46

Someone was running a query on our SQL Server database remotely and their system crashed.

They have no backup of that query and want to see what was run on the server.

Is it possible to find this query in a log or in a history somewhere?

1
  • 3
    For future design you might want to consider adding triggers and audit/history tables. Then would would be able to utilize last updated time/user. – Thomas Stringer Jul 23 '11 at 11:53
52

Similar Grant Fritchey had the issue where he had closed SSMS and lost the query he had been working on...blogged about here: Oh **********!

EDIT

To make this a bit more detail of an answer, the referenced linked above Grant provides a query to simply go to the cache on the instance to pull out the query you had just executed (or atleast attempt to):

SELECT  dest.text
FROM    sys.dm_exec_query_stats AS deqs
        CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest
WHERE   deqs.last_execution_time > '5/19/2011 11:00'
        AND dest.text LIKE 'WITH%';

A few more options that were noted in the comments of Grant's blog:

1
21

2005+, default trace to the rescue.

The default trace rolls over at 20mb but SQL retains the history of 5 traces. With access to the server you could retrieve the *.trc files from the MSSQL\Log directory. If you can't access the server, the following will give you the name of the current default trace file:

SELECT * FROM ::fn_trace_getinfo(default) 

If the current file is for example E:\MSSQL.1\MSSQL\LOG\log_200.trc, the previous files should be log_199.trc, log_198.trc etc. Get the contents of the trace with:

SELECT * FROM fn_trace_gettable('E:\MSSQL.1\MSSQL\LOG\log_199.trc', default)
16

You might be able to retrieve info from cached query plans, check BOL for info on sys.dm_exec_query_stats, or run this from management studio connected to the same database:

SELECT  d.plan_handle ,
        d.sql_handle ,
        e.text

FROM    sys.dm_exec_query_stats d
        CROSS APPLY sys.dm_exec_sql_text(d.plan_handle) AS e

Filter the output with

WHERE text like '%something%'

to narrow the results.

10

If database was in full recovery mode then there might be a chance to recover some data and get insights on what was done by reading transaction log.

Unfortunately this is not supported by default but there are ways to do this.

You can try using third party tools such as ApexSQL Log or SQL Log Rescue (free but SQL 2000 only).

Another option is to try using undocumented functions DBCC LOG or fn_dblog. This is more complex but its free.

2

Query history can be viewed using the system views:

  1. sys.dm_exec_query_stats
  2. sys.dm_exec_sql_text
  3. sys.dm_exec_query_plan

For example, using the following query:

select  top(100)
        creation_time,
        last_execution_time,
        execution_count,
        total_worker_time/1000 as CPU,
        convert(money, (total_worker_time))/(execution_count*1000)as [AvgCPUTime],
        qs.total_elapsed_time/1000 as TotDuration,
        convert(money, (qs.total_elapsed_time))/(execution_count*1000)as [AvgDur],
        total_logical_reads as [Reads],
        total_logical_writes as [Writes],
        total_logical_reads+total_logical_writes as [AggIO],
        convert(money, (total_logical_reads+total_logical_writes)/(execution_count + 0.0)) as [AvgIO],
        [sql_handle],
        plan_handle,
        statement_start_offset,
        statement_end_offset,
        plan_generation_num,
        total_physical_reads,
        convert(money, total_physical_reads/(execution_count + 0.0)) as [AvgIOPhysicalReads],
        convert(money, total_logical_reads/(execution_count + 0.0)) as [AvgIOLogicalReads],
        convert(money, total_logical_writes/(execution_count + 0.0)) as [AvgIOLogicalWrites],
        query_hash,
        query_plan_hash,
        total_rows,
        convert(money, total_rows/(execution_count + 0.0)) as [AvgRows],
        total_dop,
        convert(money, total_dop/(execution_count + 0.0)) as [AvgDop],
        total_grant_kb,
        convert(money, total_grant_kb/(execution_count + 0.0)) as [AvgGrantKb],
        total_used_grant_kb,
        convert(money, total_used_grant_kb/(execution_count + 0.0)) as [AvgUsedGrantKb],
        total_ideal_grant_kb,
        convert(money, total_ideal_grant_kb/(execution_count + 0.0)) as [AvgIdealGrantKb],
        total_reserved_threads,
        convert(money, total_reserved_threads/(execution_count + 0.0)) as [AvgReservedThreads],
        total_used_threads,
        convert(money, total_used_threads/(execution_count + 0.0)) as [AvgUsedThreads],
        case 
            when sql_handle IS NULL then ' '
            else(substring(st.text,(qs.statement_start_offset+2)/2,(
                case
                    when qs.statement_end_offset =-1 then len(convert(nvarchar(MAX),st.text))*2      
                    else qs.statement_end_offset    
                end - qs.statement_start_offset)/2  ))
        end as query_text,
        db_name(st.dbid) as database_name,
        object_schema_name(st.objectid, st.dbid)+'.'+object_name(st.objectid, st.dbid) as [object_name],
        sp.[query_plan]
from sys.dm_exec_query_stats as qs with(readuncommitted)
cross apply sys.dm_exec_sql_text(qs.[sql_handle]) as st
cross apply sys.dm_exec_query_plan(qs.[plan_handle]) as sp
WHERE st.[text] LIKE '%query%'

