Tales From A Lazy Fat DBA

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Some of the new exotic wait events in Oracle 21c …

Posted by FatDBA on November 12, 2022

Hi Guys,


Lately I was doing tests on Oracle 21c and came across few of the exotic new wait events added to Oracle 21c. I was using 21.3.0.0.0 and have noticed few new Exadata, ASM, Dataguard, AI/ML, Exascale, Cluster, exa persistent memory, CTWR etc. specific waits were added to the database. I have also noticed some strange looking waits as well i.e. ‘Spare1′,’Spare2′,’Spare3’ ….

Being an innovation release, and since this is a beta version, there is no document available or published for the customer for any of these new waits on Metalink

Couple of new ‘Bloom Filter‘ related waits added to 21c
Bloom Filter EOF
Bloom Filter Fetch

Bunch of new Exadata ‘smart Index|Table scan’ related, User I/O classed wait events added to 21c are
cell smart index scan request
cell smart index scan: db timezone upgrade
cell smart index scan: disabled by user
cell smart index scan: pass through
cell smart table scan request
cell smart table scan: db timezone upgrade
cell smart table scan: disabled by user
cell smart table scan: pass through
cell worker online completion
cell worker retry

Few of the new machine learning & Artificial Intellegence related wait events added in 21c are
enq: AI - Seek operation
enq: AI - dequeue operation
enq: AI - lwm update operation
enq: AI - remove subscriber
enq: AI - start cross operation
enq: AI - stop cross operation
enq: AI - truncate operation

Some of the new RAC (cluster class), global cache (cache fusion) block related waits added to 21c are
gc cr block direct read
gc current block direct read

Some of the new EDSLib/EBSLib latch waits, which are used to gum the code between RDBMS and Exascale storage added in 21c are given below.
latch: EDSLib File
latch: EDSLib Message
latch: EDSLib Root
latch: EGSLib Root
latch: EGSLibDS Root
latch: EGSLibDataStore Object
latch: EGSLibDataStoreShard Object
latch: EGSLibForum Object
latch: EGSLibNet Root
latch: EGSLibSP Root
latch: EGSLibStoragePool Object
latch: EGSLibStoragePoolRing Object
latch: FOB s.o list parent latch

This is by far the most interesting one, with no name and they seem some sort of free or extra wait events names. I am familiar with few of the other ‘spare’ i.e. “enq: BS – krb spare”, “enq: SP..xx”, “enq: SX.xx.xxx“, but these are different
spare 10
spare 2
spare 3
spare 4
spare 5
spare 6
spare 7
spare 8
spare 9

Couple of new ASM related wait events were added too
enq: AM - ASM Scrubbing
enq: AM - ASM used quota calculation

Some of the new enqueue waits on Change Tracking file are
enq: CT - CTWR DBA buffer resize
enq: CT - CTWR datafile sync
enq: CT - CTWR thread checkpoint

Some of the new enqueue related waits on Exadata Persistent Memory (PMEM)
enq: FF - PMEMfs - ODM
enq: FF - PMEMfs - Param
enq: FF - PMEMfs - Resize
enq: FF - PMEMfs - aXtnd pool
enq: FF - PMEMfs - reSze pool

Hope It Helped!
Prashant Dixit

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Kafka Java Client for Transactional Event Queues (TEQ), Another great feature added to Oracle 21c …

Posted by FatDBA on November 6, 2022

Hi Guys,

Recently I was testing some advance queuing functions to setup an asynchronous communication (using event queues) between few applications and users on Oracle 21c database, to build a messaging platform. I was looking for a way to connect my client side libraries to allow Kafka APIs to connect to Oracle DB.

I had no clue how to do this integration, and then I came across this official documentation which talks about a new functionality in Oracle Database Version 21c – Kafka Java Client for Transactional Event Queues (TEQ) that enables Kafka application compatibility with Oracle Database. This provides easy migration of Kafka applications to TEQ.

Oracle Transactional Event Queue (TEQ) makes it easy to implement event-based applications. It is also highly integrated with Apache Kafka. Apart from enabling apps that use Kafka APIs to transparently operate on Oracle TEQ, Oracle TEQ also supports bi-directional information flow between TEQ and Kafka, so that changes are available in TEQ or Kafka as soon as possible in near-real-time.

Apache Kafka Connect is a framework included in Apache Kafka that integrates Kafka with other systems. Oracle TEQ will provide standard JMS package and related JDBC, Transaction packages to establish the connection and complete the transactional data flow. Oracle TEQ configures standard Kafka JMS connectors to establish interoperability and complete the data flow between the two messaging systems.

Another great blog post on the topic : https://docs.oracle.com/en/database/oracle/oracle-database/21/adque/Kafka_cient_interface_TEQ.html#GUID-94589C97-F323-4607-8C3A-10A0EDF9DA0D

Hope It Helps!
Prashant Dixit

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TRANLOGOPTIONS, a crucial performance parameter, Golden Gate 21c, a BUG and a quick workaround …

Posted by FatDBA on October 23, 2022

One of the crucial performance parameter for Golden gate extract process is TRANLOGOPTIONS which controls the way that it interacts with the transaction log. You can use multiple TRANLOGOPTIONS statements in the same parameter file, or you can specify multiple options within the same TRANLOGOPTIONS statement.

There are lot of performance related options i.e. INCLUDEAUX (AUX trails when reading audit trails), DBLOGREADERBUFSIZE etc. that you can use with TRANLOGOPTIONS parameter, but recently I’d tried one of the tuning parameter PERFORMANCEPROFILE with our medium intensity workload. It can be set to HIGH and MEDIUM (default). It helps achieve better performance by grouping the parameters that affect performance. Once the performance profile is set up, this option automatically configures the applicable parameters, to achieve the desired throughput and latency.

We’d used this parameter in one of our 21c (21.7.0) GG installation with TRANLOGOPTIONS PERFORMANCEPROFILE HIGH, but immediately we’d started seeing spikes in extract’s latency. This was might be because it increases the Extract’s read buffer size to 8MB and the rule to purge the extract read buffer is either when the buffer is full or there is no ingress records for 0.2 seconds. Therefore, any uninterrupted workload with Extract consumption rate below 8MB will result in integrated Extract latency to exceed 1 second.

We’d checked with Oracle support and as a quick temporary solution they’d suggested to not use PERFORMANCEPROFILE parameter with HIGH flag, as the Extract consumption/intake rates are below specific value, such as ~15 MB/sec to get ~0.5 second extract response times. Hence we’d set the buffer size to one-third of the redo generation rate in MB/sec to get ~0.3 second maximum Extract latency. They also marked this as Bug 33772499 for GG 21c for July 2022 release.

Hope It Helped!
Prashant Dixit

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SUMMARY, my favorite Trace File Analyzer (TFA) command …

Posted by FatDBA on October 16, 2022

Hi Guys,

Trace File Analyzer (TFA) is one of the popular Oracle provided toolkit that is very useful when you are dealing with any ORA error and want to pack incident files or when you want to monitor your database using oratop (now part of tfa), or want to run orachk (part of tfa) for a health check of your entire Oracle software stack for issue detection. It also comes with support tools like OSWatcher, process watcher and darda which we all are very much familiar. Today’s post is about one of my favorite TFA utilities option/flag ‘Summary’ which is not that commonly used, but is one of the cool things that we you can do with the TFA.

