(in general, Oracle does not recommend playing with hidden parameters. Check with Oracle support when in doubt).
[Oracle Database] Data Pump Export in a RAC environment fails with ORA-31693, ORA-31617, ORA-19505, ORA-27037 errors
ORA-31693: Table data object "<SCHEMA>"."<TABLE>":"P_1147" failed to load/unload \
and is being skipped due to error:
ORA-31617: unable to open dump file "<FILE>" for write
ORA-19505: failed to identify file "<FILE>"
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
Add CLUSTER=N to the list of existing expdp options.
[Solaris, ZFS] Check the current ARC size and its breakdown
The Diagnostic Framework in FMW 11g environments detect, diagnose and resolve critical errors such as uncaught exceptions, deadlocked threads and out of memory errors. It is enabled by default.
Though DFW is supposed to diagnose and fix some of the issues transparently, due to the inevitable bugs in [all kinds of] software and misconfigurations, sometimes DFW itself may become a major issue. For instance, there is a bug that reported very high system CPU time on a SPARC server where FMW 11g was running. Per the bug description, the system CPU utilization spikes every minute exactly at 00s of a minute, CPU utilization goes down within few seconds - but the pattern persists and the spiky behavior returns within a minute. Another symptom was the sudden drop in available swap space from tens of giga bytes to a few mega bytes when the CPU spike occurs. Upon close examination, it was found out that DFW in FMW is forking tens of jstack processes to collect the thread dumps from an equal number of java processes running in that FMW environment, causing the sudden spike in CPU (each process is busy gathering thread dumps at the same time) and a steep drop in swap space (each jstack process forked a jmap process. both jstack and jmap processes consume some virtual memory just like any other process). All this happened because DFW thought it found a critical issue, and it wasn't noticed or addressed by anyone including the administrators (DFW couldn't fix this particular issue on its own) - so, it kept gathering the diagnostic data continuously. In this example, DFW did the right thing but the diagnostic data collection frequency was too short - only one minute, that diminished the value of DFW and made it a liability. In such dire situations, probably it is best to disable the dump sampling feature of Diagnostic Framework tentatively while the underlying original issue is being fixed in that application environment. It can be enabled again when the critical issue was fixed, and no longer an issue.
[Solaris 11] Virtual-to-physical link (NIC) mapping
Check the output of /sbin/dladm show-phys(any user). By default, only those physical links that are available on the running system are displayed. Option -P shows the physical device and attributes of all physical links.
$ /sbin/dladm show-phys
LINK MEDIA STATE SPEED DUPLEX DEVICE
net0 Ethernet up 1000 full ixgbe0
net5 Infiniband down 0 unknown ibp2
net1 Ethernet up 1000 full ixgbe1
net6 Infiniband down 0 unknown ibp3
net4 Ethernet up 10 full usbecm2
$ /sbin/dladm show-phys -P
LINK DEVICE MEDIA FLAGS
net8 ibp1 Infiniband r----
net0 ixgbe0 Ethernet -----
net7 ibp0 Infiniband r----
net3 ixgbe3 Ethernet r----
net5 ibp2 Infiniband -----
net1 ixgbe1 Ethernet -----
net6 ibp3 Infiniband -----
net4 usbecm2 Ethernet -----
net2 vsw0 Ethernet r----
(1) AWR report shows bogus wait events and times on SPARC T5 servers
Here is a sample from one of the Oracle 11g R2 databases running on a SPARC T5 server with Solaris 11.1 SRU 7.5
Top 5 Timed Foreground Events
Avg wait (ms)
% DB time
latch: cache buffers chains
library cache: mutex X
buffer busy waits
latch: In memory undo latch
Reason: Unknown. There is a pending bug 17214885 - Implausible top foreground wait times reported in AWR report.
Tentative workaround: Disable power management as shown below.
# poweradm set administrative-authority=none
# svcadm disable power
# svcadm enable power
Verify the setting by running poweradm list.
Also disable NUMA I/O object binding by setting the following parameter in /etc/system (requires a system reboot).
