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MeBox/internal/database/schema_migration.go
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2026-10-11 23:44:11 +08:00

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package database
import (
"fmt"
"strings"
"go.uber.org/zap"
"gorm.io/gorm"
"github.com/truewhile/MeBox/internal/config"
"github.com/truewhile/MeBox/internal/model"
)
// AutoMigrate creates tables for every model registered in the model package.
func AutoMigrate(db *gorm.DB) error {
return AutoMigrateWithConfig(db, nil, nil)
}
// AutoMigrateWithConfig 与 AutoMigrate 相同,另外接受配置与日志:
// 配置用来决定可选的 PostgreSQL 搜索索引,日志用来记录耗时步骤
// (首次在已有大库上重建索引可能需要数十秒)。两者都可以为 nil。
func AutoMigrateWithConfig(db *gorm.DB, cfg *config.Config, log *zap.Logger) error {
// 必须先于 AutoMigrate:旧库中可能已有重复的 (user_id, media_id) 历史行,
// 不去重会导致唯一索引 uniq_user_history 创建失败。
if err := dedupePlaybackHistories(db); err != nil {
return err
}
// 书源从「全局唯一」改成「按用户独立」:先删掉 source_url 上的旧唯一索引。
// AutoMigrate 只会按索引名创建新索引,不会删除已改名的旧唯一索引,留着它
// 第二个用户导入同一书源就会撞唯一约束。
if err := dropLegacyReaderSourceUniqueIndex(db); err != nil {
return err
}
if err := db.AutoMigrate(model.AllModels()...); err != nil {
return err
}
// 回填书源归属:老库的书源没有 user_id,按「谁书架上有这本书」分配或复制副本。
if err := backfillReaderSourceOwnership(db); err != nil {
return err
}
if err := ensurePostgresColumnCompatibility(db); err != nil {
return err
}
if err := ensurePerformanceIndexes(db); err != nil {
return err
}
if err := ensureMediaPathIndex(db); err != nil {
return err
}
if err := ensureLibraryRootsCompatibility(db); err != nil {
return err
}
if err := ensureEmbyMountsCompatibility(db); err != nil {
return err
}
if isSQLite(db) {
if err := ensureMediaSearchIndex(db); err != nil {
return err
}
return ensureSQLiteQueryOptimizer(db)
}
return ensurePostgresSearchIndexes(db, cfg, log)
}
// ensureMediaPathIndex 建立 media.path 的唯一约束与等值查找索引。
//
// 模型上不再用 gorm:"uniqueIndex"(见 model.Media.Path 的注释):PostgreSQL 的
// btree 单条索引项上限是 2704 字节,varchar(1024) 在中文路径下可达 3072 字节,
// 对整列建唯一索引会让这类行插入时报
//
// index row size ... exceeds btree version 4 maximum 2704
//
// 所以 PostgreSQL 改用 md5(path) 的表达式唯一索引(定长 32 字节,永远塞得下),
// 同时保留一条普通索引 idx_media_path 供 path = ? 等值查找(扫描与 upsert 的
// 热路径)使用。SQLite 没有这个长度限制,沿用整列唯一索引。
func ensureMediaPathIndex(db *gorm.DB) error {
if db == nil || !db.Migrator().HasTable("media") {
return nil
}
if !isPostgres(db) {
return db.Exec(`CREATE UNIQUE INDEX IF NOT EXISTS idx_media_path ON media(path)`).Error
}
// 先建哈希唯一索引:此时旧索引还在,唯一性不会出现空窗。
if err := db.Exec(`CREATE UNIQUE INDEX IF NOT EXISTS idx_media_path_hash ON media(md5(path))`).Error; err != nil {
return err
}
unique, found, err := postgresIndexIsUnique(db, "idx_media_path")
if err != nil {
return err
}
if found && unique {
if err := db.Exec(`DROP INDEX IF EXISTS idx_media_path`).Error; err != nil {
return err
}
}
return db.Exec(`CREATE INDEX IF NOT EXISTS idx_media_path ON media(path)`).Error
}
// postgresIndexIsUnique 报告当前 schema 下是否存在该索引、以及它是否唯一。
func postgresIndexIsUnique(db *gorm.DB, indexName string) (unique bool, found bool, err error) {
// 用指针接 bool:没有匹配行时 Scan 不报错,nil 即代表索引不存在。
var row struct {
IsUnique *bool
}
if err := db.Raw(`
SELECT i.indisunique AS is_unique
FROM pg_class c
JOIN pg_index i ON i.indexrelid = c.oid
JOIN pg_namespace n ON n.oid = c.relnamespace
WHERE n.nspname = current_schema() AND c.relname = ?
