Basic Replication -- 12 : MV Refresh Captured in AWR

Building on the example of an Index having been created on a Materialized View  in my previous blog post in this series, I've captured some information from the AWR report in 19c when this code is executed :

SQL> delete source_table_1;

72454 rows deleted.

SQL> insert into source_table_1 select object_id, owner, object_name from source_table_2;

72366 rows created.

SQL> commit;

Commit complete.

SQL> exec dbms_mview.refresh('MV_OF_SOURCE');

PL/SQL procedure successfully completed.

SQL>
SQL> exec dbms_mview.refresh('MV_1');

PL/SQL procedure successfully completed.

(Note that "MV_OF_SOURCE" is not dependent on SOURCE_TABLE_1 and as really had no rows to refresh, did not cause any load).

Some information in the AWR Report (note that this is 19.3) :

SQL ordered by Elapsed Time             DB/Inst: ORCLCDB/ORCLCDB  Snaps: 54-55
-> Resources reported for PL/SQL code includes the resources used by all SQL
   statements called by the code.
-> % Total DB Time is the Elapsed Time of the SQL statement divided
   into the Total Database Time multiplied by 100
-> %Total - Elapsed Time  as a percentage of Total DB time
-> %CPU   - CPU Time      as a percentage of Elapsed Time
-> %IO    - User I/O Time as a percentage of Elapsed Time
-> Captured SQL account for  108.1% of Total DB Time (s):              30
-> Captured PL/SQL account for   85.2% of Total DB Time (s):              30

        Elapsed                  Elapsed Time
        Time (s)    Executions  per Exec (s)  %Total   %CPU    %IO    SQL Id
---------------- -------------- ------------- ------ ------ ------ -------------
            16.1              1         16.09   53.5   12.8   21.6 2uusn1kyhm9h8
Module: SQL*Plus
   PDB: ORCLPDB1
BEGIN dbms_mview.refresh('MV_1'); END;

             8.7              1          8.66   28.8    5.3   13.6 8chh7ksnytb52
   PDB: ORCLPDB1
delete from "HEMANT"."MLOG$_SOURCE_TABLE_1" where snaptime$$ <= :1

             4.5              1          4.55   15.1   17.3   75.6 57ctmbtabx1rw
Module: SQL*Plus
   PDB: ORCLPDB1
BEGIN dbms_mview.refresh('MV_OF_SOURCE'); END;

             4.0              1          3.96   13.2   37.2   26.1 dsyxhpb9annru
Module: SQL*Plus
   PDB: ORCLPDB1
delete source_table_1

             3.7        144,820          0.00   12.3   36.7    8.3 9ucb4uxnvzxc8
Module: SQL*Plus
   PDB: ORCLPDB1
INSERT /*+ NO_DST_UPGRADE_INSERT_CONV IDX(0) */ INTO "HEMANT"."MLOG$_SOURCE_TABL
E_1" (dmltype$$,old_new$$,snaptime$$,change_vector$$,xid$$,"OBJECT_ID") VALUES (
:d,:o,to_date('4000-01-01:00:00:00','YYYY-MM-DD:HH24:MI:SS'),:c,:x,:1)

             3.5              1          3.52   11.7   19.7   45.9 dxnyhyq7sqf8j
   PDB: ORCLPDB1
DELETE FROM "HEMANT"."MV_1" SNAP$ WHERE "OBJ_ID" IN (SELECT * FROM (SELECT MLOG$
."OBJECT_ID""OBJ_ID" FROM "HEMANT"."MLOG$_SOURCE_TABLE_1" MLOG$ WHERE "SNAPTIME
$$"> :1 AND ("DMLTYPE$$" != 'I')) AS OF SNAPSHOT(:B_SCN) )

             3.3              1          3.25   10.8   45.2     .6 9n1gw9vpj9248
Module: SQL*Plus
   PDB: ORCLPDB1
insert into source_table_1 select object_id, owner, object_name from source_tabl
e_2

             2.3              2          1.14    7.6   18.4   77.4 94z4z19ygx34a
Module: SQL*Plus
   PDB: ORCLPDB1
begin sys.dbms_irefstats.run_sa(:1, :2, :3, :4, :5, :6); end;

             2.1              1          2.11    7.0   19.1   21.6 a2sctn32qtwnf
   PDB: ORCLPDB1
/* MV_REFRESH (MRG) */ MERGE INTO "HEMANT"."MV_1""SNA$" USING (SELECT * FROM (S
ELECT CURRENT$."OBJ_ID",CURRENT$."OBJ_OWNER",CURRENT$."OBJ_NAME" FROM (SELECT "S
OURCE_TABLE_1"."OBJECT_ID""OBJ_ID","SOURCE_TABLE_1"."OWNER""OBJ_OWNER","SOURCE
_TABLE_1"."OBJECT_NAME""OBJ_NAME" FROM "SOURCE_TABLE_1""SOURCE_TABLE_1") CURRE

             1.7              1          1.67    5.6   50.3   43.5 btqubgr940awu
Module: sqlplus@oracle-19c-vagrant (TNS V1-V3)
   PDB: CDB$ROOT
BEGIN dbms_workload_repository.create_snapshot(); END;

             1.3              1          1.33    4.4   27.3     .0 ggaxdw7tpmqjb
   PDB: ORCLPDB1
update "HEMANT"."MLOG$_SOURCE_TABLE_1" set snaptime$$ = :1 where snaptime$$ > t
o_date('2100-01-01:00:00:00','YYYY-MM-DD:HH24:MI:SS')