For this post I have used TFA version 21.2.0.0.0, I suggest to use latest version as it comes with bug fixes and lot of new features.

Feature : ‘summary‘
This flag/function of TFA provides you a detailed (high level) real time status summary of your full DB system. It collects stats of your CRS, ASM, ACFS, Database, Patching Info, Network, Listeners and Operating System. Once you execute ‘summary’ mode within TFA command line (TFACTL), it will take you to tfactl_summary mode or SUMMARY Command-Line Interface (CLI) from where you can select from multiple options to view component wise statistics. The best part is you can even save the report in the form of HTML page (using option q) which is more fancy and easy to read version, otherwise text based is the default version.

Alright lets get started, I am going to call the ‘summary’ option and will see what is there for us.

tfactl>
tfactl>
tfactl> summary

  Executing Summary in Parallel on Following Nodes:
    Node : nodeabc
    Node : nodexyz

LOGFILE LOCATION : /u01/app/grid/oracle.ahf/data/repository/suptools/nodeabc/summary/root/20221015052849/log/summary_command_20221015052849_nodeabc_32378.log

  Component Specific Summary collection :
    - Collecting CRS details ... Done.
    - Collecting ASM details ... Done.
    - Collecting ACFS details ... Done.
    - Collecting DATABASE details ... Done.
    - Collecting PATCH details ... Done.
    - Collecting LISTENER details ... Done.
    - Collecting NETWORK details ... Done.
    - Collecting OS details ... Done.
    - Collecting TFA details ... Done.
    - Collecting SUMMARY details ... Done.

  Remote Summary Data Collection : In-Progress - Please wait ...
  - Data Collection From Node - nodexyz .. Done.

  Prepare Clusterwide Summary Overview ... Done
      cluster_status_summary

  COMPONENT   STATUS    DETAILS
+-----------+---------+---------------------------------------------------------------------------------------------------+
  CRS         PROBLEM   .-----------------------------------------------.
                        | CRS_SERVER_STATUS   : ONLINE                  |
                        | CRS_STATE           : ONLINE                  |
                        | CRS_INTEGRITY_CHECK : FAIL                    |
                        | CRS_RESOURCE_STATUS : OFFLINE Resources Found |
                        '-----------------------------------------------'
  ASM         PROBLEM   .-------------------------------------------------------.
                        | ASM_DISK_SIZE_STATUS : WARNING - Available Size < 20% |
                        | ASM_BLOCK_STATUS     : PASS                           |
                        | ASM_CHAIN_STATUS     : PASS                           |
                        | ASM_INCIDENTS        : PASS                           |
                        | ASM_PROBLEMS         : PASS                           |
                        '-------------------------------------------------------'
  ACFS        OFFLINE   .-----------------------.
                        | ACFS_STATUS : OFFLINE |
                        '-----------------------'
  DATABASE    PROBLEM   .-----------------------------------------------------------------------------------------------.
                        | ORACLE_HOME_DETAILS                                                        | ORACLE_HOME_NAME |
                        +----------------------------------------------------------------------------+------------------+
                        | .------------------------------------------------------------------------. | OraDB19000_home1 |
                        | | PROBLEMS | INCIDENTS | DB_BLOCKS | DATABASE_NAME | STATUS  | DB_CHAINS | |                  |
                        | +----------+-----------+-----------+---------------+---------+-----------+ |                  |
                        | | PROBLEM  | PROBLEM   | PASS      | FATDBA1       | PROBLEM | PROBLEM   | |                  |
                        | '----------+-----------+-----------+---------------+---------+-----------' |                  |
                        '----------------------------------------------------------------------------+------------------'
  PATCH       OK        .----------------------------------------------.
                        | CRS_PATCH_CONSISTENCY_ACROSS_NODES      : OK |
                        | DATABASE_PATCH_CONSISTENCY_ACROSS_NODES : OK |
                        '----------------------------------------------'
  LISTENER    OK        .-----------------------.
                        | LISTNER_STATUS   : OK |
                        '-----------------------'
  NETWORK     OK        .---------------------------.
                        | CLUSTER_NETWORK_STATUS :  |
                        '---------------------------'
  OS          OK        .-----------------------.
                        | MEM_USAGE_STATUS : OK |
                        '-----------------------'
  TFA         OK        .----------------------.
                        | TFA_STATUS : RUNNING |
                        '----------------------'
  SUMMARY     OK        .------------------------------------.
                        | SUMMARY_EXECUTION_TIME : 0H:1M:41S |
                        '------------------------------------'
+-----------+---------+---------------------------------------------------------------------------------------------------+


        ### Entering in to SUMMARY Command-Line Interface ###

tfactl_summary>list

  Components : Select Component - select [component_number|component_name]
        1 => overview
        2 => crs_overview
        3 => asm_overview
        4 => acfs_overview
        5 => database_overview
        6 => patch_overview
        7 => listener_overview
        8 => network_overview
        9 => os_overview
        10 => tfa_overview
        11 => summary_overview

tfactl_summary>
tfactl_summary>
tfactl_summary>

Now when all statistics summaries are collected, this will automatically take us to the SUMMARY Command-Line Interface (tfactl_summary>) where if we use ‘list’ option will bring the entire chart of options to choose from (see above all 11 different areas). Next I am going to select option 3 to get ASM_OVERVIEW from tfactl_summary CLI which when selected will further take you to another linked CLI that is tfactl_summary_asmoverview> which will further gives you details of your entire cluster, like in my case I have node machines as a part of this cluster.

So basically the flow will be something like this
tfactl —> Use summary command and enter into tfactl_summary —> Choose option from the list using ‘list’ command and enter into option related CLI (i.e. tfactl_summary_asmoverview>) and choose option or node to view stats.

Please take a look below for better understanding.

tfactl_summary>3

  ASM_INSTANCE   HOSTNAME   ASM_DISK_SIZE_STATUS             ASM_BLOCK_STATUS   ASM_CHAIN_STATUS   ASM_INCIDENTS   ASM_PROBLEMS
+--------------+----------+--------------------------------+------------------+------------------+---------------+--------------+
  +ASM1          nodeabc    WARNING - Available Size < 20%   PASS               PASS               PASS            PASS
+--------------+----------+--------------------------------+------------------+------------------+---------------+--------------+

tfactl_summary_asmoverview>list

  Status Type: Select Status Type - select [status_type_number|status_type_name]
        1 => asm_clusterwide_status
        2 => asm_nodeabc
        3 => asm_nodexyz

tfactl_summary_asmoverview>2


     =====> asm_problems

  ADR_EVENTS
+---------------------------------------------------------------------------------------+
  .-----------------------------------------------------------------------------------.
  | STATUS_TYPE          | DETAILS                                                    |
  +----------------------+------------------------------------------------------------+
  | ADR_HOME             | /u01/app/grid/diag/clients/user_oracle/host_2241630980_110 |
  | ORACLE_HOME          | /u01/app/19.0.0.0/grid                                     |
  | PROBLEM_STATUS_CHECK | host_2241630980_110:PASS                                   |
  '----------------------+------------------------------------------------------------'
..
....
......

