DBA SGA Active Session History

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Description
Categories: Diagnostic Pack, Enginatics
Repository: Github
Active session history from the SGA.

Parameter 'Blocked Sessions only' allows a blocking scenario root cause analysis, e.g. by doing a pivot in Excel (see example in the online library).
The link to blocking sessions is deliberately nonunique without jointing to sample_id to increase the chance to fetch the blocking session's additional information such as module, action and client_id.
In some cases, such as row lock scenarios, the blocking session is idle and does not show up in the ASH then.
For scenarios where the blocking sessions are active and part of the ASH, Tanel Poder has a treewalk ash_wait_chains.sql, showing the whole chain of ASH records linked by a unique join, including the sample_id:
https://blog.tanelpoder.com/2013/11/06/diagnosing-buffer-busy-waits-with-the-ash_wait_chains-sql-script-v0-2/ ...  Active session history from the SGA.

Parameter 'Blocked Sessions only' allows a blocking scenario root cause analysis, e.g. by doing a pivot in Excel (see example in the online library).
The link to blocking sessions is deliberately nonunique without jointing to sample_id to increase the chance to fetch the blocking session's additional information such as module, action and client_id.
In some cases, such as row lock scenarios, the blocking session is idle and does not show up in the ASH then.
For scenarios where the blocking sessions are active and part of the ASH, Tanel Poder has a treewalk ash_wait_chains.sql, showing the whole chain of ASH records linked by a unique join, including the sample_id:
https://blog.tanelpoder.com/2013/11/06/diagnosing-buffer-busy-waits-with-the-ash_wait_chains-sql-script-v0-2/

We recommend doing ASH performance analysis with a pivot in Excel rather than by SQL, as Excel's drag- and drop is a lot faster than typing commands manually.
A typical use case is to analyze which EBS application user waited for how many seconds in which forms UI and to drill down further into the SQL or wait event root causes.

Column 'Module Name' shows either the translated EBS module display name or, e.g. for background sessions, the process name (from the program column) to enable pivoting by this column only.
Oracle's background process names are listed here:
https://docs.oracle.com/database/121/REFRN/GUID-86184690-5531-405F-AA05-BB935F57B76D.htm#REFRN104

To identify an object or segment of a hot block, for example causing wait events, Oracle's dba_extents view is unusable due to performance bugs in 19c+, and Franck Pachot published a workaround here:
https://www.dbi-services.com/blog/efficiently-query-dba_extents-for-file_id-block_id/   more

