Carlos Sierra's Tools and Tips

Tools and Tips for Oracle Performance and SQL Tuning

eAdam 3.0

leave a comment »

Source: eAdam 3.0

Written by Carlos Sierra

April 16, 2017 at 7:10 pm

Posted in General

eDB360 meets eAdam 3.0 – when two heads are better than one!

with one comment

Version v1711 of eDB360 invites eAdam 3.0 to the party. What does it mean? We recently learned that eDB360 v1706 introduced the eDB360 repository, which materialized the content of 26 core DBA_HIST views into a staging repository made of heap tables. This in order to expedite the execution of eDB360 on a database with an enlarged AWR. New version v1711 expands the list from 26 views to a total of 219. And these 219 views include now DBA_HIST, DBA, GV$ and V$.

Expanding existing eDB360 repository 8.4x from 26 to 219 views is not what is key on version v1710. The real impact of the latest version of eDB360 is that now it benefits of eAdam 3.0, providing the same benefits of the 219 views of the eDB360 heap-tables repository, but using External Tables, which are easily transported from a source database to a target database. This simple fact opens many doors.

Using the eAdam 3.0 repository from eDB360, we can now extract the metadata from a production database, then restore it on a staging database where we can produce the eDB360 report for the source database. We could also use this new external repository for: finer-granularity data mining; capacity planning; sizing for potential hardware refresh; provisioning tools; to estimate candidate segments for partitioning or for offloading into Hadoop; etc.

With the new external-tables eAdam 3.0 repository, we could easily build a permanent larger heap-table permanent repository for multiple databases (multiple tenants), or for multiple time versions of the same database. Thus, now that eDB360 has met eAdam 3.0, the combination of these two enables multiple innovative future features (custom or to be packaged and shipped with eDB360).

eDB360 recap

eDB360 is a free tool that gives a 360-degree view of an Oracle database. It installs nothing on the database, and it runs on 10g to 12c Oracle databases. It is designed for Linux and UNIX, but runs well on Windows as well (you may want to install first UNIX Utilities UnxUtils and a zip program, else a few OS commands may not properly work on Windows). This repository-less version is the default way to use eDB360, and is the right method for most cases. But now, in addition to the default use, eDB360 can also make use of one of two repositories.

eDB360 takes time to execute (several hours). It is designed to time-out after 24 hours by default. First reason for long execution times is the intentional serial-processing method used, with sequential execution of query after query, while consuming little resources. Such serial execution, plus the fact that it is common to have the tool execute on large databases where the state of AWR is suboptimal, causes the execution to take long.  We often discover that source AWR repositories lack expected partitioning, and in many cases they hold years of data instead of expected 8 to 31 days. Therefore, the nature of serial-execution combined with enlarged and suboptimal AWR repositories, usually cause eDB360 to execute for many hours more than expected. With 8 to 31 days of AWR data, and when such reasonable history is well partitioned, eDB360 usually executes in less than 6 hours.

To overcome the undesired extended execution times of eDB360, and besides the obvious (partition and purge AWR), the tool provides the capability to execute in multiple threads splitting its content by column. And now, in addition to the divide-and-conquer approach of column execution, eDB360 provides 2 repositories with different objectives in mind:

  1. eDB360 repository: Use this method to create a staging repository based on heap tables inside the source database. This method helps to expedite the execution of eDB360 by at least 10x. Repository heap-tables are created and consumed inside the same database.
  2. eAdam3 repository: Use this method to generate a repository based on external tables on the source database. Such external-tables repository can be moved easily to a remote target system, allowing to efficiently generate the eDB360 report there. This method helps to reduce computations in the source database, and enables potential data mining on the external repository without any resources impact on the source database. This method also helps to build other functions on top of the 219-tables repository.