`, indexName).Scan(&row).Error; err != nil {
return false, false, err
}
if row.IsUnique == nil {
return false, false, nil
}
return *row.IsUnique, true, nil
}
// ensurePostgresSearchIndexes 给 PostgreSQL 补上 SQLite FTS5 的替代品。
//
// 全文检索只在 SQLite 下存在(FTS5 虚表 + 触发器),PostgreSQL 下
// media_search_repository 会退回 title/original_name/path/genres 的 ILIKE
// 全表扫描。pg_trgm 的 GIN 三元组索引能让这类 '%term%' 模式(≥3 字符)走索引,
// 把搜索从整表扫描降到索引扫描。
//
// 之所以可关闭:media 表写入非常频繁(每次扫描批量入库),多 4 个 GIN 索引会
// 明显放大写入成本。默认开启以对齐 SQLite 的搜索能力,写入压力大的部署可以关掉。
//
// 整个过程是尽力而为:没有建扩展的权限、Postgres 版本不支持等情况下只记一条
// 警告并继续启动,绝不让一个搜索加速项把服务挡在门外。
func ensurePostgresSearchIndexes(db *gorm.DB, cfg *config.Config, log *zap.Logger) error {
if !isPostgres(db) {
return nil
}
if cfg != nil && !cfg.Database.PostgresTrgmIndex {
if log != nil {
log.Info("postgres trigram search index disabled; media search falls back to sequential scan")
}
return nil
}
if err := db.Exec(`CREATE EXTENSION IF NOT EXISTS pg_trgm`).Error; err != nil {
if log != nil {
log.Warn("create pg_trgm extension failed; media search falls back to sequential scan", zap.Error(err))
}
return nil
}
// 首次在已有大库上执行会重建索引(服务尚未开始接受请求),之后每次启动都因
// IF NOT EXISTS 直接跳过。
if log != nil {
log.Info("ensuring postgres trigram search indexes")
}
for _, stmt := range []string{
`CREATE INDEX IF NOT EXISTS idx_media_title_trgm ON media USING gin (title gin_trgm_ops)`,
`CREATE INDEX IF NOT EXISTS idx_media_original_name_trgm ON media USING gin (original_name gin_trgm_ops)`,
`CREATE INDEX IF NOT EXISTS idx_media_path_trgm ON media USING gin (path gin_trgm_ops)`,
`CREATE INDEX IF NOT EXISTS idx_media_genres_trgm ON media USING gin (genres gin_trgm_ops)`,
} {
if err := db.Exec(stmt).Error; err != nil {
if log != nil {
log.Warn("create trigram index failed; media search may fall back to sequential scan",
zap.String("statement", stmt), zap.Error(err))
}
return nil
}
}
return nil
}
func ensureSQLiteQueryOptimizer(db *gorm.DB) error {
// Refresh planner statistics so indexes on large media tables are used.
return db.Exec("ANALYZE").Error
}
// dropLegacyReaderSourceUniqueIndex 删除书源表上旧版 source_url 唯一索引。
//
// 书源改为按用户独立后唯一键是 (user_id, source_url);SQLite 的 RenameTable 与
// AutoMigrate 都不会删除按旧名创建的索引(实测旧唯一索引在改名后依然生效),
// 必须显式删除,否则第二个用户导入同一书源会撞唯一约束。
func dropLegacyReaderSourceUniqueIndex(db *gorm.DB) error {
if !db.Migrator().HasTable(&model.ReaderBookSource{}) {
return nil
}
for _, name := range []string{"idx_reader_book_sources_source_url", "reader_book_sources_source_url_key"} {
if db.Migrator().HasIndex(&model.ReaderBookSource{}, name) {
if err := db.Migrator().DropIndex(&model.ReaderBookSource{}, name); err != nil {
return err
}
}
}
// 旧版 DeleteSource 是软删:这些历史行会继续占用 (user_id, source_url) 唯一键,
// 让「删掉再导入同一书源」失败。书源是可重新导入的数据,这里一次性清掉。
return db.Unscoped().Where("deleted_at IS NOT NULL").Delete(&model.ReaderBookSource{}).Error
}
// backfillReaderSourceOwnership 给老库的书源补上归属用户。
//
// 书源原先全局唯一,现在按用户独立:按「谁的书架上有这本书」把书源分配给该用户;
// 同一书源被多个用户引用时,给每个用户复制一份副本(各自启停/排序/改规则),
// 这样谁都不会因为别人删源而失去书源。
//
// 没有 user_id 且无人引用的书源保持原样(user_id 为空)——它不再出现在任何人的
// 列表里,但数据仍在,需要时可以人工认领。
func backfillReaderSourceOwnership(db *gorm.DB) error {
if !db.Migrator().HasTable(&model.ReaderBookSource{}) {
return nil
}
var pending []model.ReaderBookSource
if err := db.Where("user_id = '' OR user_id IS NULL").Find(&pending).Error; err != nil {
return err
}
for i := range pending {
src := pending[i]
if err := assignOrCloneReaderSource(db, &src); err != nil {
return err
}
}
return nil
}
func assignOrCloneReaderSource(db *gorm.DB, src *model.ReaderBookSource) error {
if src == nil || src.SourceURL == "" {
return nil
}
// 引用该书源的书籍分布(去重到用户)。
type ownerCount struct {
UserID string
N int64
}
var owners []ownerCount
if err := db.Model(&model.ReaderBook{}).
