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Type:
Task
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Resolution: Done
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None
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Affects Version/s: None
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Component/s: None
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None
If a thread is updating its session flags, this code in __lsm_tree_close can race and fail to set the WT_SESSION_SCHEMA_LOCKED flag, so the thread blocks forever instead of completing its operations.
Consider either switching to atomic flags, or (better) adding a field to the session structure that can be set and cleared atomically for this case (and checked inside WT_WITH_SCHEMA_LOCK).
/*
* Signal all threads to wake them up, then wait for them to
* exit.
*
* !!!
* If we have the schema lock, have the LSM worker sessions
* inherit the flag before we do anything. The thread may
* already be waiting for the schema lock, but the loop in the
* WT_WITH_SCHEMA_LOCK macro takes care of that.
*/
if (F_ISSET(S2C(session), WT_CONN_LSM_MERGE))
for (i = 0; i < lsm_tree->merge_threads; i++) {
F_SET(lsm_tree->worker_sessions[i],
F_ISSET(session, WT_SESSION_SCHEMA_LOCKED));