Views included on both eDB360 and eAdam3 repositories:

  1. dba_2pc_neighbors
  2. dba_2pc_pending
  3. dba_all_tables
  4. dba_audit_mgmt_config_params
  5. dba_autotask_client
  6. dba_autotask_client_history
  7. dba_cons_columns
  8. dba_constraints
  9. dba_data_files
  10. dba_db_links
  11. dba_extents
  12. dba_external_tables
  13. dba_feature_usage_statistics
  14. dba_free_space
  15. dba_high_water_mark_statistics
  16. dba_hist_active_sess_history
  17. dba_hist_database_instance
  18. dba_hist_event_histogram
  19. dba_hist_ic_client_stats
  20. dba_hist_ic_device_stats
  21. dba_hist_interconnect_pings
  22. dba_hist_memory_resize_ops
  23. dba_hist_memory_target_advice
  24. dba_hist_osstat
  25. dba_hist_parameter
  26. dba_hist_pgastat
  27. dba_hist_resource_limit
  28. dba_hist_seg_stat
  29. dba_hist_service_name
  30. dba_hist_sga
  31. dba_hist_sgastat
  32. dba_hist_snapshot
  33. dba_hist_sql_plan
  34. dba_hist_sqlstat
  35. dba_hist_sqltext
  36. dba_hist_sys_time_model
  37. dba_hist_sysmetric_history
  38. dba_hist_sysmetric_summary
  39. dba_hist_sysstat
  40. dba_hist_system_event
  41. dba_hist_tbspc_space_usage
  42. dba_hist_wr_control
  43. dba_ind_columns
  44. dba_ind_partitions
  45. dba_ind_statistics
  46. dba_ind_subpartitions
  47. dba_indexes
  48. dba_jobs
  49. dba_jobs_running
  50. dba_lob_partitions
  51. dba_lob_subpartitions
  52. dba_lobs
  53. dba_obj_audit_opts
  54. dba_objects
  55. dba_pdbs
  56. dba_priv_audit_opts
  57. dba_procedures
  58. dba_profiles
  59. dba_recyclebin
  60. dba_registry
  61. dba_registry_hierarchy
  62. dba_registry_history
  63. dba_registry_sqlpatch
  64. dba_role_privs
  65. dba_roles
  66. dba_rsrc_consumer_group_privs
  67. dba_rsrc_consumer_groups
  68. dba_rsrc_group_mappings
  69. dba_rsrc_io_calibrate
  70. dba_rsrc_mapping_priority
  71. dba_rsrc_plan_directives
  72. dba_rsrc_plans
  73. dba_scheduler_job_log
  74. dba_scheduler_jobs
  75. dba_scheduler_windows
  76. dba_scheduler_wingroup_members
  77. dba_segments
  78. dba_sequences
  79. dba_source
  80. dba_sql_patches
  81. dba_sql_plan_baselines
  82. dba_sql_plan_dir_objects
  83. dba_sql_plan_directives
  84. dba_sql_profiles
  85. dba_stat_extensions
  86. dba_stmt_audit_opts
  87. dba_synonyms
  88. dba_sys_privs
  89. dba_tab_cols
  90. dba_tab_columns
  91. dba_tab_modifications
  92. dba_tab_partitions
  93. dba_tab_privs
  94. dba_tab_statistics
  95. dba_tab_subpartitions
  96. dba_tables
  97. dba_tablespace_groups
  98. dba_tablespaces
  99. dba_temp_files
  100. dba_triggers
  101. dba_ts_quotas
  102. dba_unused_col_tabs
  103. dba_users
  104. dba_views