     =====> asm_instancefiles

  file_number   compound_index   bytes         block_size   name               modification_date   creation_date   striped   incarnation   group_number
+-------------+----------------+-------------+------------+------------------+-------------------+---------------+---------+-------------+--------------+
          253         16777469          1536          512   ASMPARAMETERFILE   31-AUG-20           31-AUG-20       COARSE     1049911287              1
          255         16777471     165974016         4096   OCRFILE            18-APR-21           31-AUG-20       COARSE     1049911291              1
          256         16777472         21504          512   PASSWORD           31-AUG-20           31-AUG-20       COARSE     1049911289              1
          257         16777473         11264          512   PASSWORD           31-AUG-20           31-AUG-20       COARSE     1049911469              1
          258         16777474      20971520        32768   ASMVDRL            18-APR-21           31-AUG-20       CUSTOM     1049912853              1
          259         16777475    5368709120      1048576   ASMVOL             18-APR-21           31-AUG-20       CUSTOM     1049912853              1
          260         16777476    5368717312         8192   DATAFILE           14-OCT-22           31-AUG-20       COARSE     1049923157          
...
....
     =====> asm_status_summary

  STATUS_TYPE                    STATUS
+------------------------------+-----------------------------------------------------------------+
  SYSTEM_DATE                    Sat Oct 15 05:29:06 UTC 2022
  ASM_HOME                       /u01/app/19.0.0.0/grid
  ASM_VERSION
  ASM_INSTANCE                   +ASM1
  ASM_DIAGNOSTICS_TRACE_FOLDER   /u01/app/grid/diag/asm/+asm/+ASM1/trace
  ASM_CHAIN_STATUS               PASS
  ASM_BLOCK_STATUS               PASS
  ASM_DISK_SIZE_STATUS           WARNING - Available Size < 20%
  ASM_DISK_GROUP_SUMMARY         .------------------------.
                                 | name | disk_size_alert |
                                 +------+-----------------+
                                 | DATA | Red : 14%       |
                                 | RECO | Red : 8%        |
                                 '------+-----------------'
  ADR_EVENTS                     .-------------------------------------------------------------.
                                 | HOSTNAME | INCIDENT_STATUS | INSTANCE_NAME | PROBLEM_STATUS |
                                 +----------+-----------------+---------------+----------------+
                                 | nodeabc  | PASS            | ASM1          | PASS           |
                                 '----------+-----------------+---------------+----------------'
+------------------------------+-----------------------------------------------------------------+

    =====> asm_diskgroup_details

  allocation_unit_size   name   disk_size_alert   state     usable_file_mb   type   total_mb   group_number
+----------------------+------+-----------------+---------+----------------+------+----------+--------------+
               4194304   DATA   Red : 14%         MOUNTED          5141366   HIGH   35163648              1
               4194304   RECO   Red : 8%          MOUNTED           731597   HIGH    8788992              2
+----------------------+------+-----------------+---------+----------------+------+----------+--------------+


  Status Type: Select Status Type - select [status_type_number|status_type_name]
        1 => asm_clusterwide_status
        2 => asm_nodeabc
        3 => asm_nodexyz








--
--
--
--
--
--
--
-- Next I am going to select option 9 to view OS_OVERVIEW
--
--
tfactl_summary>9

  IDLE_TIME   #CORES   HOSTNAME   SWAP_USED   MEM_USED   TASKS   LOAD   #PROCESSORS
+-----------+--------+----------+-----------+----------+-------+------+-------------+
       94.4       12   nodeabc     0.00 %      59.94 %    1971   2.44            48
+-----------+--------+----------+-----------+----------+-------+------+-------------+

tfactl_summary_osoverview>list

  Status Type: Select Status Type - select [status_type_number|status_type_name]
        1 => os_clusterwide_status
        2 => os_nodeabc
        3 => os_nodexyz

tfactl_summary_osoverview>2


     =====> os_disk_details

  PATH
+------------------------------------+
  /dev/asm/commonstore-332
  /dev/mapper/IO1_P1S00_2758906044
  /dev/mapper/IO1_P1S01_2758880300
  /dev/mapper/IO1_P1S02_2758924712
  /dev/mapper/IO1_P1S03_2758924872
  /dev/mapper/IO1_P1S04_2758924616
  /dev/mapper/IO1_P1S05_2758906308
  /dev/mapper/VolGroupSys-LogVolOpt
  /dev/mapper/VolGroupSys-LogVolRoot
  /dev/mapper/VolGroupSys-LogVolSwap
  /dev/mapper/VolGroupSys-LogVolU01
  /dev/md126
  /dev/sda
  /dev/sdb
  /dev/sdc
  /dev/sdd
  /dev/sde
  /dev/sdf
  /dev/sdg
  /dev/sdh
  /dev/sdi
  /dev/sdj
  /dev/sdk
  /dev/sdl
  /dev/sdm
  /dev/sdn
+------------------------------------+



     =====> os_status_summary

  STATUS TYPE     DETAILS
+---------------+--------------------------------------------------------------------------+
  OS and SYSTEM   .----------------------------------------------------------------------.
                  | #CORES | CACHE    | KERNEL_RELEASE                     | #PROCESSORS |
                  +--------+----------+------------------------------------+-------------+
                  |     12 | 22528 KB | 4.14.35-1902.303.4.1.el7uek.x86_64 |          48 |
                  '--------+----------+------------------------------------+-------------'
  SLEEPING TASK   .----------------------------------.
                  | PID | TASK              | USER   |
                  +-----+-------------------+--------+
                  | 531 | wait_woken        | oracle |
                  | 301 | KsWaitEvent_OSD   | root   |
                  | 267 | worker_thread     | root   |
                  | 217 | do_semtimedop     | oracle |
                  | 192 | smpboot_thread_fn | root   |
                  '-----+-------------------+--------'
  CPU DETAILS     .-------------------------------------------------.
                  | IDLE_TIME | SWAP_USED | LOAD | TASKS | MEM_USED |
                  +-----------+-----------+------+-------+----------+
                  |      94.4 |  0.00 %   | 2.44 |  1971 |  59.94 % |
                  '-----------+-----------+------+-------+----------'
+---------------+--------------------------------------------------------------------------+



     =====> os_disk_location

  ID   BLOCKS       BOOT   START   SYSTEM   END         PATH
+----+------------+------+-------+--------+-----------+-----------+
  ee   468845567+   NO         1   GPT      937691135   /dev/sda1
  ee   468845567+   NO         1   GPT      937691135   /dev/sdb1
+----+------------+------+-------+--------+-----------+-----------+



     =====> os_sleeping_tasks

  PID   TASK                    USER
+-----+-----------------------+--------+
  531   wait_woken              oracle
  301   KsWaitEvent_OSD         root
  267   worker_thread           root
  217   do_semtimedop           oracle
  192   smpboot_thread_fn       root
  112   rescuer_thread          root
   64   kthread_parkme          root
   38   do_semtimedop           grid
   22   pipe_wait               grid
   20   poll_schedule_timeout   root
+-----+-----------------------+--------+



     =====> system_configuration

|                                               System configuration                                              |
+-----------+-------------+----------+------------------------------------------+-------+----------+--------------+
  Frequency   #Processors   Hostname   Model_name                                 Cores   Cache      Vendor
+-----------+-------------+----------+------------------------------------------+-------+----------+--------------+
   3100.005            48   nodeabc    Intel(R) Xeon(R) Gold 5218 CPU @ 2.30GHz      12   22528 KB   GenuineIntel
+-----------+-------------+----------+------------------------------------------+-------+----------+--------------+