Current running queries can be seen using the following script:

select ES.[session_id]
      ,ER.[blocking_session_id]
      ,ER.[request_id]
      ,ER.[start_time]
      ,DateDiff(second, ER.[start_time], GetDate()) as [date_diffSec]
      , COALESCE(
                    CAST(NULLIF(ER.[total_elapsed_time] / 1000, 0) as BIGINT)
                   ,CASE WHEN (ES.[status] <> 'running' and isnull(ER.[status], '')  <> 'running') 
                            THEN  DATEDIFF(ss,0,getdate() - nullif(ES.[last_request_end_time], '1900-01-01T00:00:00.000'))
                    END
                ) as [total_time, sec]
      , CAST(NULLIF((CAST(ER.[total_elapsed_time] as BIGINT) - CAST(ER.[wait_time] AS BIGINT)) / 1000, 0 ) as bigint) as [work_time, sec]
      , CASE WHEN (ER.[status] <> 'running' AND ISNULL(ER.[status],'') <> 'running') 
                THEN  DATEDIFF(ss,0,getdate() - nullif(ES.[last_request_end_time], '1900-01-01T00:00:00.000'))
        END as [sleep_time, sec] --Время сна в сек
      , NULLIF( CAST((ER.[logical_reads] + ER.[writes]) * 8 / 1024 as numeric(38,2)), 0) as [IO, MB]
      , CASE  ER.transaction_isolation_level
        WHEN 0 THEN 'Unspecified'
        WHEN 1 THEN 'ReadUncommited'
        WHEN 2 THEN 'ReadCommited'
        WHEN 3 THEN 'Repetable'
        WHEN 4 THEN 'Serializable'
        WHEN 5 THEN 'Snapshot'
        END as [transaction_isolation_level_desc]
      ,ER.[status]
      ,ES.[status] as [status_session]
      ,ER.[command]
      ,ER.[percent_complete]
      ,DB_Name(coalesce(ER.[database_id], ES.[database_id])) as [DBName]
      , SUBSTRING(
                    (select top(1) [text] from sys.dm_exec_sql_text(ER.[sql_handle]))
                  , ER.[statement_start_offset]/2+1
                  , (
                        CASE WHEN ((ER.[statement_start_offset]<0) OR (ER.[statement_end_offset]<0))
                                THEN DATALENGTH ((select top(1) [text] from sys.dm_exec_sql_text(ER.[sql_handle])))
                             ELSE ER.[statement_end_offset]
                        END
                        - ER.[statement_start_offset]
                    )/2 +1
                 ) as [CURRENT_REQUEST]
      ,(select top(1) [text] from sys.dm_exec_sql_text(ER.[sql_handle])) as [TSQL]
      ,(select top(1) [objectid] from sys.dm_exec_sql_text(ER.[sql_handle])) as [objectid]
      ,(select top(1) [query_plan] from sys.dm_exec_query_plan(ER.[plan_handle])) as [QueryPlan]
      ,NULL as [event_info]--(select top(1) [event_info] from sys.dm_exec_input_buffer(ES.[session_id], ER.[request_id])) as [event_info]
      ,ER.[wait_type]
      ,ES.[login_time]
      ,ES.[host_name]
      ,ES.[program_name]
      ,cast(ER.[wait_time]/1000 as decimal(18,3)) as [wait_timeSec]
      ,ER.[wait_time]
      ,ER.[last_wait_type]
      ,ER.[wait_resource]
      ,ER.[open_transaction_count]
      ,ER.[open_resultset_count]
      ,ER.[transaction_id]
      ,ER.[context_info]
      ,ER.[estimated_completion_time]
      ,ER.[cpu_time]
      ,ER.[total_elapsed_time]
      ,ER.[scheduler_id]
      ,ER.[task_address]
      ,ER.[reads]
      ,ER.[writes]
      ,ER.[logical_reads]