  105. gv$active_session_history
  106. gv$archive_dest
  107. gv$archived_log
  108. gv$asm_disk_iostat
  109. gv$database
  110. gv$dataguard_status
  111. gv$event_name
  112. gv$eventmetric
  113. gv$instance
  114. gv$instance_recovery
  115. gv$latch
  116. gv$license
  117. gv$managed_standby
  118. gv$memory_current_resize_ops
  119. gv$memory_dynamic_components
  120. gv$memory_resize_ops
  121. gv$memory_target_advice
  122. gv$open_cursor
  123. gv$osstat
  124. gv$parameter
  125. gv$pga_target_advice
  126. gv$pgastat
  127. gv$pq_slave
  128. gv$pq_sysstat
  129. gv$process
  130. gv$process_memory
  131. gv$px_buffer_advice
  132. gv$px_process
  133. gv$px_process_sysstat
  134. gv$px_session
  135. gv$px_sesstat
  136. gv$resource_limit
  137. gv$result_cache_memory
  138. gv$result_cache_statistics
  139. gv$rsrc_cons_group_history
  140. gv$rsrc_consumer_group
  141. gv$rsrc_plan
  142. gv$rsrc_plan_history
  143. gv$rsrc_session_info
  144. gv$rsrcmgrmetric
  145. gv$rsrcmgrmetric_history
  146. gv$segstat
  147. gv$services
  148. gv$session
  149. gv$session_blockers
  150. gv$session_wait
  151. gv$sga
  152. gv$sga_target_advice
  153. gv$sgainfo
  154. gv$sgastat
  155. gv$sql
  156. gv$sql_monitor
  157. gv$sql_plan
  158. gv$sql_shared_cursor
  159. gv$sql_workarea_histogram
  160. gv$sysmetric
  161. gv$sysmetric_summary
  162. gv$sysstat
  163. gv$system_parameter2
  164. gv$system_wait_class
  165. gv$temp_extent_pool
  166. gv$undostat
  167. gv$waitclassmetric
  168. gv$waitstat
  169. v$archive_dest_status
  170. v$archived_log
  171. v$ash_info
  172. v$asm_attribute
  173. v$asm_client
  174. v$asm_disk
  175. v$asm_disk_stat
  176. v$asm_diskgroup
  177. v$asm_diskgroup_stat
  178. v$asm_file
  179. v$asm_template
  180. v$backup
  181. v$backup_set_details
  182. v$block_change_tracking
  183. v$cell_config
  184. v$cell_state
  185. v$controlfile
  186. v$database
  187. v$database_block_corruption
  188. v$datafile
  189. v$flashback_database_log
  190. v$flashback_database_stat
  191. v$instance
  192. v$io_outlier
  193. v$iostat_file
  194. v$kernel_io_outlier
  195. v$lgwrio_outlier
  196. v$log
  197. v$log_history
  198. v$logfile
  199. v$mystat
  200. v$nonlogged_block
  201. v$option
  202. v$parallel_degree_limit_mth
  203. v$parameter
  204. v$pdbs
  205. v$recovery_area_usage
  206. v$recovery_file_dest
  207. v$restore_point
  208. v$rman_backup_job_details
  209. v$rman_output
  210. v$segstat
  211. v$spparameter
  212. v$standby_log
  213. v$sys_time_model
  214. v$sysaux_occupants
  215. v$system_parameter2
  216. v$tablespace
  217. v$tempfile
  218. v$thread
  219. v$version