Oracle Solaris 11 added support for NUMA I/O architecture. Here is a brief explanation of NUMA I/O from Solaris 11 : What's New web page.
Non-Uniform Memory Access (NUMA) I/O : Many modern systems are based on a NUMA architecture, where each CPU or set of CPUs is associated with its own physical memory and I/O devices. For best I/O performance, the processing associated with a device should be performed close to that device, and the memory used by that device for DMA (Direct Memory Access) and PIO (Programmed I/O) should be allocated close to that device as well. Oracle Solaris 11 adds support for this architecture by placing operating system resources (kernel threads, interrupts, and memory) on physical resources according to criteria such as the physical topology of the machine, specific high-level affinity requirements of I/O frameworks, actual load on the machine, and currently defined resource control and power management policies.
Do not forget to rollback these changes after applying the fix for the database bug 17214885, when available.
(2) Redo logs on F40 PCIe cards(non-volatile flash storage)
Per the F40 PCIe card user's guide, the Sun Flash Accelerator F40 PCIe Card is designed to provide best performance for data transfers that are multiples of 8k size, and using addresses that are 8k aligned. To achieve optimal performance, the size of the read/write data should be an integer multiple of this block size and the data transferred should be block aligned. I/O operations that are not block aligned and that do not use sizes that are a multiple of the block size may suffer performance degration, especially for write operations.
Oracle redo log files default to a block size that is equal to the physical sector size of the disk, typically 512 bytes. And most of the time, database writes to the redo log in a normal functioning environment. Oracle database supports a maximum block size of 4K for redo logs. Hence to achieve optimal performance for redo write operations on F40 PCIe cards, tune the environment as shown below.
[Solaris only][F20] To enable maximum throughput from the MPT driver, append the following line to /kernel/drv/mpt.conf and reboot the system.
This tip is applicable to all kinds of flash storage that Oracle sells or sold including F20/F40 PCIe cards and F5100 storage array. sd-config-list in sd.conf may need some adjustment to reflect the correct vendor id and product id.
A NULL value for SCHEMA recompiles all invalid objects in the database.
2. SGA breakdown in Solaris Locality Groups (lgroup)
To find the breakdown, execute pmap -L | grep shm. Then separate the lines that are related to each locality group and sum up the value in 2nd column to arrive at a number that shows the total SGA memory allocated in that locality group.
(I'm pretty sure there will be a much easier way that I am not currently aware of.)
3. Default values for shared pool, java pool, large pool, ..
If the *pool parameters were not set explicitly, executing the following query is one way to find out what are they currently set to.
SQL> select * from v$sgainfo;
NAME BYTES RES
-------------------------------- ---------- ---
Fixed SGA Size 2171296 No
Redo Buffers 373620736 No
Buffer Cache Size 8.2410E+10 Yes
Shared Pool Size 1.7180E+10 Yes
Large Pool Size 536870912 Yes
Java Pool Size 1879048192 Yes
Streams Pool Size 268435456 Yes
Shared IO Pool Size 0 Yes
Granule Size 268435456 No
Maximum SGA Size 1.0265E+11 No
Startup overhead in Shared Pool 2717729536 No
Free SGA Memory Available 0
12 rows selected.
4. Fix to PLS-00201: identifier 'GV$SESSION' must be declared error
Grant select privilege on gv_$SESSION to the owner of the database object that failed to compile.
SQL> alter package OWF_MGR.FND_SVC_COMPONENT compile body;
Warning: Package Body altered with compilation errors.
SQL> show errors
Errors for PACKAGE BODY OWF_MGR.FND_SVC_COMPONENT:
390/22 PL/SQL: Item ignored
390/22 PLS-00201: identifier 'GV$SESSION' must be declared
SQL> grant select on gv_$SESSION to OWF_MGR;
SQL> alter package OWF_MGR.FND_SVC_COMPONENT compile body;
Package body altered.
5. Solaris Critical Thread (CT) optimization for Oracle logwriter (lgrw)
Critical Thread is a new scheduler optimization available in Oracle Solaris releases Solaris 10 Update 10 and later versions. Latency sensitive single threaded components of software such as Oracle database's logwriter benefit from CT optimization.