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select
xxen_util.client_time(gash.sample_time_) sample_time,
gash.inst_id,
gash.session_id||' - '||gash.session_serial# sid_serial#,
xxen_util.user_name(gash.module,gash.action,gash.client_id) user_name,
xxen_util.responsibility(gash.module,gash.action) responsibility,
xxen_util.module_type(gash.module,gash.action) module_type,
xxen_util.module_name(gash.module,gash.program) module_name,
case when lower(gash.module) like '%frm%' then 'Forms' when lower(gash.module) like '%fwk%' then 'OAF' end ui_type,
(select so.name from sys.obj$ so where gsa.program_id=so.obj#) code,
case when gsa.program_line#>0 then gsa.program_line# end code_line#,
gash.sql_id,
gash.sql_plan_hash_value plan_hash_value,
&sql_text
xxen_util.time(count(*) over (partition by gash.inst_id, gash.session_id, gash.session_serial#, gash.sql_id)) time_per_sql,
round(100*(count(*) over (partition by gash.inst_id, gash.session_id, gash.session_serial#, gash.sql_id)/count(*) over (partition by gash.inst_id, gash.session_id, gash.session_serial#)),2) percentage,
gash.sql_exec_id-16777216 execution_count,
xxen_util.client_time(gash.sql_exec_start) sql_exec_start,
dp0.object_name||case when dp0.procedure_name is not null then '.'||dp0.procedure_name end entry_procedure,
dp.object_name||case when dp.procedure_name is not null then '.'||dp.procedure_name end procedure,
xxen_util.time((max(gash.sample_time_) over (partition by gash.inst_id, gash.session_id, gash.session_serial#)-min(gash.sample_time_) over (partition by gash.inst_id, gash.session_id, gash.session_serial#))*86400) sess_duration,
xxen_util.time(count(*) over (partition by gash.inst_id, gash.session_id, gash.session_serial#)) sess_active,
xxen_util.client_time(min(gash.sample_time_) over (partition by gash.inst_id, gash.session_id, gash.session_serial#)) sess_first_time,
xxen_util.client_time(min(gash.sample_time_) over (partition by gash.inst_id, gash.session_id, gash.session_serial#, gash.sql_id)) sql_first_time,
gash.session_type,
gash.session_state,
nvl(gash.event,gash.session_state)||
case
when gash.event like 'enq%' and gash.session_state='WAITING' then ' (mode='||bitand(gash.p1,power(2,14)-1)||')'
when gash.event in ('buffer busy waits','gc buffer busy','gc buffer busy acquire','gc buffer busy release') then ' ('||
coalesce(
(select vw.class from (select vw.class, rownum row_num from v$waitstat vw) vw where gash.p3=vw.row_num),
(select decode(mod(bitand(gash.p3,to_number('FFFF','XXXX'))-17,2),0,'undo header',1,'undo data','error') from dual)
)||')'
end event,
gash.wait_class,
rtrim(
case when bitand(gash.time_model,power(2,01))=power(2,01) then 'DBTIME ' end||
case when bitand(gash.time_model,power(2,02))=power(2,02) then 'BACKGROUND ' end||
case when bitand(gash.time_model,power(2,03))=power(2,03) then 'CONNECTION_MGMT ' end||
case when bitand(gash.time_model,power(2,04))=power(2,04) then 'PARSE ' end||
case when bitand(gash.time_model,power(2,05))=power(2,05) then 'FAILED_PARSE ' end||
case when bitand(gash.time_model,power(2,06))=power(2,06) then 'NOMEM_PARSE ' end||
case when bitand(gash.time_model,power(2,07))=power(2,07) then 'HARD_PARSE ' end||
case when bitand(gash.time_model,power(2,08))=power(2,08) then 'NO_SHARERS_PARSE ' end||
case when bitand(gash.time_model,power(2,09))=power(2,09) then 'BIND_MISMATCH_PARSE ' end||
case when bitand(gash.time_model,power(2,10))=power(2,10) then 'SQL_EXECUTION ' end||
case when bitand(gash.time_model,power(2,11))=power(2,11) then 'PLSQL_EXECUTION ' end||
case when bitand(gash.time_model,power(2,12))=power(2,12) then 'PLSQL_RPC ' end||
case when bitand(gash.time_model,power(2,13))=power(2,13) then 'PLSQL_COMPILATION ' end||
case when bitand(gash.time_model,power(2,14))=power(2,14) then 'JAVA_EXECUTION ' end||
case when bitand(gash.time_model,power(2,15))=power(2,15) then 'BIND ' end||
case when bitand(gash.time_model,power(2,16))=power(2,16) then 'CURSOR_CLOSE ' end||
case when bitand(gash.time_model,power(2,17))=power(2,17) then 'SEQUENCE_LOAD ' end||
case when bitand(gash.time_model,power(2,18))=power(2,18) then 'INMEMORY_QUERY ' end||
case when bitand(gash.time_model,power(2,19))=power(2,19) then 'INMEMORY_POPULATE ' end||
case when bitand(gash.time_model,power(2,20))=power(2,20) then 'INMEMORY_PREPOPULATE ' end||
case when bitand(gash.time_model,power(2,21))=power(2,21) then 'INMEMORY_REPOPULATE ' end||
case when bitand(gash.time_model,power(2,22))=power(2,22) then 'INMEMORY_TREPOPULATE ' end||
case when bitand(gash.time_model,power(2,23))=power(2,23) then 'TABLESPACE_ENCRYPTION ' end
) time_model,
xxen_util.meaning(decode(gash.in_parse,'Y','Y'),'YES_NO',0) in_parse,
xxen_util.meaning(decode(gash.in_hard_parse,'Y','Y'),'YES_NO',0) in_hard_parse,
gash.qc_instance_id,
gash.qc_session_id||nvl2(gash.qc_session_serial#,' - '||gash.qc_session_serial#,null) qc_sid_serial#,
gash.sql_plan_operation,
gash.sql_plan_options,
(select do.owner||'.'||do.object_name||' ('||do.object_type||')' from dba_objects do where gash.current_obj#=do.object_id) object,
decode(gash.p1text,'file#',gash.p1) file_id,
decode(gash.p2text,'block#',gash.p2) block_id,
