mirror of
https://github.com/isar/libmdbx.git
synced 2025-01-02 04:34:12 +08:00
mdbx: rework/simplify mdbx_env_sync_internal().
This commit is contained in:
Леонид Юрьев (Leonid Yuriev)
parent
8ef8733ddc
commit
da855b13a3
192
src/core.c
192
src/core.c
@ -6977,119 +6977,123 @@ fail:
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__cold static int mdbx_env_sync_internal(MDBX_env *env, bool force,
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bool nonblock) {
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unsigned flags = env->me_flags & ~MDBX_NOMETASYNC;
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if (unlikely(flags & (MDBX_RDONLY | MDBX_FATAL_ERROR)))
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return MDBX_EACCESS;
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bool locked = false;
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int rc = MDBX_RESULT_TRUE /* means "nothing to sync" */;
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bool need_unlock = false;
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if (nonblock &&
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atomic_load32(&env->me_lck->mti_unsynced_pages, mo_AcquireRelease) == 0)
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goto fastpath;
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const bool outside_txn = (env->me_txn0->mt_owner != mdbx_thread_self());
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if (outside_txn) {
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int err = mdbx_txn_lock(env, nonblock);
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if (unlikely(err != MDBX_SUCCESS))
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return err;
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need_unlock = true;
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retry:;
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unsigned flags = env->me_flags & ~MDBX_NOMETASYNC;
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if (unlikely(flags & (MDBX_RDONLY | MDBX_FATAL_ERROR))) {
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rc = MDBX_EACCESS;
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goto bailout;
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}
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const MDBX_meta *head = mdbx_meta_head(env);
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pgno_t unsynced_pages =
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const pgno_t unsynced_pages =
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atomic_load32(&env->me_lck->mti_unsynced_pages, mo_Relaxed);
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if (!META_IS_STEADY(head) || unsynced_pages) {
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const pgno_t autosync_threshold =
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atomic_load32(&env->me_lck->mti_autosync_threshold, mo_Relaxed);
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const uint64_t autosync_period =
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atomic_load64(&env->me_lck->mti_autosync_period, mo_Relaxed);
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if (force || (autosync_threshold && unsynced_pages >= autosync_threshold) ||
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(autosync_period &&
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mdbx_osal_monotime() -
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atomic_load64(&env->me_lck->mti_sync_timestamp, mo_Relaxed) >=
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autosync_period))
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flags &= MDBX_WRITEMAP /* clear flags for full steady sync */;
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const MDBX_meta *head = mdbx_meta_head(env);
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const txnid_t head_txnid = mdbx_meta_txnid_fluid(env, head);
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const uint32_t synched_meta_txnid_u32 =
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atomic_load32(&env->me_lck->mti_meta_sync_txnid, mo_Relaxed);
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if (unsynced_pages == 0 && synched_meta_txnid_u32 == (uint32_t)head_txnid &&
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META_IS_STEADY(head))
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goto bailout;
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if (outside_txn) {
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const pgno_t autosync_threshold =
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atomic_load32(&env->me_lck->mti_autosync_threshold, mo_Relaxed);
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const uint64_t autosync_period =
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atomic_load64(&env->me_lck->mti_autosync_period, mo_Relaxed);
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if (force || (autosync_threshold && unsynced_pages >= autosync_threshold) ||
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(autosync_period &&
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mdbx_osal_monotime() -
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atomic_load64(&env->me_lck->mti_sync_timestamp, mo_Relaxed) >=
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autosync_period))
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flags &= MDBX_WRITEMAP /* clear flags for full steady sync */;
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const bool inside_txn = (env->me_txn0->mt_owner == mdbx_thread_self());
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if (!inside_txn) {
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if (!locked) {
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int err;
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unsigned wops = 0;
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/* pre-sync to avoid latency for writer */
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if (unsynced_pages > /* FIXME: define threshold */ 16 &&
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(flags & MDBX_SAFE_NOSYNC) == 0) {
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mdbx_assert(env, ((flags ^ env->me_flags) & MDBX_WRITEMAP) == 0);
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const size_t usedbytes = pgno_align2os_bytes(env, head->mm_geo.next);
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if (flags & MDBX_WRITEMAP) {
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/* Acquire guard to avoid collision with remap */
