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Help to recover from corrupted levelqueue (#24912)

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gitea.com experienced the corrupted LevelQueue bug again.

I think the problem is clear now: if the keys in LevelDB went
out-of-sync, the LevelQueue itself doesn't have the ability to recover,
eg:

* LevelQueue.Len() reports 100
* LevelQueue.LPop() reports ErrNotFound = errors.New("no key found")

So it needs to dive into the LevelDB to remove all keys to recover the
corrupted LevelQueue.

More comments are in TestCorruptedLevelQueue.
This commit is contained in:
wxiaoguang 2023-05-29 10:52:32 +08:00 • committed by GitHub
parent 8faf9465b3
commit 84c8ab9fd1
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 162 additions and 55 deletions
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58
modules/queue/base_levelqueue_unique.go
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@ -6,18 +6,21 @@ package queue
import (
"context"
"sync"
"unsafe"
"sync/atomic"
"code.gitea.io/gitea/modules/nosql"
"code.gitea.io/gitea/modules/queue/lqinternal"
"gitea.com/lunny/levelqueue"
"github.com/syndtr/goleveldb/leveldb"
)
type baseLevelQueueUnique struct {
internal *levelqueue.UniqueQueue
conn string
cfg *BaseConfig
internal atomic.Pointer[levelqueue.UniqueQueue]
conn string
cfg *BaseConfig
db *leveldb.DB
mu sync.Mutex // the levelqueue.UniqueQueue is not thread-safe, there is no mutex protecting the underlying queue&set together
}
@ -29,39 +32,42 @@ func newBaseLevelQueueUnique(cfg *BaseConfig) (baseQueue, error) {
if err != nil {
return nil, err
}
q := &baseLevelQueueUnique{conn: conn, cfg: cfg}
q.internal, err = levelqueue.NewUniqueQueue(db, []byte(cfg.QueueFullName), []byte(cfg.SetFullName), false)
q := &baseLevelQueueUnique{conn: conn, cfg: cfg, db: db}
lq, err := levelqueue.NewUniqueQueue(db, []byte(cfg.QueueFullName), []byte(cfg.SetFullName), false)
if err != nil {
return nil, err
}
q.internal.Store(lq)
return q, nil
}
func (q *baseLevelQueueUnique) PushItem(ctx context.Context, data []byte) error {
return baseLevelQueueCommon(q.cfg, q.internal, &q.mu).PushItem(ctx, data)
c := baseLevelQueueCommon(q.cfg, &q.mu, func() baseLevelQueuePushPoper { return q.internal.Load() })
return c.PushItem(ctx, data)
}
func (q *baseLevelQueueUnique) PopItem(ctx context.Context) ([]byte, error) {
return baseLevelQueueCommon(q.cfg, q.internal, &q.mu).PopItem(ctx)
c := baseLevelQueueCommon(q.cfg, &q.mu, func() baseLevelQueuePushPoper { return q.internal.Load() })
return c.PopItem(ctx)
}
func (q *baseLevelQueueUnique) HasItem(ctx context.Context, data []byte) (bool, error) {
q.mu.Lock()
defer q.mu.Unlock()
return q.internal.Has(data)
return q.internal.Load().Has(data)
}
func (q *baseLevelQueueUnique) Len(ctx context.Context) (int, error) {
q.mu.Lock()
defer q.mu.Unlock()
return int(q.internal.Len()), nil
return int(q.internal.Load().Len()), nil
}
func (q *baseLevelQueueUnique) Close() error {
q.mu.Lock()
defer q.mu.Unlock()
err := q.internal.Close()
err := q.internal.Load().Close()
q.db = nil // the db is not managed by us, it's managed by the nosql manager
_ = nosql.GetManager().CloseLevelDB(q.conn)
return err
}
@ -69,28 +75,14 @@ func (q *baseLevelQueueUnique) Close() error {
func (q *baseLevelQueueUnique) RemoveAll(ctx context.Context) error {
q.mu.Lock()
defer q.mu.Unlock()
type levelUniqueQueue struct {
q *levelqueue.Queue
set *levelqueue.Set
db *leveldb.DB
}
lq := (*levelUniqueQueue)(unsafe.Pointer(q.internal))
for lq.q.Len() > 0 {
if _, err := lq.q.LPop(); err != nil {
return err
}
}
// the "set" must be cleared after the "list" because there is no transaction.
// it's better to have duplicate items than losing items.
members, err := lq.set.Members()
lqinternal.RemoveLevelQueueKeys(q.db, []byte(q.cfg.QueueFullName))
lqinternal.RemoveLevelQueueKeys(q.db, []byte(q.cfg.SetFullName))
lq, err := levelqueue.NewUniqueQueue(q.db, []byte(q.cfg.QueueFullName), []byte(q.cfg.SetFullName), false)
if err != nil {
return err // seriously corrupted
}
for _, v := range members {
_, _ = lq.set.Remove(v)
return err
}
old := q.internal.Load()
q.internal.Store(lq)
_ = old.Close() // Not ideal for concurrency. Luckily, the levelqueue only sets its db=nil because it doesn't manage the db, so far so good
return nil
}