Berkeley DB: DB_ENV->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++

# DB_ENV->log_stat |

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    #include <db.h>

    int
    DB_ENV->log_stat(DB_ENV *env, DB_LOG_STAT **spp, u_int32_t flags);

# Description

The DB_ENV->log_stat function creates a statistical structure and copies a pointer to it into a user-specified memory location.

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

DB_STAT_CLEAR
  Reset statistics after returning their values.

Statistical structures are created in allocated memory. If application-specific allocation routines have been declared (see DB_ENV->set_alloc for more information), they are used to allocate the memory; otherwise, the library function 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 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.
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_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_cur_offset;
  The byte offset of the last record known to be on disk.
u_int32_t st_flushcommit;
  The number of log flushes that contained a transaction commit record.
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.]
u_int32_t st_regsize;
  The size of the region.
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 DB_ENV->log_stat function returns a non-zero error value on failure and 0 on success.

# Errors

The DB_ENV->log_stat function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DB_ENV->log_stat function may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.

# See Also

DB_ENV->set_lg_bsize, DB_ENV->set_lg_dir, DB_ENV->set_lg_max, DB_ENV->set_lg_regionmax, DB_ENV->log_archive, log_compare, DB_ENV->log_cursor, DB_ENV->log_file, DB_ENV->log_flush, DB_ENV->log_put, DB_ENV->log_register, DB_ENV->log_stat, DB_ENV->log_unregister, DB_LOGC->close and DB_LOGC->get.`

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