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#if defined(_WIN32) || defined(_WIN64)
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mdbx_srwlock_AcquireShared(&env->me_remap_guard);
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#else
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err = mdbx_fastmutex_acquire(&env->me_remap_guard);
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if (unlikely(err != MDBX_SUCCESS))
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return err;
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#endif
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const size_t usedbytes = pgno_align2os_bytes(env, head->mm_geo.next);
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err = mdbx_msync(&env->me_dxb_mmap, 0, usedbytes, MDBX_SYNC_DATA);
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#if defined(_WIN32) || defined(_WIN64)
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mdbx_srwlock_ReleaseShared(&env->me_remap_guard);
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#else
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int unlock_err = mdbx_fastmutex_release(&env->me_remap_guard);
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if (unlikely(unlock_err != MDBX_SUCCESS) && err == MDBX_SUCCESS)
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err = unlock_err;
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#endif
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} else
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err = mdbx_fsync(env->me_lazy_fd, MDBX_SYNC_DATA);
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#if MDBX_ENABLE_PGOP_STAT
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env->me_lck->mti_pgop_stat.wops.weak += 1;
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#endif /* MDBX_ENABLE_PGOP_STAT */
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mdbx_txn_unlock(env);
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/* LY: pre-sync without holding lock to reduce latency for writer(s) */
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int err =
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(flags & MDBX_WRITEMAP)
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? mdbx_msync(&env->me_dxb_mmap, 0, usedbytes, MDBX_SYNC_DATA)
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: mdbx_fsync(env->me_lazy_fd, MDBX_SYNC_DATA);
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if (unlikely(err != MDBX_SUCCESS))
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return err;
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err = mdbx_txn_lock(env, nonblock);
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if (unlikely(err != MDBX_SUCCESS))
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return err;
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/* LY: head and unsynced_pages may be changed. */
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head = mdbx_meta_head(env);
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unsynced_pages =
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atomic_load32(&env->me_lck->mti_unsynced_pages, mo_Relaxed);
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/* pre-sync done */
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wops = 1;
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rc = MDBX_SUCCESS /* means "some data was synced" */;
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}
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env->me_txn0->mt_txnid = meta_txnid(env, head, false);
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mdbx_find_oldest(env->me_txn0);
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rc = MDBX_RESULT_FALSE /* means "some data was synced" */;
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}
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if (!META_IS_STEADY(head) ||
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((flags & MDBX_SAFE_NOSYNC) == 0 && unsynced_pages)) {
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mdbx_debug("meta-head %" PRIaPGNO ", %s, sync_pending %" PRIaPGNO,
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data_page(head)->mp_pgno, mdbx_durable_str(head),
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unsynced_pages);
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MDBX_meta meta = *head;
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int err = mdbx_sync_locked(env, flags | MDBX_SHRINK_ALLOWED, &meta);
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if (unlikely(err != MDBX_SUCCESS)) {
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if (need_unlock)
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mdbx_txn_unlock(env);
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err = mdbx_txn_lock(env, nonblock);
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if (unlikely(err != MDBX_SUCCESS))
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return err;
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}
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rc = MDBX_RESULT_FALSE /* means "some data was synced" */;
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locked = true;
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#if MDBX_ENABLE_PGOP_STAT
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env->me_lck->mti_pgop_stat.wops.weak += wops;
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#endif /* MDBX_ENABLE_PGOP_STAT */
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goto retry;
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}
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env->me_txn0->mt_txnid = head_txnid;
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mdbx_assert(env, head_txnid == meta_txnid(env, head, false));
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mdbx_assert(env, head_txnid == mdbx_recent_committed_txnid(env));
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mdbx_find_oldest(env->me_txn0);
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}
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mdbx_assert(env, inside_txn || locked);
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if (!META_IS_STEADY(head) ||
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((flags & MDBX_SAFE_NOSYNC) == 0 && unsynced_pages)) {
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mdbx_debug("meta-head %" PRIaPGNO ", %s, sync_pending %" PRIaPGNO,
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data_page(head)->mp_pgno, mdbx_durable_str(head),