     =====> os_cpu_details

  TYPE           DETAILS
+--------------+-----------------------------------------------------------------------------+
  AVERAGE_LOAD   .------------------------------------------------.
                 | LAST_5_MINUTE | LAST_1_MINUTE | LAST_15_MINUTE |
                 +---------------+---------------+----------------+
                 |          2.95 |          3.55 |           2.44 |
                 '---------------+---------------+----------------'
  TASKS          .------------------------------------------------.
                 | Total | Stopped | Running | Sleeping | Zombies |
                 +-------+---------+---------+----------+---------+
                 |  1971 |      17 |       1 |     1508 |       0 |
                 '-------+---------+---------+----------+---------'
  MEMORY         .-------------------------------------------------------------------------.
                 | Total        | Used         | Percent_Used | Buffers      | Free        |
                 +--------------+--------------+--------------+--------------+-------------+
                 | 39466067+ KB | 23657516+ KB |  59.94 %     | 12640815+ KB | 31677368 KB |
                 '--------------+--------------+--------------+--------------+-------------'
  SWAP           .-------------------------------------------------------------------.
                 | Total       |  | Used | Cached       | Percent_Used | Free        |
                 +-------------+--+------+--------------+--------------+-------------+
                 | 25165820 KB |  | 0 KB | 14715107+ KB |  0.00 %      | 25165820 KB |
                 '-------------+--+------+--------------+--------------+-------------'
  CPU            .----------------------------.
                 | VALUE | TYPE               |
                 +-------+--------------------+
                 |   1.9 | USER_CPU_TIME      |
                 |   1.7 | SYSTEM_CPU_TIME    |
                 |   0.0 | USER_NICE_CPU_TIME |
                 |  94.4 | IDLE_CPU_TIME      |
                 |   2.0 | IO_WAIT_CPU_TIME   |
                 |   0.0 | HARDWARE_IRQ       |
                 |   0.0 | SOFTWARE_IRQ       |
                 |   0.0 | STEAL_TIME         |
                 '-------+--------------------'
+--------------+-----------------------------------------------------------------------------+


  Status Type: Select Status Type - select [status_type_number|status_type_name]
        1 => os_clusterwide_status
        2 => os_nodeabc
        3 => os_nodexyz

tfactl_summary_osoverview>

You can even save your output into an HTML file which is great for a quick view and very easy to present and transfer too. The option to generate report into HTML format is by calling “summary -overview -html” command within TFACTL and use option ‘q’ to save reports from tfactl_summary> CLI.
Let’s see how to do that.

[root@nodeabc ~]#
[root@nodeabc ~]# tfactl
WARNING - AHF Software is older than 180 days. Please consider upgrading AHF to the latest version using ahfctl upgrade.
tfactl> summary -overview -html

  Executing Summary in Parallel on Following Nodes:
    Node : nodeabc
    Node : nodexyz

LOGFILE LOCATION : /u01/app/grid/oracle.ahf/data/repository/suptools/nodeabc/summary/root/20221012121321/log/summary_command_20221012121321_nodeabc_82905.log

  Component Specific Summary collection :
    - Collecting CRS details ... Done.
    - Collecting ASM details ... Done.
    - Collecting ACFS details ... Done.
    - Collecting DATABASE details ... Done.
    - Collecting PATCH details ... Done.
    - Collecting LISTENER details ... Done.
    - Collecting NETWORK details ... Done.
    - Collecting OS details ... Done.
    - Collecting TFA details ... Done.
    - Collecting SUMMARY details ... Done.

  Remote Summary Data Collection : In-Progress - Please wait ...
  - Data Collection From Node - nodexyz .. Done.

  Prepare Clusterwide Summary Overview ... Done
      cluster_status_summary

  COMPONENT   STATUS    DETAILS
+-----------+---------+---------------------------------------------------------------------------------------------------+
  CRS         PROBLEM   .-----------------------------------------------.
                        | CRS_SERVER_STATUS   : ONLINE                  |
                        | CRS_STATE           : ONLINE                  |
                        | CRS_INTEGRITY_CHECK : FAIL                    |
                        | CRS_RESOURCE_STATUS : OFFLINE Resources Found |
                        '-----------------------------------------------'
  ASM         PROBLEM   .-------------------------------------------------------.
                        | ASM_DISK_SIZE_STATUS : WARNING - Available Size < 20% |
                        | ASM_BLOCK_STATUS     : PASS                           |
                        | ASM_CHAIN_STATUS     : PASS                           |
                        | ASM_INCIDENTS        : PASS                           |
                        | ASM_PROBLEMS         : PASS                           |
                        '-------------------------------------------------------'
  ACFS        OFFLINE   .-----------------------.
                        | ACFS_STATUS : OFFLINE |
                        '-----------------------'
  DATABASE    PROBLEM   .-----------------------------------------------------------------------------------------------.
                        | ORACLE_HOME_DETAILS                                                        | ORACLE_HOME_NAME |
                        +----------------------------------------------------------------------------+------------------+
                        | .------------------------------------------------------------------------. | OraDB19000_home1 |
                        | | PROBLEMS | INCIDENTS | DB_BLOCKS | DATABASE_NAME | STATUS  | DB_CHAINS | |                  |
                        | +----------+-----------+-----------+---------------+---------+-----------+ |                  |
                        | | PROBLEM  | PROBLEM   | PASS      | FATDBA1       | PROBLEM | PROBLEM   | |                  |
                        | '----------+-----------+-----------+---------------+---------+-----------' |                  |
                        '----------------------------------------------------------------------------+------------------'
  PATCH       OK        .----------------------------------------------.
                        | CRS_PATCH_CONSISTENCY_ACROSS_NODES      : OK |
                        | DATABASE_PATCH_CONSISTENCY_ACROSS_NODES : OK |
                        '----------------------------------------------'
  LISTENER    OK        .-----------------------.
                        | LISTNER_STATUS   : OK |
                        '-----------------------'
  NETWORK     OK        .---------------------------.
                        | CLUSTER_NETWORK_STATUS :  |
                        '---------------------------'
  OS          OK        .-----------------------.
                        | MEM_USAGE_STATUS : OK |
                        '-----------------------'
  TFA         OK        .----------------------.
                        | TFA_STATUS : RUNNING |
                        '----------------------'
  SUMMARY     OK        .------------------------------------.
                        | SUMMARY_EXECUTION_TIME : 0H:1M:44S |
                        '------------------------------------'
+-----------+---------+---------------------------------------------------------------------------------------------------+


        ### Entering in to SUMMARY Command-Line Interface ###

tfactl_summary>list

  Components : Select Component - select [component_number|component_name]
        1 => overview
        2 => crs_overview
        3 => asm_overview
        4 => acfs_overview
        5 => database_overview
        6 => patch_overview
        7 => listener_overview
        8 => network_overview
        9 => os_overview
        10 => tfa_overview
        11 => summary_overview

tfactl_summary>q

        ### Exited From SUMMARY Command-Line Interface ###

--------------------------------------------------------------------
REPOSITORY  : /u01/app/grid/oracle.ahf/data/repository/suptools/nodeabc/summary/root/20221012121321/nodeabc
HTML REPORT : <REPOSITORY>/report/Consolidated_Summary_Report_20221012121321.html
--------------------------------------------------------------------

tfactl>

This is how the HTML report looks like, the summary TFA report.

