [], limit: 1, offset: 0) != nil else {
-            return nil
+        let result: (any PluginDatabaseDriver)? =
+            driver.buildBrowseQuery(table: "_probe", sortColumns: [], columns: [], limit: 1, offset: 0) != nil
+            ? driver : nil
+        if hasFinishedInitialLoad {
+            queryBuildingDriverCache[typeId] = .some(result)
         }
-        return driver
+        return result
     }
 
     func editorLanguage(for databaseType: DatabaseType) -> EditorLanguage {
@@ -856,6 +871,7 @@ final class PluginManager {
             unregisterCapabilities(pluginId: pluginId)
         }
 
+        queryBuildingDriverCache.removeAll()
         Self.logger.info("Plugin '\(pluginId)' \(enabled ? "enabled" : "disabled")")
     }
 
@@ -1005,6 +1021,8 @@ final class PluginManager {
         disabled.remove(id)
         disabledPluginIds = disabled
 
+        queryBuildingDriverCache.removeAll()
+
         Self.logger.info("Uninstalled plugin '\(id)'")
         _needsRestart = true
     }

TablePro/Core/SSH/LibSSH2Tunnel.swift

@@ -358,7 +358,7 @@ internal final class LibSSH2Tunnel: @unchecked Sendable {
                 pollfd(fd: self.socketFD, events: Int16(POLLIN), revents: 0),
             ]
 
-            let pollResult = poll(&pollFDs, 2, 100) // 100ms timeout
+            let pollResult = poll(&pollFDs, 2, 500) // 500ms timeout
             if pollResult < 0 { break }
 
             // Read from SSH channel when the SSH socket has data or on timeout

TablePro/Core/SSH/LibSSH2TunnelFactory.swift

@@ -485,7 +485,7 @@ internal enum LibSSH2TunnelFactory {
                             pollfd(fd: sshSocketFD, events: Int16(POLLIN), revents: 0),
                         ]
 
-                        let pollResult = poll(&pollFDs, 2, 100)
+                        let pollResult = poll(&pollFDs, 2, 500)
                         if pollResult < 0 { break }
 
                         // Channel -> socketpair (serialized libssh2 call)

TablePro/Core/Services/Formatting/SQLFormatterService.swift

@@ -92,6 +92,10 @@ struct SQLFormatterService: SQLFormatterProtocol {
     }()
 
     /// WHERE condition alignment pattern: \s+(AND|OR)\s+
+    private static let majorKeywordRegex: NSRegularExpression = {
+        regex("\\b(ORDER|GROUP|HAVING|LIMIT|UNION|INTERSECT)\\b", options: .caseInsensitive)
+    }()
+
     private static let whereConditionRegex: NSRegularExpression = {
         regex("\\s+(AND|OR)\\s+", options: .caseInsensitive)
     }()
@@ -471,14 +475,14 @@ struct SQLFormatterService: SQLFormatterProtocol {
             return sql
         }
 
-        // Find end of WHERE clause
-        let majorKeywords = ["ORDER", "GROUP", "HAVING", "LIMIT", "UNION", "INTERSECT"]
+        // Find end of WHERE clause using single regex scan
+        let searchStart = whereRange.upperBound
+        let searchNSRange = NSRange(searchStart..<sql.endIndex, in: sql)
         var endIndex = sql.endIndex
 
-        for keyword in majorKeywords {
-            if let range = sql.range(of: keyword, options: .caseInsensitive, range: whereRange.upperBound..<sql.endIndex) {
-                endIndex = min(endIndex, range.lowerBound)
-            }
+        if let match = Self.majorKeywordRegex.firstMatch(in: sql, range: searchNSRange),
+           let matchRange = Range(match.range, in: sql) {
+            endIndex = matchRange.lowerBound
         }
 
         // Fix #3: Work with immutable substring

TablePro/Core/Services/Query/RowOperationsManager.swift

@@ -394,12 +394,41 @@ final class RowOperationsManager {
     /// Auto-detect whether clipboard text is CSV or TSV
     /// Heuristic: if tabs appear in most lines, use TSV; otherwise CSV
     static func detectParser(for text: String) -> RowDataParser {
-        let lines = text.components(separatedBy: .newlines)
-            .filter { !$0.trimmingCharacters(in: .whitespaces).isEmpty }
-        guard !lines.isEmpty else { return TSVRowParser() }
+        // Single-pass scan: count non-empty lines containing tabs vs commas
+        var tabLines = 0
+        var commaLines = 0
+        var nonEmptyLines = 0
+        var lineHasTab = false
+        var lineHasComma = false
+        var lineIsEmpty = true
+
+        for char in text {
+            if char.isNewline {
+                if !lineIsEmpty {
+                    nonEmptyLines += 1
+                    if lineHasTab { tabLines += 1 }
+                    if lineHasComma { commaLines += 1 }
+                }
+                lineHasTab = false
+                lineHasComma = false
+                lineIsEmpty = true
+            } else {
+                if !char.isWhitespace { lineIsEmpty = false }
+                if char == "\t" { lineHasTab = true }
+                if char == "," { lineHasComma = true }
+            }
+        }
+        // Handle last line (no trailing newline)
+        if !lineIsEmpty {
+            nonEmptyLines += 1
+            if lineHasTab { tabLines += 1 }
+            if lineHasComma { commaLines += 1 }
+        }
+
+        guard nonEmptyLines > 0 else { return TSVRowParser() }
 
-        let tabCount = lines.count(where: { $0.contains("\t") })
-        let commaCount = lines.count(where: { $0.contains(",") })
+        let tabCount = tabLines
+        let commaCount = commaLines
 
         // If majority of lines have tabs, use TSV; otherwise CSV
         if tabCount > commaCount {