Berkeley DB: DbEnv::log_stat
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# DbEnv::log_stat |

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###

    #include <db_cxx.h>

    int
    DbEnv::log_stat(DB_LOG_STAT **spp, void *(*db_malloc)(size_t));

# Description

The DbEnv::log_stat method creates a statistical structure and copies a pointer to it into a user-specified memory location.

Statistical structures are created in allocated memory. If db_malloc is non-NULL, it is called to allocate the memory, otherwise, the library function malloc(3) is used. The function db_malloc must match the calling conventions of the malloc(3) library routine. Regardless, the caller is responsible for deallocating the returned memory. To deallocate returned memory, free the returned memory reference, references inside the returned memory do not need to be individually freed.

The log region statistics are stored in a structure of type DB_LOG_STAT. The following DB_LOG_STAT fields will be filled in:

u_int32_t st_magic;
  The magic number that identifies a file as a log file.
u_int32_t st_version;
  The version of the log file type.
u_int32_t st_regsize;
  The size of the region.
int st_mode;
  The mode of any created log files.
u_int32_t st_lg_bsize;
  The in-memory log record cache size.
u_int32_t st_lg_max;
  The maximum size of any individual file comprising the log.
u_int32_t st_w_mbytes;
  The number of megabytes written to this log.
u_int32_t st_w_bytes;
  The number of bytes over and above st_w_mbytes written to this log.
u_int32_t st_wc_mbytes;
  The number of megabytes written to this log since the last checkpoint.
u_int32_t st_wc_bytes;
  The number of bytes over and above st_wc_mbytes written to this log since the last checkpoint.
u_int32_t st_wcount;
  The number of times the log has been written to disk.
u_int32_t st_wcount_fill;
  The number of times the log has been written to disk because the in-memory log record cache filled up.
u_int32_t st_scount;
  The number of times the log has been flushed to disk.
u_int32_t st_cur_file;
  The current log file number.
u_int32_t st_cur_offset;
  The byte offset in the current log file.
u_int32_t st_region_wait;
  The number of times that a thread of control was forced to wait before obtaining the region lock.
u_int32_t st_region_nowait;
  The number of times that a thread of control was able to obtain the region lock without waiting.

The DbEnv::log_stat method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

# Errors

If a fatal error occurs in Berkeley DB, the DbEnv::log_stat method will fail and either return DB_RUNRECOVERY or throw an exception encapsulating DB_RUNRECOVERY, at which point all subsequent database calls will fail in the same way.

In addition, the DbEnv::log_stat method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.

### Class

DbEnv

# See Also

DbEnv::set_lg_bsize, DbEnv::set_lg_max, DbEnv::log_archive, DbEnv::log_compare, DbEnv::log_file, DbEnv::log_flush, DbEnv::log_get, DbEnv::log_put, DbEnv::log_register, DbEnv::log_stat and DbEnv::log_unregister.`

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