db_stat查看cache size大小

電子書《BerkeleyDB-Core-Cxx-GSG.pdf》，在chapter6描述如何查看bdb的cache size。

使用Berkeley DB 4.5.20安裝包中db_stat工具查看。
具體操作如下：

\Oracle\Berkeley DB 4.5.20\bin\db_stat.exe -m -h (bdb環境home目錄)，也就是如下程式碼片段中的envHome

DbEnv myEnv(0);int nRet = 0;try{nRet = myEnv.open(envHome.c_str(), env_flags, 0);}

輸出結果如下：
259KB 260B      Total cache size
1       Number of caches
264KB   Pool individual cache size
0       Maximum memory-mapped file size
0       Maximum open file descriptors
0       Maximum sequential buffer writes
0       Sleep after writing maximum sequential buffers
0       Requested pages mapped into the process' address space
0       Requested pages found in the cache (0%)
1       Requested pages not found in the cache
0       Pages created in the cache
1       Pages read into the cache
0       Pages written from the cache to the backing file
0       Clean pages forced from the cache
0       Dirty pages forced from the cache
0       Dirty pages written by trickle-sync thread
1       Current total page count
1       Current clean page count
0       Current dirty page count
37      Number of hash buckets used for page location
2       Total number of times hash chains searched for a page
0       The longest hash chain searched for a page
0       Total number of hash chain entries checked for page
0       The number of hash bucket locks that required waiting (0%)
0       The maximum number of times any hash bucket lock was waited for (0%)
0       The number of region locks that required waiting (0%)
0       The number of buffers frozen
0       The number of buffers thawed
0       The number of frozen buffers freed
5       The number of page allocations
0       The number of hash buckets examined during allocations
0       The maximum number of hash buckets examined for an allocation
0       The number of pages examined during allocations
0       The max number of pages examined for an allocation
0       Threads waited on page I/O
Pool File: mydb.db
8192    Page size
0       Requested pages mapped into the process' address space
0       Requested pages found in the cache (0%)
1       Requested pages not found in the cache
0       Pages created in the cache
1       Pages read into the cache
0       Pages written from the cache to the backing file
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