Select("user_id, COUNT(*) AS n").
Where("origin = ?", src.SourceURL).
Group("user_id").Order("n DESC").Scan(&owners).Error; err != nil {
return err
}
if len(owners) == 0 {
return nil // 无人引用:保持无归属
}
// 第一个用户(引用最多)直接接手这一行。
owner := owners[0].UserID
if owner == "" {
return nil
}
if err := db.Model(&model.ReaderBookSource{}).
Where("id = ?", src.ID).
Updates(map[string]any{"user_id": owner}).Error; err != nil {
return err
}
// 其余用户各复制一份副本(新行 ID,其余字段全量拷贝)。
for _, o := range owners[1:] {
if o.UserID == "" || o.UserID == owner {
continue
}
var exists int64
if err := db.Model(&model.ReaderBookSource{}).
Where("user_id = ? AND source_url = ?", o.UserID, src.SourceURL).
Count(&exists).Error; err != nil {
return err
}
if exists > 0 {
continue
}
clone := *src
clone.ID = ""
clone.UserID = o.UserID
if err := db.Create(&clone).Error; err != nil {
return err
}
}
return nil
}
// dedupePlaybackHistories removes duplicate (user_id, media_id) rows left by
// the former read-then-write upsert, so the uniq_user_history composite unique
// index can be created on existing databases. Keeps the most recent row per
// pair, preferring live rows over soft-deleted ones.
func dedupePlaybackHistories(db *gorm.DB) error {
if !db.Migrator().HasTable("playback_histories") {
return nil
}
return db.Exec(`
DELETE FROM playback_histories WHERE id IN (
SELECT id FROM (
SELECT id, ROW_NUMBER() OVER (
PARTITION BY user_id, media_id
ORDER BY deleted_at IS NULL DESC, watched_at DESC, id DESC
) AS rn
FROM playback_histories
) ranked
WHERE ranked.rn > 1
)`).Error
}
func ensurePostgresColumnCompatibility(db *gorm.DB) error {
if !isPostgres(db) {
return nil
}
// 只在类型确实不匹配时才 ALTER。
//
// PostgreSQL 的 ALTER COLUMN ... TYPE 只要类型声明与目标不同就会整表重写并
// 重建相关索引,执行期间持有 ACCESS EXCLUSIVE 锁。此前这里每次启动都无条件
// 发这 7 条语句:类型其实早已一致,但几十万行的 media 表仍然被反复重写,
// 启动会卡住数分钟,且期间这张表连读都被阻塞。
changes := []struct {
table string
column string
target string
}{
{"media", "container", "varchar(128)"},
{"media", "genres", "text"},
{"media", "series_id", "varchar(128)"},
{"media", "duplicate_of", "varchar(128)"},
{"playback_histories", "media_id", "varchar(128)"},
{"favorites", "media_id", "varchar(128)"},
{"playlist_items", "media_id", "varchar(128)"},
}
for _, change := range changes {
current, found, err := postgresColumnType(db, change.table, change.column)
if err != nil {
return err
}
if !found || current == change.target {
continue
}
stmt := "ALTER TABLE " + quoteIdent(change.table) +
" ALTER COLUMN " + quoteIdent(change.column) + " TYPE " + change.target
if err := db.Exec(stmt).Error; err != nil {
return err
}
}
return nil
}
// postgresColumnType 返回列在当前 schema 下的规范化类型描述,例如
// "varchar(128)" / "text"。列不存在时 found 为 false。
func postgresColumnType(db *gorm.DB, table, column string) (value string, found bool, err error) {
var row struct {
DataType string
MaxLength *int64
}
if err := db.Raw(`
SELECT data_type AS data_type, character_maximum_length AS max_length
FROM information_schema.columns
WHERE table_schema = current_schema() AND table_name = ? AND column_name = ?
