handle cache write/reade concurrent problem

source/libs/index/inc/index_cache.h

@@ -30,14 +30,18 @@
 extern "C" {
 #endif
 
+typedef struct MemTable {
+  T_REF_DECLARE()
+  SSkipList* mem;
+} MemTable;
 typedef struct IndexCache {
   T_REF_DECLARE()
-  SSkipList *mem, *imm;
-  SIndex*    index;
-  char*      colName;
-  int32_t    version;
-  int32_t    nTerm;
-  int8_t     type;
+  MemTable *mem, *imm;
+  SIndex*   index;
+  char*     colName;
+  int32_t   version;
+  int32_t   nTerm;
+  int8_t    type;
 
   pthread_mutex_t mtx;
 } IndexCache;

source/libs/index/src/index_cache.c

@@ -25,44 +25,20 @@
 //#define CACHE_KEY_LEN(p) \
 //  (sizeof(int32_t) + sizeof(uint16_t) + sizeof(p->colType) + sizeof(p->nColVal) + p->nColVal + sizeof(uint64_t) + sizeof(p->operType))
 
-static void cacheTermDestroy(CacheTerm* ct) {
-  if (ct == NULL) { return; }
+void indexMemRef(MemTable* tbl);
+void indexMemUnRef(MemTable* tbl);
 
-  free(ct->colVal);
-  free(ct);
-}
-static char* getIndexKey(const void* pData) {
-  CacheTerm* p = (CacheTerm*)pData;
-  return (char*)p;
-}
+void indexCacheRef(IndexCache* cache);
+void indexCacheUnRef(IndexCache* cache);
 
-static int32_t compareKey(const void* l, const void* r) {
-  CacheTerm* lt = (CacheTerm*)l;
-  CacheTerm* rt = (CacheTerm*)r;
+static void      cacheTermDestroy(CacheTerm* ct);
+static char*     getIndexKey(const void* pData);
+static int32_t   compareKey(const void* l, const void* r);
+static MemTable* indexInternalCacheCreate(int8_t type);
 
-  // compare colVal
-  int i, j;
-  for (i = 0, j = 0; i < lt->nColVal && j < rt->nColVal; i++, j++) {
-    if (lt->colVal[i] == rt->colVal[j]) {
-      continue;
-    } else {
-      return lt->colVal[i] < rt->colVal[j] ? -1 : 1;
-    }
-  }
-  if (i < lt->nColVal) {
-    return 1;
-  } else if (j < rt->nColVal) {
-    return -1;
-  }
-  // compare version
-  return rt->version - lt->version;
-}
-
-static SSkipList* indexInternalCacheCreate(int8_t type) {
-  if (type == TSDB_DATA_TYPE_BINARY) {
-    return tSkipListCreate(MAX_SKIP_LIST_LEVEL, type, MAX_INDEX_KEY_LEN, compareKey, SL_ALLOW_DUP_KEY, getIndexKey);
-  }
-}
+static void          doMergeWork(SSchedMsg* msg);
+static bool          indexCacheIteratorNext(Iterate* itera);
+static IterateValue* indexCacheIteratorGetValue(Iterate* iter);
 
 IndexCache* indexCacheCreate(SIndex* idx, const char* colName, int8_t type) {
   IndexCache* cache = calloc(1, sizeof(IndexCache));
@@ -83,7 +59,15 @@ IndexCache* indexCacheCreate(SIndex* idx, const char* colName, int8_t type) {
   return cache;
 }
 void indexCacheDebug(IndexCache* cache) {
-  SSkipListIterator* iter = tSkipListCreateIter(cache->mem);
+  MemTable* tbl = NULL;
+
+  pthread_mutex_lock(&cache->mtx);
+  tbl = cache->mem;
+  indexMemRef(tbl);
+  pthread_mutex_unlock(&cache->mtx);
+
+  SSkipList*         slt = tbl->mem;
+  SSkipListIterator* iter = tSkipListCreateIter(slt);
   while (tSkipListIterNext(iter)) {
     SSkipListNode* node = tSkipListIterGet(iter);
     CacheTerm*     ct = (CacheTerm*)SL_GET_NODE_DATA(node);
@@ -93,6 +77,8 @@ void indexCacheDebug(IndexCache* cache) {
     }
   }
   tSkipListDestroyIter(iter);
+
+  indexMemUnRef(tbl);
 }
 