Instructions to use eDB360 and eAdam3 repositories

Both repositories are implemented under the edb360-master/repo subdirectory. Each has a readme file, which explains how to create the repository, consume it and drop it. The eAdam3 repository also includes instructions how to clone an external-table-based eAdam repository into a heap-table-based eDB360 repository.

Executing eDB360 on the eDB360 repository is faster than executing it on the eAdam3 repository, while avoiding new bug 25802477. This new Oracle database bug inflicts compressed external-tables like the ones used by the eAdam3 repository.

If you use eDB360 or eAdam3 repositories and have questions or concerns, do not hesitate to contact the author.


Written by Carlos Sierra

April 10, 2017 at 2:41 pm

“ORA-00997: illegal use of LONG datatype” on a CTAS querying a view with a LONG column

with one comment

Working on the new eDB360 repository I came across this “ORA-00997: illegal use of LONG datatype” while trying to CTAS on the following DBA views:


All these views above include at least a LONG column, which raises the ORA-00997 while trying to do something like: CREATE TABLE edb360.dba#constraints AS SELECT * FROM dba_constraints.

I found several blogs explaining reason and some providing some hints, like using the TO_LOB function. Based on that I created a new stand-alone script that inputs 4 parameters and performs the CTAS I need. The 4 parameters are:

1: owner of source table/view
2: source table/view name
3: owner of target table
4: target table name

I am making this free script available for others to use at will.

-- How to solve ORA-00997: illegal use of LONG datatype while copying tables
-- paramaters
-- 1: owner of source table/view
-- 2: source table/view name
-- 3: owner of target table
-- 4: target table name
-- sample: @repo_edb360_create_one sys dba_constraints edb360 dba#constraints

DEF owner_source = '&1.';
DEF table_source = '&2.';
DEF owner_target = '&3.';
DEF table_target = '&4.';

l_list_ddl VARCHAR2(32767);
l_list_sel VARCHAR2(32767);
l_list_ins VARCHAR2(32767);
FOR i IN (SELECT column_name, data_type, data_length FROM dba_tab_columns WHERE owner = UPPER(TRIM('&&owner_source.')) and table_name = UPPER(TRIM('&&table_source.')) ORDER BY column_id)
l_list_ddl := l_list_ddl||','||i.column_name||' '||REPLACE(i.data_type,'LONG','CLOB');
l_list_ins := l_list_ins||','||i.column_name;
IF i.data_type IN ('VARCHAR2', 'CHAR', 'RAW') THEN
l_list_ddl := l_list_ddl||'('||i.data_length||')';
IF i.data_type = 'LONG' THEN
l_list_sel := l_list_sel||',TO_LOB('||i.column_name||')';
l_list_sel := l_list_sel||','||i.column_name;
EXECUTE IMMEDIATE 'CREATE TABLE &&owner_target..&&table_target. ('||TRIM(',' FROM l_list_ddl)||') COMPRESS';
EXECUTE IMMEDIATE 'INSERT /*+ APPEND */ INTO &&owner_target..&&table_target. ('||TRIM(',' FROM l_list_ins)||') SELECT '||TRIM(',' FROM l_list_sel)||' FROM &&owner_source..&&table_source.';

Written by Carlos Sierra

April 3, 2017 at 11:51 am

Posted in edb360, Scripts

eDB360 new features (March 2017)

with 2 comments

As many of you know, eDB360 is a free tool that provides a 360-degree view of an Oracle database without any installation. A new version is available like once per month, but occasionally a large number of enhancements are implemented at once. This new release v1708 (March 25, 2017) includes several new features requested recently by some users of the tool, thus the need to blog about what is new:

  1. Reducing the scope of eDB360 is now possible without having to generate a custom configuration file. Prior to this version, if a user wanted to generate output for let’s say AWR reports only (section 7a), the tool needed a custom.sql file with line DEF edb360_sections = ‘7a’;. Then we would pass to edb360.sql as 2nd execution parameter the name of this custom configuration file (too cumbersome!). Starting on v1708, we can directly pass to edb360.sql the section that we desire (i.e. SQL> @edb360 T 7a). This 2nd parameter can either input the name of a custom configuration file (legacy functionality), but now it also accepts a column, a section, a list of columns or a list of sections; for example: 7a, 7, 7a-7b, 1-4 and 3 are all valid values.
  2. A couple of reports were added to section 3h: “SQL in logon storms” and “SQL executed row-by-row”. The former identifies those SQL statements that are seen frequently on very short-lived sessions (based on ASH), and the latter presents a list of SQL statements with large number of executions and small number of rows processed.
  3. eDB360 now extracts ASH from eAdam for top 16 SQL_ID (as per SQLd360 list) + top 12 SNAP_ID (as per AWR MAX from column 7a). What it means is that eDB360 includes now a tar file with raw ASH data for both: SQL statements of interest and for AWR periods of interest (both according to what eDB360 considers important). Using eAdam is easy, so when content of eDB360 does not include a very specific aggregation of ASH data that we need, or when we have to understand the sequence of some ASH samples for example, we can then restore this eAdam data on any Oracle database and data mine it.
  4. Some reports on section 2b show now totals at the bottom. That is to SUM some numeric values. Other reports may follow in future releases.
  5. RMAN section includes now a new report “Blocks with Corruption or Non-logged”.
  6. Added Load Profile (Per Sec, Per Txn and Count) as per DBA_HIST_SYSMETRIC_SUMMARY. This Load Profile resembles what we see on AWR at the top, but this is computed for the entire period of diagnostics (31 days by default). It shows max values, average, median and several percentiles. With this new report on section 1a, we can glance over it and discover in minutes some areas of further interest, for example: logons per second too high, just to mention one.
  7. There is a new section 4i with “Waits Count v.s. Average Latency for top 24 Wait Events”. With this set of 24 reports (one for each of the top wait events) we can observe if patterns on the number of counts relate to patterns on the latency for such wait event; for example we are able to see if an increase in the number of waits for db file sequential reads correlates to an increase of average latency for such wait event. We can also observe cases were latency for a wait event cannot be explained by load on current database, thus hinting an external influence.
  8. Fixed “ORA-01476: divisor is equal to zero” on planx at DBA_HIST_SQLSTAT.
  9. Added AWR DIFF reports for RAC and per instance. These are computed comparing MAX reports to MEDIAN reports, and they help to quickly identify large differences on load. These new AWR DIFF reports are regulated by configuration parameter edb360_conf_incl_addm_rpt (enabled by default). They exist on 11R2 and higher.
  10. Added the ASH Analytics Active report for 12c. This new ASH report is regulated by configuration parameter edb360_conf_incl_ash_analy_rpt (enabled by default). This applies to 12c and higher.
  11. The name of the database is now part of the main filename. Some users requested to include this database name as part of the main zip file since they are using eDB360 periodically on several databases. This new feature is regulated by configuration parameter edb360_conf_incl_dbname_file (disabled by default).
  12. At completion, main eDB360 zip file can now by automatically moved to a location other than the standard SQL*Plus working directory. All output files are still generated on the local SQL*Plus directory from where the script edb360.sql is executed (i.e. edb360-master directory), but at the completion of the execution the consolidated output zip file is now moved to a location specified by a new parameter. This new feature is regulated by configuration parameter edb360_move_directory (disabled by default).
  13. Added new report on “Database and Schema Triggers” under column 3h. This new report can be used to see potential LOGON or other global triggers. For triggers on specific tables, refer to SQLd360 which is automatically included on eDB360 for top SQL.
  14. All queries executed by eDB360 to generate its output were modified. New format is q'[query]’. Reason for this change is to improve readability of the code.

Always download and use the latest version of this tool. For questions or feedback email me. And I hope you get to enjoy eDB360 as much as I do!

Written by Carlos Sierra

March 25, 2017 at 6:51 pm

eDB360 includes now an optional staging repository

with 6 comments

eDB360 has always worked under the premise “no installation required”, and still is the case today – it is part of its fundamental essence: give me a 360-degree view of my Oracle database with no installation whatsoever. With that in mind, this free tool helps sites that have gone to the cloud, as well as those with “on-premises” databases; and in both cases not installing anything certainly expedites diagnostics collections. With eDB360, you simply connect to SQL*Plus with an account that can select from the catalog, execute then a set of scripts behind eDB360 and bingo!, you get to understand what is going on with your database just by navigating the html output. With such functionality, we can remotely diagnose a database, and even elaborate on the full health-check of it. After all, that is how we successfully use it every day!, saving us hundreds of hours of metadata gathering and cross-reference analysis.

Starting with release v1706, eDB360 also supports an optional staging repository of the 26 AWR views listed below. Why? the answer is simple: improved performance! This can be quite significant on large databases with hundreds of active sessions, with frequent snapshots, or with a long history on AWR. We have seen cases where years of data are “stuck” on AWR, specially in older releases of the database. Of course cleaning up the outdated AWR history (and corresponding statistics) is highly recommended, but in the meantime trying to execute edb360 on such databases may lead to long execution hours and frustration, taking sometimes days for what should take only a few hours.