Hope It Helped!
Prashant Dixit

Posted in Advanced, troubleshooting | Tagged: | Leave a Comment »

Differences I have noticed in the Query Block Registry section of an execution plan between Oracle 19c and 21c

Posted by FatDBA on October 10, 2022

Hi Guys,

Todays post is a quick one about the difference that I have noticed in one of the extended execution plan section ‘Query block registry‘ between Oracle 19c (19.8) and Oracle 21c (21.3). I am not going to explain about query blocks etc. here as I’ve already made few blog posts on those topics in the past, this one is about the difference that you will observe between two said database versions for QBR section in execution plans.

First I am going to use the option/flag ‘qbregistry‘ (for Query block registry info) in Oracle database version 19.16, and next will repeat same steps in Oracle 21.3. Query block registy information can also be collect from the 10053 optimizer traces, but I always notice that one’s there in CBO traces are more repetitive that what you see as a concise version through execution plans with ‘qbregistry‘ option.

So, I have already set the playground, for testing purpose, created two sample tables and have written two outer join queries. One for each table. Then combining the results of these using union all.

--
-- In Oracle 19.16 Database
--
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Oct 9 03:17:19 2022
Version 19.8.0.0.0

SQL> explain plan for select /*+ GATHER_PLAN_STATISTICS */ *
from   toys, bricks
where  toy_id = brick_id (+)
union all
select *
from   toys, bricks
where  toy_id (+) = brick_id
and    toy_id is null;  

Explained.


SQL> select * from table(dbms_xplan.display('PLAN_TABLE',NULL,'+alias +outline +qbregistry'));

PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 731550672

-------------------------------------------------------------------------------
| Id  | Operation            | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------
|   0 | SELECT STATEMENT     |        |     6 |   354 |     8   (0)| 00:00:01 |
|   1 |  UNION-ALL           |        |       |       |            |          |
|*  2 |   HASH JOIN OUTER    |        |     3 |   177 |     4   (0)| 00:00:01 |
|   3 |    TABLE ACCESS FULL | TOYS   |     3 |    96 |     2   (0)| 00:00:01 |
|   4 |    TABLE ACCESS FULL | BRICKS |     3 |    81 |     2   (0)| 00:00:01 |
|*  5 |   FILTER             |        |       |       |            |          |
|*  6 |    HASH JOIN OUTER   |        |     3 |   177 |     4   (0)| 00:00:01 |
|   7 |     TABLE ACCESS FULL| BRICKS |     3 |    81 |     2   (0)| 00:00:01 |
|   8 |     TABLE ACCESS FULL| TOYS   |     3 |    96 |     2   (0)| 00:00:01 |
-------------------------------------------------------------------------------

Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------

   1 - SET$1
   2 - SEL$1
   3 - SEL$1 / TOYS@SEL$1
   4 - SEL$1 / BRICKS@SEL$1
   5 - SEL$2
   7 - SEL$2 / BRICKS@SEL$2
   8 - SEL$2 / TOYS@SEL$2

Outline Data
-------------

  /*+
      BEGIN_OUTLINE_DATA
      USE_HASH(@"SEL$1" "BRICKS"@"SEL$1")
      LEADING(@"SEL$1" "TOYS"@"SEL$1" "BRICKS"@"SEL$1")
      FULL(@"SEL$1" "BRICKS"@"SEL$1")
      FULL(@"SEL$1" "TOYS"@"SEL$1")
      USE_HASH(@"SEL$2" "TOYS"@"SEL$2")
      LEADING(@"SEL$2" "BRICKS"@"SEL$2" "TOYS"@"SEL$2")
      FULL(@"SEL$2" "TOYS"@"SEL$2")
      FULL(@"SEL$2" "BRICKS"@"SEL$2")
      OUTLINE_LEAF(@"SET$1")
      OUTLINE_LEAF(@"SEL$2")
      OUTLINE_LEAF(@"SEL$1")
      ALL_ROWS
      DB_VERSION('19.1.0')
      OPTIMIZER_FEATURES_ENABLE('19.1.0')
      IGNORE_OPTIM_EMBEDDED_HINTS
      END_OUTLINE_DATA
  */

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - access("TOY_ID"="BRICK_ID"(+))
   5 - filter("TOY_ID" IS NULL)
   6 - access("TOY_ID"(+)="BRICK_ID")

Note
-----
   - dynamic statistics used: dynamic sampling (level=2)

Query Block Registry:
---------------------
<q o="2" f="y"><n><![CDATA[SET$1]]></n><f><h><t><![CDATA[NULL_HALIAS]]></t><s><![CDATA[SET$1]]></s></h></f></q>
<q o="2" f="y"><n><![CDATA[SEL$1]]></n><f><h><t><![CDATA[BRICKS]]></t><s><![CDATA[SEL$1]]></s></h><h><t><![CDATA[TOYS]]></t><s><![CDATA[SEL$1]]> </s></h></f></q>
<q o="2" f="y"><n><![CDATA[SEL$2]]></n><f><h><t><![CDATA[BRICKS]]></t><s><![CDATA[SEL$2]]></s></h><h><t><![CDATA[TOYS]]></t><s><![CDATA[SEL$2]]> </s></h></f></q>

73 rows selected.

SQL>
SQL>

Above ‘Query Block Registry’ XML translates to something like this
SET$1 NULL_HALIAS|SET$1
SEL$1 BRICKS|SEL$1|TOYS|SEL$1
SEL$2 BRICKS|SEL$2|TOYS|SEL$2

Considering we have a two SELECT statements, one for each table, internally optimizer has created two query blocks SEL$1 and SEL$2, one for each of the select. Here its using a hint alias name ‘NULL_HALIAS‘, and points to both of the two SELECT statements used in the original query.

Next, lets execute the same statement in Oracle 21c (21.3.0) version and see the difference in QBR section. 

--
-- In Oracle 21.3 Database
--
-- Skipping few sections to have more clarity about discussed topic
SQL*Plus: Release 21.0.0.0.0 - Production on Sat Oct 8 23:57:12 2022
Version 21.3.0.0.0

SQL>  select * from table(dbms_xplan.display('PLAN_TABLE',NULL,'+alias +outline +qbregistry'));

PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Plan hash value: 731550672
...
.....
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------

   1 - SET$1
   2 - SEL$1
   3 - SEL$1 / "TOYS"@"SEL$1"
   4 - SEL$1 / "BRICKS"@"SEL$1"
   5 - SEL$2
   7 - SEL$2 / "BRICKS"@"SEL$2"
   8 - SEL$2 / "TOYS"@"SEL$2"

Outline Data
-------------
......
Predicate Information (identified by operation id):
---------------------------------------------------
.....

Query Block Registry:
---------------------

  SEL$1 (PARSER) [FINAL]
  SEL$2 (PARSER) [FINAL]
  SET$1 (PARSER) [FINAL]

SQL>

Here with 21c (21.3), first thing is its no more coming in the form of an XML, The curious part out of the entire output is the ‘Query Block Registry‘ where the [FINAL] is the transformation that is chosen by the CBO. This assures that time was used on a query block which has been selected for an optimal plan.

That’s it, just a small tidbit this time! 🙂

Hope It Helped!
Prashant Dixit

Posted in Advanced, troubleshooting | Tagged: , , , , | Leave a Comment »

A cool perl script to generate AWR report time series in any given timeframe …

Posted by FatDBA on October 2, 2022

Hi All,

Recently I was doing an analysis on a slothful database where I had to generate multiple AWR reports to cover almost 12 hours of the problem period. I usually go with few of the SQL scripts or AWR generator tools for my trend analysis, but I was little lucky in making unexpected and fortunate discovery on Metalink, found a cool Doc ID 2857522.1 which explains about an Oracle provided perl script to generate AWR report time series in any given timeframe. The script works with RDBMS 12.1 and later.