`, table, column).Scan(&row).Error; err != nil {
return "", false, fmt.Errorf("inspect postgres column %s.%s: %w", table, column, err)
}
dataType := strings.ToLower(strings.TrimSpace(row.DataType))
if dataType == "" {
return "", false, nil
}
// information_schema 用的是 SQL 标准名,映射回 GORM 标签里的写法再比较。
switch dataType {
case "character varying", "varchar":
dataType = "varchar"
}
if row.MaxLength != nil && *row.MaxLength > 0 {
dataType = fmt.Sprintf("%s(%d)", dataType, *row.MaxLength)
}
return dataType, true, nil
}
func ensurePerformanceIndexes(db *gorm.DB) error {
statements := []string{
// 完整多级排序索引:媒体库分页与首页预览的 ORDER BY
// (release_date, year, updated_at, created_at, id) DESC 与索引列完全一致,
// LIMIT 分页沿索引顺序直取,免去对整库行做临时 B-tree 排序。
`CREATE INDEX IF NOT EXISTS idx_media_library_recent_active ON media(library_id, release_date DESC, year DESC, updated_at DESC, created_at DESC, id DESC) WHERE deleted_at IS NULL`,
// 计数覆盖索引:首页 CountByLibraries 的 GROUP BY library_id + nsfw 谓词
// 全部落在索引键/部分索引条件上,纯索引扫描即可完成,不回表。
`CREATE INDEX IF NOT EXISTS idx_media_library_nsfw_active ON media(library_id, nsfw) WHERE deleted_at IS NULL`,
// 旧的两键前缀索引被上面的完整排序索引完全覆盖,删除以降低写放大。
`DROP INDEX IF EXISTS idx_media_library_release_active`,
`CREATE INDEX IF NOT EXISTS idx_media_library_created_active ON media(library_id, created_at DESC) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_episode_active ON media(library_id, season_num, episode_num, created_at DESC) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_root_active ON media(library_id, library_root_id) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_series_active ON media(series_id, season_num, episode_num) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_series_active ON media(library_id, series_id, season_num, episode_num) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_tmdb_active ON media(library_id, tm_db_id) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_bangumi_active ON media(library_id, bangumi_id) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_douban_active ON media(library_id, douban_id) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_library_thetvdb_active ON media(library_id, thetvdb_id) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_favorites_user_media_active ON favorites(user_id, media_id) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_playback_histories_user_media_active ON playback_histories(user_id, media_id, watched_at DESC) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_playback_histories_resume_active ON playback_histories(user_id, completed, watched_at DESC) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_play_profiles_user_created_active ON play_profiles(user_id, created_at DESC) WHERE deleted_at IS NULL`,
}
if isSQLite(db) {
statements = append(statements,
`CREATE INDEX IF NOT EXISTS idx_media_title_active ON media(title COLLATE NOCASE) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_original_name_active ON media(original_name COLLATE NOCASE) WHERE deleted_at IS NULL`,
)
} else {
statements = append(statements,
`CREATE INDEX IF NOT EXISTS idx_media_title_active ON media(title) WHERE deleted_at IS NULL`,
`CREATE INDEX IF NOT EXISTS idx_media_original_name_active ON media(original_name) WHERE deleted_at IS NULL`,
)
}
for _, stmt := range statements {
if err := db.Exec(stmt).Error; err != nil {
return err
}
}
return nil
}
func ensureEmbyMountsCompatibility(db *gorm.DB) error {
if !db.Migrator().HasTable(&model.EmbyMount{}) {
return nil
}
if !db.Migrator().HasColumn(&model.EmbyMount{}, "sort_order") {
if err := db.Migrator().AddColumn(&model.EmbyMount{}, "sort_order"); err != nil {
return err
}
}
// 针对已有数据:只给 sort_order=0/NULL 的行按创建时间补号(从现有
// 最大值之后递增),不能整表重排——此前无条件按 created_at 从 0 重新
// 编号,会把用户自定义的顺序覆盖掉。
var zeroCount int64
if err := db.Model(&model.EmbyMount{}).Where("sort_order = 0 OR sort_order IS NULL").Count(&zeroCount).Error; err == nil && zeroCount > 0 {
// max 只统计非 0 行:sort_order=0 与 NULL 同样视为“未分配”,
// 全部为 0 时从 0 开始编号(与迁移前的初始化语义一致)。
var maxOrder int
_ = db.Raw("SELECT COALESCE(MAX(sort_order), -1) FROM emby_mounts WHERE sort_order > 0").Scan(&maxOrder).Error
var mounts []model.EmbyMount
if err := db.Where("sort_order = 0 OR sort_order IS NULL").Order("created_at asc, id asc").Find(&mounts).Error; err == nil {
for i, m := range mounts {
_ = db.Exec("UPDATE emby_mounts SET sort_order = ? WHERE id = ?", maxOrder+1+i, m.ID).Error
}
}
}
return nil
}