  1. dba_hist_active_sess_history
  2. dba_hist_database_instance
  3. dba_hist_event_histogram
  4. dba_hist_ic_client_stats
  5. dba_hist_ic_device_stats
  6. dba_hist_interconnect_pings
  7. dba_hist_memory_resize_ops
  8. dba_hist_memory_target_advice
  9. dba_hist_osstat
  10. dba_hist_parameter
  11. dba_hist_pgastat
  12. dba_hist_resource_limit
  13. dba_hist_service_name
  14. dba_hist_sga
  15. dba_hist_sgastat
  16. dba_hist_sql_plan
  17. dba_hist_sqlstat
  18. dba_hist_sqltext
  19. dba_hist_sys_time_model
  20. dba_hist_sysmetric_history
  21. dba_hist_sysmetric_summary
  22. dba_hist_sysstat
  23. dba_hist_system_event
  24. dba_hist_tbspc_space_usage
  25. dba_hist_wr_control
  26. dba_hist_snapshot

Thus, if you are contemplating executing eDB360 on a large database, and provided pre-check script edb360-master/sql/awr_ash_pre_check.sql shows that eDB360 might take over 24 hours, then while you clean up your AWR repository you can use the eDB360 staging repository as a workaround to speedup eDB360 execution. The use of this optional staging repository is very simple, just look inside the edb360-master/repo directory for instructions. And as always, shoot me an email or comment here if there were any questions.

Written by Carlos Sierra

February 19, 2017 at 8:43 pm

eDB360 takes long to execute!

leave a comment »

eDB360 provides a lot of insight about an Oracle database. It executes thousands of SQL statements querying GV$ and DBA views from the Oracle’s data dictionary. It was designed to impose very little load on the system where it executes, thus it consumes only one session and avoids parallel execution. On a system where the state of historical metrics is “normal”, eDB360 may take one or two hours to execute. In the other hand, when the volume of historical metrics is abnormally “large”, then eDB360 may execute for many hours up to default threshold of 24, then quit. No worries here, it can be restarted pretty much where it left…

If you are considering executing eDB360 on one of your databases, before you do please execute first a light-weight “pre-check”, which is basically a small script that reports on the state of Active Session History (ASH) stored into the Automatic Workload Repository (AWR). Bare in mind that ASH and AWR are part of the Oracle Diagnostics Pack, so consider such “pre-check” only if you have a license for such Oracle Pack for the target database.

AWR ASH Pre-Check

You can execute stand-alone the awr_ash_pre_check.sql script available as free software in GitHub within edb360-master or cscripts-master. If downloading eDB360, you can find awr_ash_pre_check.sql under the edb360-master/sql directory, and if you download the cscripts set, then you can find awr_ash_pre_check.sql under cscripts-master/sql.

This pre-check script reports on the following potential concerns:

  1. Retention period of AHR, frequency of Snapshots, AWR Baselines, and similar.
  2. Age of CBO Statistics on the main table behind DBA_HIST_ACTIVE_SESS_HISTORY (WRH$_ACTIVE_SESSION_HISTORY) and its partitions.
  3. State of CBO Statistics for WRH$_ACTIVE_SESSION_HISTORY segments: Are the statistics Locked? Are they Stale?
  4. Size of WRH$_ACTIVE_SESSION_HISTORY segments, with range of Snapshots per segment (partition). Are they outside the desired retention window?
  5. Creation date and last DDL date for WRH$_ACTIVE_SESSION_HISTORY segments. So expected partition splitting can be verified.