 void indexCacheDestroySkiplist(SSkipList* slt) {
@@ -103,60 +89,33 @@ void indexCacheDestroySkiplist(SSkipList* slt) {
     if (ct != NULL) {}
   }
   tSkipListDestroyIter(iter);
+  tSkipListDestroy(slt);
 }
 void indexCacheDestroyImm(IndexCache* cache) {
+  MemTable* tbl = NULL;
   pthread_mutex_lock(&cache->mtx);
-  SSkipList* timm = (SSkipList*)cache->imm;
+  tbl = cache->imm;
   cache->imm = NULL;  // or throw int bg thread
   pthread_mutex_unlock(&cache->mtx);
-
-  indexCacheDestroySkiplist(timm);
+  indexMemUnRef(tbl);
 }
 void indexCacheDestroy(void* cache) {
   IndexCache* pCache = cache;
   if (pCache == NULL) { return; }
-  tSkipListDestroy(pCache->mem);
-  tSkipListDestroy(pCache->imm);
+  indexMemUnRef(pCache->mem);
+  indexMemUnRef(pCache->imm);
   free(pCache->colName);
 
   free(pCache);
 }
 
-static void doMergeWork(SSchedMsg* msg) {
-  IndexCache* pCache = msg->ahandle;
-  SIndex*     sidx = (SIndex*)pCache->index;
-  indexFlushCacheTFile(sidx, pCache);
-}
-static bool indexCacheIteratorNext(Iterate* itera) {
-  SSkipListIterator* iter = itera->iter;
-  if (iter == NULL) { return false; }
-
-  IterateValue* iv = &itera->val;
-  iterateValueDestroy(iv, false);
-
-  bool next = tSkipListIterNext(iter);
-  if (next) {
-    SSkipListNode* node = tSkipListIterGet(iter);
-    CacheTerm*     ct = (CacheTerm*)SL_GET_NODE_DATA(node);
-
-    iv->type = ct->operaType;
-    iv->colVal = ct->colVal;
-
-    taosArrayPush(iv->val, &ct->uid);
-  }
-
-  return next;
-}
-
-static IterateValue* indexCacheIteratorGetValue(Iterate* iter) {
-  return &iter->val;
-}
 Iterate* indexCacheIteratorCreate(IndexCache* cache) {
   Iterate* iiter = calloc(1, sizeof(Iterate));
   if (iiter == NULL) { return NULL; }
 
+  MemTable* tbl = cache->imm;
   iiter->val.val = taosArrayInit(1, sizeof(uint64_t));
-  iiter->iter = cache->imm != NULL ? tSkipListCreateIter(cache->imm) : NULL;
+  iiter->iter = tbl != NULL ? tSkipListCreateIter(tbl->mem) : NULL;
   iiter->next = indexCacheIteratorNext;
   iiter->getValue = indexCacheIteratorGetValue;
 
@@ -220,8 +179,13 @@ int indexCachePut(void* cache, SIndexTerm* term, uint64_t uid) {
 
   // ugly code, refactor later
   pthread_mutex_lock(&pCache->mtx);
+
   indexCacheMakeRoomForWrite(pCache);
-  tSkipListPut(pCache->mem, (char*)ct);
+  MemTable* tbl = pCache->mem;
+  indexMemRef(tbl);
+  tSkipListPut(tbl->mem, (char*)ct);
+  indexMemUnRef(tbl);
+
   pthread_mutex_unlock(&pCache->mtx);
 
   indexCacheUnRef(pCache);
@@ -238,6 +202,14 @@ int indexCacheSearch(void* cache, SIndexTermQuery* query, SArray* result, STermV
   SIndexTerm*     term = query->term;
   EIndexQueryType qtype = query->qType;
 