      ,ER.[text_size]
      ,ER.[language]
      ,ER.[date_format]
      ,ER.[date_first]
      ,ER.[quoted_identifier]
      ,ER.[arithabort]
      ,ER.[ansi_null_dflt_on]
      ,ER.[ansi_defaults]
      ,ER.[ansi_warnings]
      ,ER.[ansi_padding]
      ,ER.[ansi_nulls]
      ,ER.[concat_null_yields_null]
      ,ER.[transaction_isolation_level]
      ,ER.[lock_timeout]
      ,ER.[deadlock_priority]
      ,ER.[row_count]
      ,ER.[prev_error]
      ,ER.[nest_level]
      ,ER.[granted_query_memory]
      ,ER.[executing_managed_code]
      ,ER.[group_id]
      ,ER.[query_hash]
      ,ER.[query_plan_hash]
      ,EC.[most_recent_session_id]
      ,EC.[connect_time]
      ,EC.[net_transport]
      ,EC.[protocol_type]
      ,EC.[protocol_version]
      ,EC.[endpoint_id]
      ,EC.[encrypt_option]
      ,EC.[auth_scheme]
      ,EC.[node_affinity]
      ,EC.[num_reads]
      ,EC.[num_writes]
      ,EC.[last_read]
      ,EC.[last_write]
      ,EC.[net_packet_size]
      ,EC.[client_net_address]
      ,EC.[client_tcp_port]
      ,EC.[local_net_address]
      ,EC.[local_tcp_port]
      ,EC.[parent_connection_id]
      ,EC.[most_recent_sql_handle]
      ,ES.[host_process_id]
      ,ES.[client_version]
      ,ES.[client_interface_name]
      ,ES.[security_id]
      ,ES.[login_name]
      ,ES.[nt_domain]
      ,ES.[nt_user_name]
      ,ES.[memory_usage]
      ,ES.[total_scheduled_time]
      ,ES.[last_request_start_time]
      ,ES.[last_request_end_time]
      ,ES.[is_user_process]
      ,ES.[original_security_id]
      ,ES.[original_login_name]
      ,ES.[last_successful_logon]
      ,ES.[last_unsuccessful_logon]
      ,ES.[unsuccessful_logons]
      ,ES.[authenticating_database_id]
      ,ER.[sql_handle]
      ,ER.[statement_start_offset]
      ,ER.[statement_end_offset]
      ,ER.[plan_handle]
      ,NULL as [dop]--ER.[dop]
      ,coalesce(ER.[database_id], ES.[database_id]) as [database_id]
      ,ER.[user_id]
      ,ER.[connection_id]
from sys.dm_exec_requests ER with(readuncommitted)
right join sys.dm_exec_sessions ES with(readuncommitted)
on ES.session_id = ER.session_id 
left join sys.dm_exec_connections EC  with(readuncommitted)
on EC.session_id = ES.session_id
where ER.[status] in ('suspended', 'running', 'runnable')
or exists (select top(1) 1 from sys.dm_exec_requests as ER0 where ER0.[blocking_session_id]=ES.[session_id])

This request displays all active requests and all those requests that explicitly block active requests.

All these and other useful scripts are implemented as representations in the SRV database, which is distributed freely. For example, the first script came from the view [inf].[vBigQuery], and the second came from view [inf].[vRequests].

There are also various third-party solutions for query history. I use Query Manager from Dbeaver: enter image description here and Query Execution History from SQL Tools, which is embedded in SSMS: enter image description here

0

If your database is set to full recovery model you can investigate your transaction log backups. See fn_dump_dblog for more informations.

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