The script generates all the AWR reports with [begin snapid:end snapid] equal to [n,n+1] with n falling into a given time interval. The script is very handy and interactive, gives you option to choose between standard Text or HTML format, report type (RAC or Non-RAC type reports). You can call it in both command line or interactive mode.

This script generates a timeseries of awr report for a given database in a awr repository. It connects to database via oracle sid on the db server or via tnsalias. To run the script just execute B . To connect via oracle sid do not specify username password and tnsalias. In order to have sixty minutes time-series reports do not specify frequency if awr snapshot is executed every 60 minutes (default awr setting), set frequency 2 if awr snapshot is executed every 30 mins , 4 if awr snapshot is executed every 15 mins and so on. Leaving frequency blank will generate a series based on the awr snapshot frequency. All reports generated during execution will be saved in dumpdir, if the directory does not exist it will be automatically created.

By default awr reports will be generated in text format. To generate pluggable database awr reports connect to database by specifying username , password and tns alias of the pluggable db.

-- Call perl script awrdmp.pl to run the AWR extraction.
[oracle@fatdba ~]$ perl ./awrdmp.pl 
Enter usrname: - 
Enter password: - 
Enter tnsalias: - 
Enter frequency - 
Enter mode
(text/html) - text
CONNECTED AS SYSDBA  
RDBMS VERSION: 19.0.0.0.0

---- ---------- ------- ---------- ---------- -------------------- ------
NUM       DBID  INSTID     DBNAME     INSTID              MACHINE CONTID
---- ---------- ------- ---------- ---------- -------------------- ------
0 2511273110       2      DIXITD       fat2             racnode2      0
1 2511273110       1      DIXITD       fat1             racnode1      0

Enter database num: [0,1] -: 0
 0 2511273110       2      DIXITD       fat2             racnode2
RANGE AVAILABLE IN REPOSITORY FOR DBID 2511273110 INST 2:
------------------------------------------------------
[191 04-SEP-22 07.58.34.180 AM : 420 05-SEP-22 06.28.18.307 AM] 
Enter the minimum date interval (DD/MM/YYYY) -: 04/09/2022
Enter the maximum date interval (DD/MM/YYYY) -: 05/09/2022
GENERATING FILES
[  12 %] writing file : report_2_DIXITD_191_192.text 



--
--
--
-- In case if want to execute it in command line format.
perl awrdmp.pl --batch --freq 1 --instid 1 --dbid 2511273110  --dbn DIXITD --begin 04/09/2022 --end 05/09/2022 --rac --mode html


--
--
--
-- Output under dumpdir directory.
ls -ltr ./dumpdir
[...]
-rw-r--r-- 1 oracle oinstall 145147 Sep 05 14:16 report_1_DIXITD_196_197.text
-rw-r--r-- 1 oracle oinstall 159775 Sep 05 14:16 report_1_DIXITD_197_198.text
-rw-r--r-- 1 oracle oinstall 157100 Sep 05 14:16 report_1_DIXITD_198_199.text
-rw-r--r-- 1 oracle oinstall 148216 Sep 05 14:16 report_1_DIXITD_199_200.text
-rw-r--r-- 1 oracle oinstall 144003 Sep 05 14:16 report_1_DIXITD_200_201.text
-rw-r--r-- 1 oracle oinstall 146216 Sep 05 14:16 report_1_DIXITD_201_202.text

Hope It Helped
Prashant Dixit

Posted in Advanced, troubleshooting | Tagged: , , , | Leave a Comment »

Are you looking for a method to stop automatic SQL quarantine without disabling the entire SQL Quarantine feature ? Welcome to Oracle 21c …

Posted by FatDBA on September 23, 2022

Hi All,

Recently I was working on a 21c database for a POC where at one point I want to disable automatic creation of SQL Quarantine, but without disabling the entire statement Quarantine feature. This 21.3.0.0.0 Database had got the resource manager enabled, and one of the SQL was taking long time to complete, longer than the allowed directive limits on IO & CPU TIME, and as expected the SQL was killed with message “ORA-00040: active time limit exceeded – call aborted” and the SQL plan was quarantined. I wanted to stop or disable the auto creation of SQL Quarantines for the SQL in question, after RM terminates the SQL.

If you want to read more about SQL Quarantine, please click this link to my earlier post with a demo about it.

I remember in 19c there wasn’t any way to achieve that and can only regulate behavior using two of the underscore parameters _quarantine_enabled or _optimizer_quarantine_sql. Oracle 21c has introduced two two new parameters to control the behavior of SQL Quarantine, and that specially solves this issue.

First one is optimizer_capture_sql_quarantine, if set to FALSE, would disable the automatic creation of SQL Quarantine configurations after RM termination of a SQL query execution. This is FALSE by default.

The second parameter is optimizer_use_sql_quarantine, if set to FALSE would disable the use of existing SQL Quarantine configurations in a database. This parameter determines whether the optimizer considers SQL Quarantine configurations when choosing an execution plan for a SQL statement. This is TRUE by default, thereby allowing users to manually create and use SQL Quarantine configurations.

Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

-- Default Setting
SQL> show parameter OPTIMIZER_CAPTURE_SQL_QUARANTINE

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
optimizer_capture_sql_quarantine     boolean     FALSE
SQL>
SQL>

-- Default Setting
SQL> sho parameter OPTIMIZER_USE_SQL_QUARANTINE

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
optimizer_use_sql_quarantine         boolean     TRUE
SQL>
SQL>

Hope It Helped!
Prashant Dixit

Posted in Uncategorized | Tagged: , , , | Leave a Comment »

FRA full with archives ORA-38706 ORA-38708 ? Not always think of a BUG … And when that proud little DBA in me missed common sense

Posted by FatDBA on September 11, 2022

Hi All,
Some time back I was working on an 19.16 database where I’d to enable FLASHBACK on a database, but immediately kicked out with an error “ORA-38706: Cannot turn on FLASHBACK DATABASE logging. ORA-38708: not enough space for first flashback database log file”. So, I’d tried to expand the FRA size, but thought to check what there inside the FRA, it was 99.9% full with 270 archive log files occupying 99.39% of the total allocated space. So, everything was good till that point.

[oracle@fatdba ~]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Sep 5 19:07:28 2022
Version 19.16.0.0.0

Copyright (c) 1982, 2022, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.16.0.0.0

SQL>
SQL> show parameter db_recovery_file_dest_size

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest_size           big integer 251G


NAME         SPACE_LIMIT_GB SPACE_AVAILABLE_GB PERCENT_FULL
------------ -------------- ------------------ ------------
+RECO                   251         .240234375         99.9


FILE_TYPE               PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES     CON_ID
----------------------- ------------------ ------------------------- --------------- ----------
CONTROL FILE                             0                         0               1          0
REDO LOG                                 0                         0               0          0
ARCHIVED LOG                         99.39                         0             270          0
BACKUP PIECE                           .01                         0               2          0
IMAGE COPY                               0                         0               0          0
FLASHBACK LOG                            0                         0               0          0
FOREIGN ARCHIVED LOG                     0                         0               0          0
AUXILIARY DATAFILE COPY                  0                         0               0          0

But I thought to check space at the ASM Level. I queried v$asm_diskgroup and results were totally opposite with what I saw with V$RECOVERY_FILE_DEST and v$flash_recovery_area_usage. RECO Disk Group (FRA location) was almost 100% free and only 0.54% was consumed. Same results were there when I’d queried RECO DG via asmcmd.