Take for example result below. It shows that current ASH repository contains 320.6 days of history, even when in this case only 30 were requested (displayed on an upper part of report not shown here). We also see ASH is 16.4 GBs in size, where normally 1-2 GBs are plenty. We can conclude last partition split (or simply last DDL) is 289.7 days old, where normally only a few days-old are expected. This pre-check sample results on a ballpark estimate of 127 hours to execute eDB360. In other words, if we had one month of history (as current AWR configuration requests) instead of 320.6 days of history, then ASH repository would be less than 10% its current size and eDB360 would be estimated to execute in about 13 hours instead of 127. Keep in mind this “pre-check” provides a ballpark estimate, so an actual execution of eDB360 would take more or less the estimated time.


What to do if eDB36o is estimated to run for several days like in sample above? What I recommend is to fix ASH first. This process requires to read and digest at least 3 My Oracle Support (MOS) notes below, but it is not as bad as it sounds. You want to follow this path anyways, so any diagnostics tool that relies on ASH from AWR would benefit of the much needed cleanup.

  1. WRH$_ACTIVE_SESSION_HISTORY Does Not Get Purged Based Upon the Retention Policy (Doc ID 387914.1)
  2. Bug 14084247 – ORA-1555 or ORA-12571 Failed AWR purge can lead to continued SYSAUX space use (Doc ID 14084247.8)
  3. Manually Purge the Optimizer Statistics and AWR Snaphots to Reduce Space Usage of SYSAUX Tablespace (Doc ID 1965061.1)

Diagnosing eDB360 taking long

Let’s say you executed an older version of eDB360 and it took long (newer versions starting on v1620 perform an automatic pre-check, and if execution is estimated to last more than 8 hours, then it pauses and ask for confirmation before executing). If you executed an older version of eDB360, or simply your execution took longer than expected, review next the following files included on the directory from where you executed eDB360 (edb360-master), or stored within the edb360_*.zip file generated by eDB360 as it executed.

  1. awr_ash_pre_check_<database_name>.txt
  2. verify_stats_wr_sys_<database_name>.txt
  3. 00002_edb360_<NNNNNN>_log.txt
  4. 00003_edb360_<NNNNNN>_log2.txt
  5. 00004_edb360_<NNNNNN>_log3.txt
  6. 00005_edb360_157536_tkprof_sort.txt

If you find one of the SQL statements from eDB360 is taking more than a few minutes to execute, suspect first outdated CBO statistics on the Data Dictionary objects behind such query. Or if volume of data accessed by such query from eDB360 is large, suspect AWR data not getting purged. In either case take action accordingly.

If you cannot make sense of the information provided by these diagnostics files above, then contact eDB360 author at

Keep in mind that execution time for eDB360 really depends on the state of several metrics stored in AWR, where ASH is the most relevant piece but not the only one. Think outdated statistics and outdated metrics!

Written by Carlos Sierra

November 23, 2016 at 5:47 pm

Posted in General

Smart Scans efficiency chart for Oracle Engineered Systems

with one comment

If you manage an Oracle Engineered System you may wonder how well your Smart Scans are performing. Are you taking full advantage of Exadata Optimizations? If so, how do you measure them?

Uwe Hesse explains well some important statistics on Exadata. For some time now, eDB360 includes a report on Smart Scan efficiency, which is nothing but a Google Chart on top of relevant statistics.

Sample chart below is from a data warehouse DW application. It shows in blue that bytes eligible for offloading are around 95%, which denote a large amount of desired full scans. We see in red that between 80 and 95% of the expected I/O did not hit the network, i.e. it was saved (incorrectly referred as IO Saved since what is saved is the network traffic). And in yellow we see between 30 and 45% of the IO was entirely avoided due to Storage Indexes. So, with 80-95% of the expected data not going through the network and 30-45% of IO entirely eliminated, I could conclude that Exadata Optimizations are well applied on this DW.


If you have SQL*Plus access to an Engineered System, and want to produce a chart like this, simply download and execute free tool eDB360. This tool installs nothing on your database!

Written by Carlos Sierra

November 8, 2016 at 10:26 am

Posted in edb360, Exadata, Tools