DbEnv::log_stat()
Prev | Chapter 8. The DbLsn Handle | Next

## DbEnv::log_stat()

    #include <db_cxx.h>

    int
    DbEnv::log_stat(DB_LOG_STAT **statp, u_int32_t flags);

The `DbEnv::log_stat()` method returns the logging subsystem statistics.

The `DbEnv::log_stat()` method creates a statistical structure of type `DB_LOG_STAT` and copies a pointer to it into a user-specified memory location.

Statistical structures are stored in allocated memory. If application-specific allocation routines have been declared (see DbEnv::set_alloc() for more information), they are used to allocate the memory; otherwise, the standard C library malloc(3) is used. The caller is responsible for deallocating the memory. To deallocate the memory, free the memory reference; references inside the returned memory need not be individually freed.

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.

- 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_size;

  The log file size.

- uintmax_t st_record;

  The number of records written to this 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.

- uintmax_t st_wcount;

  The number of times the log has been written to disk.

- uintmax_t st_wcount_fill;

  The number of times the log has been written to disk because the in-memory log record cache filled up.

- uintmax_t st_rcount;

  The number of times the log has been read from disk.

- uintmax_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_disk_file;

  The log file number of the last record known to be on disk.

- u_int32_t st_disk_offset;

  The byte offset of the last record known to be on disk.

- u_int32_t st_maxcommitperflush;

  The maximum number of commits contained in a single log flush.

- u_int32_t st_mincommitperflush;

  The minimum number of commits contained in a single log flush that contained a commit.

- roff_t st_regsize;

  The size of the log region, in bytes.

- uintmax_t st_region_wait;

  The number of times that a thread of control was forced to wait before obtaining the log region mutex.

- uintmax_t st_region_nowait;

  The number of times that a thread of control was able to obtain the log region mutex without waiting.

The `DbEnv::log_stat()` method may not be called before the DbEnv::open() method is called.

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.

### Parameters

#### statp

The statp parameter references memory into which a pointer to the allocated statistics structure is copied.

#### flags

The flags parameter must be set to 0 or the following value:

- `DB_STAT_CLEAR`

  Reset statistics after returning their values.

### Errors

The `DbEnv::log_stat()` method may fail and throw a DbException exception, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

#### EINVAL

An invalid flag value or parameter was specified.

### Class

DbEnv, DbLogc, DbLsn

### See Also

Logging Subsystem and Related Methods

Prev | Up | Next
DbEnv::log_set_config() | Home | DbEnv::log_stat_print()