Berkeley DB: DbEnv::log_stat
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,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 **statp, u_int32_t flags);

    int
    DbEnv::log_stat_print(u_int32_t flags);

### Description: DbEnv::log_stat

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.
u_int32_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.
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_rcount;
  The number of times the log has been read from disk.
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_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.
u_int32_t st_region_wait;
  The number of times that a thread of control was forced to wait before obtaining the log region mutex.
u_int32_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 has been 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

flags
  The flags parameter must be set to 0 or the following value:
  DB_STAT_CLEAR
    Reset statistics after returning their values.
statp
  The statp parameter references memory into which a pointer to the allocated statistics structure is copied.

### Errors

The DbEnv::log_stat method may fail and throw DbException, 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.

### Description: DbEnv::log_stat_print

The DbEnv::log_stat_print method displays the logging subsystem statistical information, as described for the DbEnv::log_stat method. The information is printed to a specified output channel (see the DbEnv::set_msgfile method for more information), or passed to an application callback function (see the DbEnv::set_msgcall method for more information).

The DbEnv::log_stat_print method may not be called before the DbEnv::open method has been called.

The DbEnv::log_stat_print 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

flags
  The flags parameter must be set to 0 or by bitwise inclusively OR'ing together one or more of the following values:
  DB_STAT_ALL
    Display all available information.
  DB_STAT_CLEAR
    Reset statistics after displaying their values.

### Class

DbEnv, DbLogc, DbLsn

### See Also

Logging Subsystem and Related Methods`

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