-- results from v$asm_diskgroup view
Disk Group            Sector   Block   Allocation
Name                    Size    Size    Unit Size State       Type   Total Size (MB) Used Size (MB) Pct. Used
-------------------- ------- ------- ------------ ----------- ------ --------------- -------------- ---------
DATA                     512   4,096    1,048,576 CONNECTED   EXTERN         691,197        356,322     51.55
OCRVFDG                  512   4,096    4,194,304 MOUNTED     EXTERN          25,596            100       .39
RECO                     512   4,096    1,048,576 CONNECTED   EXTERN       1,048,575          5,645       .54
                                                                     --------------- --------------
Grand Total:                                                               1,765,368        362,067



ASMCMD> lsdg
State    Type    Rebal  Sector  Logical_Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Voting_files  Name
MOUNTED  EXTERN  N         512             512   4096  1048576    691197   334875                0          334875              0             N  DATA/
MOUNTED  EXTERN  N         512             512   4096  4194304     25596    25496                0           25496              0             N  OCRVFDG/
MOUNTED  EXTERN  N         512             512   4096  1048576   1048575  1043233                0         1043233              0             N  RECO/
ASMCMD>

At this point I’d started thinking about some kind of a BUG in the database, I know about few FRA related bugs in earlier Oracle versions. Just before I’d tried anything else, I thought to execute dbms_backup_restore.refreshagedfiles which refreshes the view. At the same time tried kra_options event which resets v$recovery_file_dest, but no luck 😦

SQL>
SQL> alter session set events 'immediate trace name kra_options level 1';

Session altered.

SQL>  execute dbms_backup_restore.refreshagedfiles;

PL/SQL procedure successfully completed.

SQL>

And right at that point I was very sure it was happening all due to a bug and was thinking to contact Oracle support. But just before that, that proud little DBA in me thought, Am I missing something ? Any other possible areas I should have explored before connecting with OCS ?

I’d checked RMAN to see if it still has any expired archivelog details and ran ‘crosscheck archivelog all’, and it identified exactly 270 older archivelogs which were non existent. So, that proud little DBA was wrong 🙂 .. When the count was matched exactly with the v$flash_recovery_area_usage, I’d deleted all of those expired archivelogs from catalog.

-- To Crosscheck all archivelog files present in the RMAN catalog.
RMAN> crosscheck archivelog all;

using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=258 device type=DISK
validation failed for archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_1.261.1109109619 RECID=1 STAMP=1109109620
validation failed for archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_2.264.1109401205 RECID=2 STAMP=1109401206
validation failed for archived log
.....
........
..........
..............
validation failed for archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_268.463.1114203831 RECID=268 STAMP=1114203829
validation failed for archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_269.469.1114207455 RECID=269 STAMP=1114207454
validation succeeded for archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_321.531.1114624193 RECID=270 STAMP=1114624193
Crosschecked 270 objects


-- Delete expired archivelog files
RMAN>
RMAN>
RMAN> delete expired archivelog all;
...
.......
270     1    270     X 31-AUG-22
        Name: +RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_268.463.1114203831 RECID=268 STAMP=1114203829
..
.......
Do you really want to delete the above objects (enter YES or NO)? YES
deleted archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_1.261.1109109619 RECID=1 STAMP=1109109620
deleted archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_2.264.1109401205 RECID=2 STAMP=1109401206
deleted archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_3.265.1109671797 RECID=3 STAMP=1109671799
deleted archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_4.266.1109955617 RECID=4 STAMP=1109955618
deleted archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_5.267.1110233333 RECID=5 STAMP=1110233334
deleted archived log
archived log file name=+RECO/FATDBA/ARCHIVELOG/2022_07_02/thread_1_seq_6.268.1110485231 RECID=6 STAMP=1110485232
deleted archived log
Deleted 270 EXPIRED objects

RMAN>
RMAN>

And immediately I saw the change in FRA related dynamic views (V$RECOVERY_FILE_DEST and v$flash_recovery_area_usage) and matched the genuine utilization at the ASM level.

[oracle@fatdba ~]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Sep 5 19:07:28 2022
Version 19.16.0.0.0

Copyright (c) 1982, 2022, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.16.0.0.0

SQL>
SQL>
SQL> SELECT NAME,
       (SPACE_LIMIT / 1024 / 1024 / 1024) SPACE_LIMIT_GB,
         ((SPACE_LIMIT - SPACE_USED + SPACE_RECLAIMABLE) / 1024 / 1024 / 1024) AS SPACE_AVAILABLE_GB,
       ROUND((SPACE_USED - SPACE_RECLAIMABLE) / SPACE_LIMIT * 100, 1) AS PERCENT_FULL
  FROM V$RECOVERY_FILE_DEST;  

NAME         SPACE_LIMIT_GB SPACE_AVAILABLE_GB PERCENT_FULL
------------ -------------- ------------------ ------------
+RECO                   200          197.59082          1.2

SQL> select * from v$flash_recovery_area_usage;

FILE_TYPE               PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES     CON_ID
----------------------- ------------------ ------------------------- --------------- ----------
CONTROL FILE                           .01                         0               1          0
REDO LOG                                 0                         0               0          0
ARCHIVED LOG                           .57                         0               2          0
BACKUP PIECE                           .01                       .01               2          0
IMAGE COPY                               0                         0               0          0
FLASHBACK LOG                            0                         0               0          0
FOREIGN ARCHIVED LOG                     0                         0               0          0
AUXILIARY DATAFILE COPY                  0                         0               0          0

8 rows selected.

Hope It Helped!
Prashant Dixit

Posted in Uncategorized | Tagged: , , | Leave a Comment »

A new 21c dynamic view securefile_shrink, and possibly a new BUG in 21.3. I guess I have identified a BUG

Posted by FatDBA on September 1, 2022

Recently I was doing a POC on Oracle 21c, and I had to shrink an LOB secure file column, and I was aware about a new dynamic view added to Oracle 21c called V$SECUREFILE_SHRINK, which is very useful to monitor securefiles shrink operations. This gives you some great details like start time, end time, status of the operation etc. I shrank one of the required securefile LOB column of a table and I was interested to see what all was captured by V$SECUREFILE_SHRINK … But It was empty!! got ‘no rows selected’, Why is that ??

Let me try to replicate the scenario and explain what I was doing that day.

-- Let me create a test scenario
-- Will create a brand new playground to test all things
[oracle@witnessalberta ~]$ !sq
sqlplus / as sysdba

SQL*Plus: Release 21.0.0.0.0 - Production on Sun Aug 28 10:50:26 2022
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

SQL>
SQL>
SQL>
SQL> CREATE PLUGGABLE DATABASE pdb2 ADMIN USER pdb_adm IDENTIFIED BY oracle90 CREATE_FILE_DEST='/opt/oracle/oradata';

Pluggable database created.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 ORCLPDB1                       MOUNTED
         4 PDB2                           MOUNTED
SQL> ALTER PLUGGABLE DATABASE pdb2 OPEN READ WRITE;

Pluggable database altered.