On a high level, LWPs marked as critical will be granted more exclusive access to the hardware. For example, on SPARC T4 and T5 systems, such a thread will be assigned exclusive access to a core as much as possible. CT optimization won't delay scheduling of any runnable thread in the system.
Critical Thread optimization is enabled by default. However the users of the system have to hint the OS by marking a thread or two "critical" explicitly as shown below.
From database point of view, logwriter (lgwr) is one such process that can benefit from CT optimization on Solaris platform. Oracle DBA's can either make the lgwr process 'critical' once the database is up and running, or can simply patch the 18.104.22.168 database software by installing RDBMS patch 12951619 to let the database take care of it automatically. I believe Oracle 12c does it by default. Future releases of 11g software may make lgwr critical out of the box.
Those who install the database patch 12951619 need to carefully follow the post installation steps documented in the patch README to avoid running into unwanted surprises.
6. ORA-14519 error while importing a table from a Data Pump export dump
All partitions in table XYZ are using 32K blocks whereas the implicit default partition is pointing to a 8K block tablespace. Workaround is to use the REMAP_TABLESPACE option in Data Pump impdp command line to remap the implicit default tablespace of the partitioned table to the tablespace where the rest of partitions are residing.
7. Index building task in Data Pump import process
When Data Pump import process is running, by default, index building is performed with just one thread, which becomes a bottleneck and causes the data import process to take a long time especially if many large tables with millions of rows are being imported into the target database. One way to speed up the import process execution is by skipping index building as part of data import task with the help of EXCLUDE=INDEX impdp command line option. Extract the index definitions for all the skipped indexes from the Data Pump dump file as shown below.
Assembler (as) is not installed by default on Solaris 11.
Find and install
# pkg search assembler
INDEX ACTION VALUE PACKAGE
pkg.fmri set solaris/developer/assembler pkg:/firstname.lastname@example.org
# pkg install pkg:/developer/assembler
Assembler binary used to be under /usr/ccs/bin directory on Solaris 10 and prior versions.
There is no /usr/ccs/bin on Solaris 11. Contents were moved to /usr/bin
2. Non-interactive retrieval of the entire list of disks that format reports
If the format utility cannot show the entire list of disks in a single screen on stdout, it shows some and prompts user to - hit space for more or s to select - to move to the next screen to show few more disks. Run the following command(s) to retrieve the entire list of disks in a single shot.
format < /dev/null
echo "\n" | format
3. Finding system wide file descriptors/handles in use
Run the following kstat command as any user (privileged or non-privileged).
kstat -n file_cache -s buf_inuse
Going through /proc (process filesystem) is less efficient and may lead to inaccurate results due to the inclusion of duplicate file handles.
4. ssh connection to a Solaris 11 host fails with error Couldn't agree a client-to-server cipher (available: aes128-ctr,aes192-ctr,aes256-ctr,arcfour128,arcfour256,arcfour)
Solution: add 3des-cbc to the list of accepted ciphers to sshd configuration file.
The focus of the paper is on databases and zones. On SuperCluster, customers have the choice of running their databases in logical domains that are dedicated to running Oracle Database 11g R2. With exclusive access to Exadata Storage Servers, those domains are aptly called "Database" domains. If the requirement mandates, it is possible to create and use all logical domains as "database domains" or "application domains" or a mix of those. Since the focus is on databases, the paper talks only about the database domains and how zones can be created, configured and used within each database domain for fine grained control over multiple databases consolidated in a SuperCluster environment.
When multiple databases are being consolidated (including RAC databases) in database logical domains, zones are one of the options that fulfill requirements such as the fault, operation, network, security and resource isolation, multiple RAC instances in a single logical domain, separate identity and independent manageability for database instances.
The best practices cover the following topics. Some of those are applicable to standalone, non-engineered environments as well.
