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[td-1569]

This commit is contained in:
Haojun Liao 2020-10-26 14:42:56 +08:00
parent 5b23931687
commit 00cc76aed9
1 changed files with 7 additions and 2 deletions
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9
src/util/src/tcache.c
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@ -335,7 +335,7 @@ void *taosCacheTransfer(SCacheObj *pCacheObj, void **data) {
} }
void taosCacheRelease(SCacheObj *pCacheObj, void **data, bool _remove) { void taosCacheRelease(SCacheObj *pCacheObj, void **data, bool _remove) {
if (pCacheObj == NULL || taosHashGetSize(pCacheObj->pHashTable) + pCacheObj->numOfElemsInTrash == 0) { if (pCacheObj == NULL) {
return; return;
} }
@ -343,7 +343,12 @@ void taosCacheRelease(SCacheObj *pCacheObj, void **data, bool _remove) {
uError("cache:%s, NULL data to release", pCacheObj->name); uError("cache:%s, NULL data to release", pCacheObj->name);
return; return;
} }
// The operation of removal from hash table and addition to trashcan is not an atomic operation,
// therefore the check for the empty of both the hash table and the trashcan has a race condition.
// It happens when there is only one object in the cache, and two threads which has referenced this object
// start to free the it simultaneously. [TD-1569]
size_t offset = offsetof(SCacheDataNode, data); size_t offset = offsetof(SCacheDataNode, data);
SCacheDataNode *pNode = (SCacheDataNode *)((char *)(*data) - offset); SCacheDataNode *pNode = (SCacheDataNode *)((char *)(*data) - offset);