SQL>  ALTER SESSION SET CONTAINER = PDB2;

Session altered.

SQL> SHOW CON_NAME;

CON_NAME
------------------------------
PDB2

SQL>
SQL> conn fatdba/oracle90@PDB2
Connected.
SQL>
SQL>
SQL>
SQL> show user
USER is "FATDBA"
SQL>
SQL>
SQL>
SQL>

-- Created a Table with a SECUREFILE LOB 
SQL> CREATE TABLE secure_file_tab (rid  NUMBER(5), bcol BLOB) LOB (bcol) STORE AS SECUREFILE bcol_lob 
(TABLESPACE users DISABLE  STORAGE IN ROW CHUNK 8192 RETENTION MIN 3600 KEEP_DUPLICATES NOCOMPRESS DECRYPT CACHE READS); 

Table created.

SQL>

SQL>
-- Inserted some 100000 random rows into the table
insert into secure_file_tab VALUES(101, utl_raw.cast_to_raw('hello, this is the first review'));
insert into secure_file_tab VALUES(101, utl_raw.cast_to_raw('hello, this is the first review'));
insert into secure_file_tab VALUES(101, utl_raw.cast_to_raw('hello, this is the first review'));
insert into secure_file_tab VALUES(101, utl_raw.cast_to_raw('hello, this is the first review'));
insert into secure_file_tab VALUES(101, utl_raw.cast_to_raw('hello, this is the first review'));
insert into secure_file_tab VALUES(101, utl_raw.cast_to_raw('hello, this is the first review'));
...
......
........

SQL> select count(*) from secure_file_tab;

  COUNT(*)
----------
    100001

SQL>
SQL>
-- Lets check the size of the table.
SQL> select segment_name, bytes/1024 from dba_segments where segment_name='SECURE_FILE_TAB';

SEGMENT_NAME         BYTES/1024
-------------------- ----------
SECURE_FILE_TAB      4096

-- Have deleted all rows from the table
SQL> delete from secure_file_tab where RID=101;

100000 rows deleted.

SQL> COMMIT;

SQL> select count(*) from secure_file_tab;

COUNT(*)
----------
1

-- Gathered table stats
SQL> exec dbms_stats.gather_table_stats(null, 'secure_file_tab');

PL/SQL procedure successfully completed.


SQL> select segment_name, bytes/1024 from dba_segments where segment_name='SECURE_FILE_TAB';

SEGMENT_NAME         BYTES/1024
-------------------- ----------
SECURE_FILE_TAB      113



SQL> alter table secure_file_tab modify lob(bcol) (shrink space);

Table altered.

Now time to check if anything captured in the v$securefile_shrink or gv$securefile_shrink dynamic view about the securefile shrink operation.

-- Lets check if anything captured by the view
SQL> desc v$securefile_shrink
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 LOB_OBJD                                           NUMBER
 SHRINK_STATUS                                      VARCHAR2(40)
 START_TIME                                         TIMESTAMP(3) WITH TIME ZONE
 END_TIME                                           TIMESTAMP(3) WITH TIME ZONE
 BLOCKS_MOVED                                       NUMBER
 BLOCKS_FREED                                       NUMBER
 BLOCKS_ALLOCATED                                   NUMBER
 EXTENTS_ALLOCATED                                  NUMBER
 EXTENTS_FREED                                      NUMBER
 EXTENTS_SEALED                                     NUMBER
 CON_ID                                             NUMBER


SQL> select * from v$securefile_shrink;

no rows selected

SQL> select * from gv$securefile_shrink;

no rows selected

SQL>

Nothing!!! Why ? Why ? Let me try the other way (MOVE LOB) and see if that populates anything in v$securefile_shrink or gv$securefile_shrink. Repopulated the same table again with 100000 rows, deleted all rows from the table, committed changes, regathered stats and verified table size, same what we did in Test 1.

-- Changed the LOB SHRINK technique this time.
SQL> ALTER TABLE secure_file_tab MOVE LOB(BCOL) STORE AS (TABLESPACE test);

Table altered.


-- Lets check if anything captured by the view
SQL> select * from v$securefile_shrink;

no rows selected

SQL> select * from gv$securefile_shrink;

no rows selected

SQL>

Nothing!!! Why ? Why ? Let me try the with one more way (SHRINK SPACE CASCADE) again and see if that populates anything in v$securefile_shrink or gv$securefile_shrink. Repopulated the same table again with 100000 rows, deleted all rows from the table, committed changes, regathered stats and verified table size, same what we did in Test 1.

--Let me try the other way
SQL> alter table secure_file_tab MODIFY LOB(BCOL) (SHRINK SPACE CASCADE);

Table altered.

-- Lets check if anything captured by the view
SQL> select * from v$securefile_shrink;

no rows selected

SQL> select * from gv$securefile_shrink;

no rows selected

SQL>

Nothing!!! Why ? Why ? This is super strange now. Then finally, I decided to check with Oracle support and asked them to try at their end in 21c and from their end also it was getting populated. I guess I have identified a BUG in 21.3.0.0.0!! 🙂 🙂 Currently the case is with development team and they are taking a look on this buggy behavior on Oracle 21.5 on Red Hat Linux 7 x86_64 … Let’s see how it goes from here, will post the solution or the cause behind this ill behavior soon.

Hope It Helped!
Prashant Dixit

Posted in Advanced, troubleshooting | Tagged: , , , , | Leave a Comment »

‘Error rendering element. Exception: ORA-00942: table or view does not exist’ with OEM 13c Information Publisher Reports

Posted by FatDBA on August 20, 2022

Hi Guys,

Recently while working on a custom OEM 13c Information Publisher Report to automate monitoring production database I’d encountered an error which says “Error rendering element. Exception: ORA-00942: table or view does not exist” while previewing an underlying custom SQL. The SQL was a join between multiple OEM repository views (mgmt$target_properties, gc_metric_values, mgmt_targets, mgmt$db_datafiles, mgmt$metric_current, mgmt$db_init_params etc.) and throws an error whenever I tried to run the code. Interestingly the SQL working absolutely when I ran it directly on the OEM repository database, but failed when I tried to call the same SQL via Information report on OEM.

I was confused as I was connected with the SYSMAN, passing the same SQL which I’d tested on OMS database directly, all OMS logs were clean, then why its failing for Information Reports. Though from error it was evident that those objects belongs to another schema but I was already connected using SYSMAN in OEM …

I did a quick test to verify if this the reason. As a test ran this simple query as a report first from the EM reports.

select target_name,target_type from mgmt_targets where target_name ='FATDB';

Next, I tried from the repo and granted SELECT ON privilege on mgmt_target view to report owner MGMT_VIEW, and re ran the query, and this time it worked 🙂

SQL> Grant SELECT ON mgmt_targets to MGMT_VIEW;

So, the reason was, the Information Publisher reports uses the MGMT_VIEW user to generate reports and MGMT_VIEW has privileges to access the MGMT$ views only. This is an account used by Oracle Enterprise Manager Database Control for reports. As my custom SQL referenced multiple non-MGMT$ views i.e. gc_metric_values & mgmt_targets and hence failed to recognize them and needs permissions to read data from those views.

Hope It Helped!
Prashant Dixit

Posted in troubleshooting | Tagged: , | Leave a Comment »

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