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unsynced_pages);
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MDBX_meta meta = *head;
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rc = mdbx_sync_locked(env, flags | MDBX_SHRINK_ALLOWED, &meta);
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if (unlikely(rc != MDBX_SUCCESS))
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goto bailout;
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}
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fastpath:
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/* LY: sync meta-pages if MDBX_NOMETASYNC enabled
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* and someone was not synced above. */
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if (rc == MDBX_RESULT_TRUE && (env->me_flags & MDBX_NOMETASYNC) != 0) {
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const txnid_t head_txnid = mdbx_recent_committed_txnid(env);
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if (atomic_load32(&env->me_lck->mti_meta_sync_txnid, mo_Relaxed) !=
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(uint32_t)head_txnid) {
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if (atomic_load32(&env->me_lck->mti_meta_sync_txnid, mo_Relaxed) !=
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(uint32_t)head_txnid) {
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#if MDBX_ENABLE_PGOP_STAT
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if (need_unlock)
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env->me_lck->mti_pgop_stat.wops.weak += 1;
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#if MDBX_64BIT_ATOMIC
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else {
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MDBX_atomic_uint64_t *wops = &env->me_lck->mti_pgop_stat.wops;
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while (unlikely(!atomic_cas64(wops, wops->weak, wops->weak + 1)))
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atomic_yield();
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}
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#else
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/* loose the env->me_lck->mti_pgop_stat.wops.weak increment */
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#endif /* MDBX_64BIT_ATOMIC */
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env->me_lck->mti_pgop_stat.wops.weak += 1;
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#endif /* MDBX_ENABLE_PGOP_STAT */
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rc = (flags & MDBX_WRITEMAP)
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? mdbx_msync(&env->me_dxb_mmap, 0,
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pgno_align2os_bytes(env, NUM_METAS),
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MDBX_SYNC_DATA | MDBX_SYNC_IODQ)
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: mdbx_fsync(env->me_lazy_fd, MDBX_SYNC_DATA | MDBX_SYNC_IODQ);
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if (likely(rc == MDBX_SUCCESS))
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atomic_store32(&env->me_lck->mti_meta_sync_txnid, (uint32_t)head_txnid,
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mo_Relaxed);
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}
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rc = (flags & MDBX_WRITEMAP)
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? mdbx_msync(&env->me_dxb_mmap, 0,
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pgno_align2os_bytes(env, NUM_METAS),
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MDBX_SYNC_DATA | MDBX_SYNC_IODQ)
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: mdbx_fsync(env->me_lazy_fd, MDBX_SYNC_DATA | MDBX_SYNC_IODQ);
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if (likely(rc == MDBX_SUCCESS))
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atomic_store32(&env->me_lck->mti_meta_sync_txnid, (uint32_t)head_txnid,
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mo_Relaxed);
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}
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if (need_unlock)
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bailout:
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if (locked)
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mdbx_txn_unlock(env);
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return rc;
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}
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@ -10911,11 +10915,9 @@ static int mdbx_sync_locked(MDBX_env *env, unsigned flags,
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goto undo;
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}
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}
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if (flags & MDBX_NOMETASYNC)
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env->me_lck->mti_unsynced_pages.weak += 1;
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else
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env->me_lck->mti_meta_sync_txnid.weak =
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(uint32_t)unaligned_peek_u64(4, pending->mm_txnid_a);
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env->me_lck->mti_meta_sync_txnid.weak =
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(uint32_t)unaligned_peek_u64(4, pending->mm_txnid_a) -
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((flags & MDBX_NOMETASYNC) ? UINT32_MAX / 3 : 0);
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/* LY: shrink datafile if needed */
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if (unlikely(shrink)) {
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@ -19471,7 +19473,7 @@ __cold static int fetch_envinfo_ex(const MDBX_env *env, const MDBX_txn *txn,
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const pgno_t unsynced_pages =
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atomic_load32(&env->me_lck->mti_unsynced_pages, mo_Relaxed) +
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(atomic_load32(&env->me_lck->mti_meta_sync_txnid, mo_Relaxed) !=
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(uint32_t)arg->mi_last_pgno);
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(uint32_t)arg->mi_recent_txnid);
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arg->mi_mapsize = env->me_dxb_mmap.limit;
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