locking - sql server 2012 locked and wont function well -

after time weird behavior on sql server 2012 database. queries wont run, queries contain simple selects. queries alter procedures wont run (they execute , stuck in execution until cancel them).

i ran method see tables locked , 1 see is:

sysobjvalues key (ec05837cd075) s shared

this situation gets stabilized restart sql server service.

some tables in database allow selects , not. though due locks query see locks wont show of db tables locked. causing weird behavior?

btw: here query run locks info:

      select           object_name(p.object_id) tablename         , resource_type         , resource_description         , request_mode         , case request_mode                         when 's'        'shared'                         when 'u'        'update'                         when 'x'        'exclusive'                         when 'is'       'intent shared'                         when 'iu'       'intent update'                         when 'ix'       'intent exclusive'                         when 'siu'      'shared intent update'                         when 'six'      'shared intent exclusive'                         when 'uix'      'update intent exclusive'                         when 'bu'       'bulk update'                         when 'ranges_s' 'shared range s'                         when 'ranges_u' 'shared range u'                         when 'rangei_n' 'insert range'                         when 'rangei_s' 'insert range s'                         when 'rangei_u' 'insert range u'                         when 'rangei_x' 'insert range x'                         when 'rangex_s' 'exclusive range s'                         when 'rangex_u' 'exclusive range u'                         when 'rangex_x' 'exclusive range x'                         when 'sch-m'    'schema-modification'                         when 'sch-s'    'schema-stability'              else null             end request_lock_mode        sys.dm_tran_locks   l            join sys.partitions p              on l.resource_associated_entity_id = p.hobt_id  

thanks

this sounds blocking.

when experience this, in status bar of management studio for query window query hanging. in parentheses after username, e.g.:

domain\username (spid) -----------------^^^^ number 

now, take that number, within parentheses, , open window. in second window, run following:

select blocking_session_id, wait_type    sys.dm_exec_requests   session_id = <spid above>; 

if session shows in blocking_session_id, find out , they're doing.

select *    sys.dm_exec_requests   session_id = <blocking_session_id above>;  dbcc inputbuffer(<that blocking_session_id>); 

you can check if database has old transactions haven't bee rolled or committed, may causing issue:

dbcc opentran();