             0.9             89          0.01    3.1    1.7   98.6 3un99a0zwp4vd
   PDB: ORCLPDB1
select owner#,name,namespace,remoteowner,linkname,p_timestamp,p_obj#, nvl(proper
ty,0),subname,type#,flags,d_attrs from dependency$ d, obj$ o where d_obj#=:1 and
 p_obj#=obj#(+) order by order#

             0.5            183          0.00    1.6    6.0   98.3 2sxqgx5hx76qr
   PDB: ORCLPDB1
select /*+ rule */ bucket, endpoint, col#, epvalue, epvalue_raw, ep_repeat_count
, endpoint_enc from histgrm$ where obj#=:1 and intcol#=:2 and row#=:3 order by b
ucket

             0.5              2          0.23    1.5   15.0   70.0 6tbg6ydrx9jmm
Module: SQL*Plus
   PDB: ORCLPDB1
begin dbms_irefstats.purge_stats_mv_rp(in_time => :1, in_objnum => :2, in_r
etention_period => :3); end;

             0.4              9          0.04    1.3   15.4   69.2 g1s379sraujaq
Module: SQL*Plus
   PDB: ORCLPDB1
DELETE FROM SYS.MVREF$_STMT_STATS WHERE REFRESH_ID = :B2 AND MV_OBJ# = :B1

             0.4              2          0.20    1.3   16.4   76.8 8szmwam7fysa3
Module: SQL*Plus
   PDB: ORCLPDB1
insert into wri$_adv_objspace_trend_data select timepoint, space_usage, space_a
lloc, quality from table(dbms_space.object_growth_trend(:1, :2, :3, :4, NULL, N
ULL, NULL, 'FALSE', :5, 'FALSE'))

             0.4             59          0.01    1.3    9.5   97.3 03guhbfpak0w7
   PDB: CDB$ROOT
select /*+ index(idl_ub1$ i_idl_ub11) */ piece#,length,piece from idl_ub1$ where
 obj#=:1 and part=:2 and version=:3 order by piece#

             0.3              2          0.15    1.0   11.0     .0 a8xypykqc348c
   PDB: ORCLPDB1
BEGIN dbms_stats_internal.advisor_setup_obj_filter(:tid, :rid, 'EXECUTE', FAL
SE); END;

             0.3              2          0.15    1.0    8.7     .0 avf5k3k0x0cxn
   PDB: ORCLPDB1
 insert into stats_advisor_filter_obj$ (rule_id, obj#, flag
s, type) select :rule_id, obj#, :flag_include, :type_expanded
 from stats_advisor_filter_obj$ where type = :type_priv
 and (bitand(flags, :flag_orcl_owned) = 0 or :get_orcl_objects = 'T')

Quite interesting that there are large number of operations that occur.

Unlike a Trace File, the AWR does not report SQL operations as a chronologically-ordered sequence.  In this case, they are ordered by Elapsed Time per operation.

Also, remember that PL/SQL calls will include the time for "child" SQL calls, so you will encounter double-counting if you add up the figures (e.g. the "dbms_mview.refresh('MV_1');" call included a number of SQL calls --- technically you can identify them only if you *trace* the session making this PL/SQL call.  However, since there was no other activity in this database, almost everything that happened appears in this AWR extract.

The actual calls "delete source_table_1;" and "insert into source_table_1 select object_id, owner, object_name from source_table_2;" were issued *before* the "exec dbms_mview.refresh('MV_1');" and are are not "child" calls.  The child calls that do appear in the AWR are not necessarily in the same chronological order of their execution.

The interesting "child" calls from the "dbms_mview.refresh" call that I would like to point out are :

delete from "HEMANT"."MLOG$_SOURCE_TABLE_1" where snaptime$$ <= :1

INSERT /*+ NO_DST_UPGRADE_INSERT_CONV IDX(0) */ INTO "HEMANT"."MLOG$_SOURCE_TABL
E_1" (dmltype$$,old_new$$,snaptime$$,change_vector$$,xid$$,"OBJECT_ID") VALUES (
:d,:o,to_date('4000-01-01:00:00:00','YYYY-MM-DD:HH24:MI:SS'),:c,:x,:1)

DELETE FROM "HEMANT"."MV_1" SNAP$ WHERE "OBJ_ID" IN (SELECT * FROM (SELECT MLOG$
."OBJECT_ID""OBJ_ID" FROM "HEMANT"."MLOG$_SOURCE_TABLE_1" MLOG$ WHERE "SNAPTIME
$$"> :1 AND ("DMLTYPE$$" != 'I')) AS OF SNAPSHOT(:B_SCN) )

/* MV_REFRESH (MRG) */ MERGE INTO "HEMANT"."MV_1""SNA$" USING (SELECT * FROM (S
ELECT CURRENT$."OBJ_ID",CURRENT$."OBJ_OWNER",CURRENT$."OBJ_NAME" FROM (SELECT "S
OURCE_TABLE_1"."OBJECT_ID""OBJ_ID","SOURCE_TABLE_1"."OWNER""OBJ_OWNER","SOURCE
_TABLE_1"."OBJECT_NAME""OBJ_NAME" FROM "SOURCE_TABLE_1""SOURCE_TABLE_1") CURRE

In my next post, I'll share some other findings after I found something interesting in the AWR report.