Virtualbox xkbcommon

Após instalar a versão -5.1-5.1.24 do Virtual Box para Linux 64 Bits, recebi o erro

xkbcommon: ERROR: failed to add default include path /usr/share/X11/xkb
Qt WARNING: Qt: Failed to create XKB context!
Qt WARNING: Use QT_XKB_CONFIG_ROOT environmental variable to provide an additional search path, add ':' as separator to provide several search paths and/or make sure that XKB configuration data directory contains recent enough contents, to update please see http://cgit.freedesktop.org/xkeyboard-config/ .
Qt WARNING: QXcbConnection: XCB error: 145 (Unknown), sequence: 171, resource id: 0, major code: 139 (Unknown), minor code: 20

Solução de contorno: export QT_XKB_CONFIG_ROOT=/usr/share/X11/xkb

gathering statistics

— gather stale statistics

EXEC DBMS_STATS.gather_database_stats(options=>’GATHER STALE’, cascade => TRUE);

— change stale percentage: (default 10%)

EXEC DBMS_STATS.set_database_prefs(‘STALE_PERCENT’, ‘5’);

— gather statistics if empty

EXEC DBMS_STATS.gather_database_stats(options=>’GATHER EMPTY’, cascade => TRUE);

— gather full db stats

EXEC DBMS_STATS.gather_database_stats(estimate_percent => dbms_stats.auto_sample_size, cascade => TRUE);

— gather dict stats

EXEC DBMS_STATS.gather_dictionary_stats;

— gather system stats
EXEC DBMS_STATS.gather_system_stats(‘interval’, interval => 180);

— gather system stats @exadata

EXEC DBMS_STATS.gather_system_stats(‘EXADATA’);

— gather fixed obj stats:

EXEC DBMS_STATS.gather_fixed_objects_stats;

— gather table stats

EXEC DBMS_STATS.gather_table_stats(‘MXMCORP’, ‘CT2000_TTAT_LOG’, estimate_percent => dbms_stats.auto_sample_size, cascade => TRUE);

— gather index stats

EXEC DBMS_STATS.gather_index_stats(‘MXMCORP’, ‘CT2000_TTAT_LOG_IDX1’, estimate_percent => dbms_stats.auto_sample_size);

— table stats lock

BEGIN
DBMS_STATS.LOCK_TABLE_STATS(‘OE’,’ORDERS’);
END;
/

BEGIN
DBMS_STATS.LOCK_SCHEMA_STATS(‘HR’);
END;
/

— table stats unlock

BEGIN
DBMS_STATS.UNLOCK_TABLE_STATS(‘OE’,’ORDERS’);
END;
/

reference:

Click to access twp-bp-for-stats-gather-12c-1967354.pdf

https://blogs.oracle.com/optimizer/entry/fixed_objects_statistics_and_why