decode(gash.blocking_session_status,'VALID','blocked') blocked_status,
gash.blocking_inst_id,
nvl2(gash.blocking_session,gash.blocking_session||' - '||gash.blocking_session_serial#,null) blocking_sid_serial#,
&blocking_columns
gash.pga_allocated/1000000 pga_allocated,
sum(gash.pga_allocated) over (partition by gash.sample_time)/1000000 pga_total,
gash.pga_allocated/xxen_util.zero_to_null(sum(gash.pga_allocated) over (partition by gash.sample_time))*100 pga_percentage,
gash.temp_space_allocated/1000000 temp_space_allocated,
sum(gash.temp_space_allocated) over (partition by gash.sample_time)/1000000 temp_space_total,
gash.temp_space_allocated/xxen_util.zero_to_null(sum(gash.temp_space_allocated) over (partition by gash.sample_time))*100 temp_space_percentage,
count(*) over (partition by gash.sample_time) active_sessions,
gash.machine,
lower(gash.sql_opname) command_type,
du.username schema,
gash.action,
gash.module,
gash.program,
gash.p1text,
gash.p1,
gash.p2text,
gash.p2,
gash.p3text,
gash.p3
from
&request_id_table
(select cast(gash.sample_time as date) sample_time_, max(gash.temp_space_allocated/1000000) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) max_temp_space_allocated, gash.* from gv$active_session_history gash) gash,
(
select distinct
gash.inst_id,
gash.session_id,
gash.session_serial#,
max(gash.client_id) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) client_id,
max(gash.action) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) action,
max(gash.module) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) module,
max(gash.program) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) program,
max(gash.session_type) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) session_type,
max(gash.machine) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) machine,
max(decode(gash.p1text,'file#',gash.p1)) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) file_id,
max(decode(gash.p2text,'block#',gash.p2)) keep (dense_rank last order by gash.sample_id) over (partition by gash.inst_id,gash.session_id,gash.session_serial#) block_id
from
gv$active_session_history gash
where
'&show_blocking_session'='Y'
) gash0,
dba_procedures dp0,
dba_procedures dp,
(
select distinct
gsa.sql_id,
min(gsa.inst_id) keep (dense_rank first order by gsa.inst_id, gsa.plan_hash_value) over (partition by gsa.sql_id) inst_id,
min(gsa.plan_hash_value) keep (dense_rank first order by gsa.inst_id, gsa.plan_hash_value) over (partition by gsa.sql_id) plan_hash_value
from
gv$sqlarea gsa
where
2=2
) gsa0,
gv$sqlarea gsa,
dba_users du
where
1=1 and
gash.plsql_entry_object_id=dp0.object_id(+) and
gash.plsql_entry_subprogram_id=dp0.subprogram_id(+) and
gash.plsql_object_id=dp.object_id(+) and
gash.plsql_subprogram_id=dp.subprogram_id(+) and
gash.sql_id=gsa0.sql_id(+) and
gsa0.sql_id=gsa.sql_id(+) and
gsa0.inst_id=gsa.inst_id(+) and
gsa0.plan_hash_value=gsa.plan_hash_value(+) and
gash.user_id=du.user_id(+) and
gash.blocking_inst_id=gash0.inst_id(+) and
gash.blocking_session=gash0.session_id(+) and
gash.blocking_session_serial#=gash0.session_serial#(+)
order by
sample_time,
sess_first_time desc,
percentage desc,
sql_first_time desc
Parameter Name SQL text Validation
User Name 
gash.client_id like upper(:user_name)
 LOV
Module Type 
xxen_util.module_type(gash.module,gash.action)=:module_type
 LOV
Module contains 
lower(gash.module) like '%'||lower(:module)||'%'
 LOV
Show Blocking Session Info 
Y
 LOV
Blocked Sessions only 
gash.blocking_session is not null
 LOV
Request Id 
gash.sample_time between fcr.actual_start_date and nvl(fcr.actual_completion_date,sysdate)
 LOV
Restrict User Name to Client_ID 
fcr.user_name=gash.client_id
 LOV
From Time 
gash.sample_time>=:from_time
 DateTime
To Time 
gash.sample_time<=:to_time
 DateTime
Package Name starts with 
gsa.program_id in (select do.object_id from dba_objects do where do.object_name like upper(:package_name)||'%')
 LOV
Wait Event 
gash.event=:event_name
 LOV
Exclude Wait Event 
nvl(gash.event,'x')<>:event_name
 LOV
SID - Serial# 
gash.session_id=substr(:sid_serial,1,instr(:sid_serial,' - ')-1) and
gash.session_serial#=substr(:sid_serial,instr(:sid_serial,' - ')+3)
 LOV
SQL Id 
gash.sql_id=:sql_id
 Char
Max Temp Space larger than GB 
gash.max_temp_space_allocated>=1000*:max_temp_space_allocated_gb
 Char
Show SQL Text 
gsa.sql_fulltext sql_text,
 LOV
UI Sessions only 
(gash.module like '%:frm:%' or gash.module like 'frmweb@%' or gash.module like '%:fwk:%')
 LOV
Session Type 
gash.session_type=decode(:session_type,'Foreground','FOREGROUND','Background','BACKGROUND',gash.session_type)
 LOV
Instance Id 
gash.inst_id=:inst_id
 LOV
Machine 
gash.machine=:machine
 LOV
Schema 
du.username=:schema
 LOV
Action contains 
lower(gash.action) like '%'||lower(:action)||'%'
 Char
Program contains 
gsa.program_id in (select do.object_id from dba_objects do where lower(do.object_name) like '%'||lower(:program)||'%')
 Char
Entry Procedure contains 
lower(dp0.object_name||case when dp0.procedure_name is not null then '.'||dp0.procedure_name end) like '%'||lower(:entry_procedure)||'%'
 Char
Diagnostic Pack enabled 
0=0
 LOV
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