+  MemTable *mem = NULL, *imm = NULL;
+  pthread_mutex_lock(&pCache->mtx);
+  mem = pCache->mem;
+  imm = pCache->imm;
+  indexMemRef(mem);
+  indexMemRef(imm);
+  pthread_mutex_unlock(&pCache->mtx);
+
   CacheTerm* ct = calloc(1, sizeof(CacheTerm));
   if (ct == NULL) { return -1; }
   ct->nColVal = term->nColVal;
@@ -247,7 +219,7 @@ int indexCacheSearch(void* cache, SIndexTermQuery* query, SArray* result, STermV
 
   char* key = getIndexKey(ct);
   // TODO handle multi situation later, and refactor
-  SSkipListIterator* iter = tSkipListCreateIterFromVal(pCache->mem, key, TSDB_DATA_TYPE_BINARY, TSDB_ORDER_ASC);
+  SSkipListIterator* iter = tSkipListCreateIterFromVal(mem->mem, key, TSDB_DATA_TYPE_BINARY, TSDB_ORDER_ASC);
   while (tSkipListIterNext(iter)) {
     SSkipListNode* node = tSkipListIterGet(iter);
     if (node != NULL) {
@@ -279,14 +251,108 @@ int indexCacheSearch(void* cache, SIndexTermQuery* query, SArray* result, STermV
   } else if (qtype == QUERY_REGEX) {
     //
   }
+  indexMemUnRef(mem);
+  indexMemUnRef(imm);
   return 0;
 }
 
 void indexCacheRef(IndexCache* cache) {
+  if (cache == NULL) { return; }
+
   int ref = T_REF_INC(cache);
   UNUSED(ref);
 }
 void indexCacheUnRef(IndexCache* cache) {
+  if (cache == NULL) { return; }
+
   int ref = T_REF_DEC(cache);
   if (ref == 0) { indexCacheDestroy(cache); }
 }
+
+void indexMemRef(MemTable* tbl) {
+  if (tbl == NULL) { return; }
+  int ref = T_REF_INC(tbl);
+  UNUSED(ref);
+}
+void indexMemUnRef(MemTable* tbl) {
+  if (tbl == NULL) { return; }
+
+  int ref = T_REF_DEC(tbl);
+  if (ref == 0) {
+    SSkipList* slt = tbl->mem;
+    indexCacheDestroySkiplist(slt);
+    free(tbl);
+  }
+}
+
+static void cacheTermDestroy(CacheTerm* ct) {
+  if (ct == NULL) { return; }
+
+  free(ct->colVal);
+  free(ct);
+}
+static char* getIndexKey(const void* pData) {
+  CacheTerm* p = (CacheTerm*)pData;
+  return (char*)p;
+}
+
+static int32_t compareKey(const void* l, const void* r) {
+  CacheTerm* lt = (CacheTerm*)l;
+  CacheTerm* rt = (CacheTerm*)r;
+
+  // compare colVal
+  int i, j;
+  for (i = 0, j = 0; i < lt->nColVal && j < rt->nColVal; i++, j++) {
+    if (lt->colVal[i] == rt->colVal[j]) {
+      continue;
+    } else {
+      return lt->colVal[i] < rt->colVal[j] ? -1 : 1;
+    }
+  }
+  if (i < lt->nColVal) {
+    return 1;
+  } else if (j < rt->nColVal) {
+    return -1;
+  }
+  // compare version
+  return rt->version - lt->version;
+}
+
+static MemTable* indexInternalCacheCreate(int8_t type) {
+  MemTable* tbl = calloc(1, sizeof(MemTable));
+  indexMemRef(tbl);
+  if (type == TSDB_DATA_TYPE_BINARY) {
+    tbl->mem = tSkipListCreate(MAX_SKIP_LIST_LEVEL, type, MAX_INDEX_KEY_LEN, compareKey, SL_ALLOW_DUP_KEY, getIndexKey);
+  }
+  return tbl;
+}
+
+static void doMergeWork(SSchedMsg* msg) {
+  IndexCache* pCache = msg->ahandle;
+  SIndex*     sidx = (SIndex*)pCache->index;
+  indexFlushCacheTFile(sidx, pCache);
+}
+static bool indexCacheIteratorNext(Iterate* itera) {
+  SSkipListIterator* iter = itera->iter;
+  if (iter == NULL) { return false; }
+
+  IterateValue* iv = &itera->val;
+  iterateValueDestroy(iv, false);
+
+  bool next = tSkipListIterNext(iter);
+  if (next) {
+    SSkipListNode* node = tSkipListIterGet(iter);
+    CacheTerm*     ct = (CacheTerm*)SL_GET_NODE_DATA(node);
+
+    iv->type = ct->operaType;
+    iv->colVal = ct->colVal;
+
+    taosArrayPush(iv->val, &ct->uid);
+  }
+
+  return next;
+}
+
+static IterateValue* indexCacheIteratorGetValue(Iterate* iter) {
+  return &iter->val;
+}