CPU, memory and disk space allocation
Zone Root on Sun ZFS Storage Appliance
Use of DISM
Use of ZFS filesystem
SuperCluster specific zone deployment tool, ssc_exavm
Exadata Storage Grid (Disk Group) Configuration
Disk Group Isolation
Shared Storage approach
Dedicated Storage Server approach
Resizing Grid Disks
Oracle RAC Configuration Securing the Databases, and
Example Database Consolidation Scenarios
Consolidation example using Half-Rack SuperCluster
Consolidation example using Full-Rack SuperCluster
A large group of experts reviewed the material and provided quality feedback. Hence they deserve credit for their work and time. Listed below are some of those reviewers (sincere apologies if I missed listing any major contributors).
Kesari Mandyam, Binoy Sukumaran, Gowri Suserla, Allan Packer, Jennifer Glore, Hazel Alabado, Tom Daly, Krishnan Shankar, Gurubalan T, Rich long, Prasad Bagal, Lawrence To, Rene Kundersma, Raymond Dutcher, David Brean, Jeremy Ward, Suzi McDougall, Ken Kutzer, Larry Mctintosh, Roger Bitar, Mikel Manitius
Just like the Siebel 8.1.x/SPARC T4 benchmark post, this one too was overdue for at least four months. In any case, I hope the Oracle BI customers already knew about the OBIEE 11g/SPARC T4 benchmark effort. In here I will try to provide few additional / interesting details that aren't covered in the following Oracle PR that was posted on oracle.com on 09/30/2012.
The entire BI middleware stack including the WebLogic 11g Server, OBI Server, OBI Presentation Server and Java Host was installed and configured on a single SPARC T4-4 server consisting four 8-Core 3.0 GHz SPARC T4 processors (total #cores: 32) and 128 GB physical memory. Oracle Solaris 10 8/11 is the operating system.
BI users were authenticated against Oracle Internet Directory (OID) in this benchmark - hence OID software which was part of Oracle Identity Management 22.214.171.124.0 was also installed and configured on the system under test (SUT). Oracle BI Server's Query Cache was turned on, and as a result, most of the query results were cached in OBIS layer, that resulted in minimal database activity making it ideal to have the Oracle 11g R2 database server with the OBIEE database running on the same box as well.
Oracle BI database was hosted on a Sun ZFS Storage 7120 Appliance. The BI Web Catalog was under a ZFS/zpool on a couple of SSDs.
In this benchmark, 25000 concurrent users assumed five different business user roles -- Marketing Executive, Sales Representative, Sales Manager, Sales Vice-president, and Service Manager. The load was distributed equally among those five business user roles. Each of those different BI users accessed five different pre-built dashboards with each dashboard having an average of five reports - a mix of charts, tables and pivot tables - and returning 50-500 rows of aggregated data. The benchmark test scenario included drilling down into multiple levels from a table or chart within a dashboard. There is a 60 second think time between requests, per user.
BI Setup & Test Results
OBIEE 11g 126.96.36.199.0 was deployed on SUT in a vertical scale-out fashion. Two Oracle BI Presentation Server processes, one Oracle BI Server process, one Java Host process and two instances of WebLogic Managed Servers handled 25,000 concurrent user sessions smoothly. This configuration resulted in a sub-second overall average transaction response time (average of averages over a duration of 120 minutes or 2 hours). On average, 450 business transactions were executed per second, which triggered 750 SQL executions per second.
It took only 52% of CPU on average (~5% system CPU and rest in user land) to do all this work to achieve the throughput outlined above. Since 25,000 unique test/BI users hammered different dashboards consistently, not so surprisingly bulk of the CPU was spent in Oracle BI Presentation Server layer, which took a whopping 29%. BI Server consumed about 10-11% and the rest was shared by Java Host, OID, WebLogic Managed Server instances and the Oracle database.
So, what is the key take away from this whole exercise?
SPARC T4 rocks Oracle BI world. OBIEE 11g/SPARC T4 is an ideal combination that may work well for majority of OBIEE deployments on Solaris platform. Or in marketing jargon - The excellent vertical and horizontal scalability of the SPARC T4 server gives customer the option to scale up as well as scale out growth, to support large BI EE installations, with minimal hardware investment.
Evaluate and decide for yourself.
[Credit to our colleagues in Oracle FMW PSR, ISVe teams and SCA lab support engineers]