Creating a multiname SSL cert

1. install openSSL
2. generate a private key
openssl genrsa -out key.pem 1024
3. make a conf file. the main idea of which is to have the multiple commonName and have the subjectAltName = DNS:domain in the req_extensions.
contents:
[ req ]
default_bits = 1024
default_keyfile = key.pem
distinguished_name = req_distinguished_name
req_extensions = v3_ca
x509_exentions = v3_ca

[ req_distinguished_name ]
countryName = Your Country
countryName_default = EE
stateOrProvinceName = State/Province
stateOrProvinceName_default = Harjumaa
localityName = Locality
localityName_default = Tallinn
organizationName = Organization
organizationName_default = OЬ JOT Eesti
organizationalUnitName = Organizational Unit
organizationalUnitName_default = OЬ JOT Eesti
emailAddress = e-mail
emailAddress_default = syse@elektrobit.com
0.commonName = Common Name (eg, YOUR name)
0.commonName_default = intranet
0.commonName_max = 64
1.commonName = Common Name (eg, YOUR name)
1.commonName_default = intranet.ee.ebgroup.elektrobit.com
1.commonName_max = 64

[ v3_ca ]
subjectAltName = DNS:intranet, DNS:intranet.ee.ebgroup.elektrobit.com


4. generate a request 4 CA
openssl req -new -config cert.conf -out cert.req
4.1. feed the cert.req to the CA
5. retrive the base64 encoded cert
6. generate a p12 file for importing it to the server
openssl pkcs12 -export -in intranetb64.cer -inkey key.pem -out intra.p12 -name "JOT Eesti Intranet"
7. at the webserver open the certificate mmc snapin for Computer and import the p12 file into the Personal storage
8. apply the installed cert to the website using the IIS snapin.

Gathering statistics

If database was created using DBCA, an automatic statistics gathering procedure should be already set up. It can be observed under the Scheduler jobs. You need to be logged in as "sys as sysdba" to see it.

To gather statistics manually you can use the ANALYZE SQL command, or DBMS_STATS package. You can also use EM, but that's just an interface for the DBMS_STATS.

When gathering statistics you can use the COMPUTE or ESTIMATE option. COMPUTE will gather fill stats when ESTIMATE will only take a representative sample of the rows in the table thus performing faster but not guaranteeing maximum correctness like COMPUTE does.

Gathering stats using the DBMS_STATS
Summary of DBMS_STATS subprograms

Most frequently needed are:
GATHER_DATABASE_STATS
GATHER_FIXED_OBJECTS_STATS
GATHER_INDEX_STATS
GATHER_SCHEMA_STATS
GATHER_TABLE_STATS

There is also a "DELETE_%" procedure corresponding to each "GATHER_%' procedure.

It is also possible to EXPORT and IMPORT statistics. You could have several different sets of statistics for different purposes.

Monitoring and Advisors

In 10g statistics are gathered automatically by background processes MMON (memory monitor) and MMNL (memory monitor light). By default every 60 minutes MMON wakes up and saves the statistics out of the dictionary views into AWR (automatic workload repository).

AWR data is owned by user SYSMAN and stored in SYSAUX tablespace.

Amount of statistics gathered is defined by parameter statistics_level
There are three possible options:
BASIC - practically disables statistics gathering, very few is saved.
TYPICAL - standard level
ALL - same as TYPICAL but also keeps the execution plans and timing information from the operating system

The statistics are kept in AWR for 7 days by default.

To change the collection interval and retention period DBMS_WORKLOAD_REPOSITORY package can be used. Like this:

exec dbms_workload_repository.modify_snapshot_settings(interval=>90,retention=>8640);

This sets interval to 90 minutes and retention to 8640 minutes (this makes 6 days or something)

After the statistics snapshot is taken, a process named ADDM (automatic database diagnostic monitoring) analyzes newly gathered information and compares it with two previously taken snapshots. By comparing these three, it can identify potential performance problems and suggest possible remedies. The main goal is to minimize the DBTime, which is being CPU and WAIT time put together for non-idle database users.

To get the list of snapshots:

SELECT * FROM dba_hist_snapshot;

To take snapshot manually:

EXECUTE dbms_workload_repository.create_snapshot('TYPICAL');

To delete snapshots:

exec dbms_workload_repository.drop_snapshot_range(begin_snap_id, end_snap_id);

To get a text ADDM report:

@?/rdbms/admin/addmrpt.sql

Additionally the following views can be queried to get the ADDM findings: DBA_ADVISOR_FINDINGS, DBA_ADVISOR_OBJECTS, DBA_ADVISOR_RECOMMENDATIONS, DBA_ADVISOR_RATIONALE

There is also a number of special-purpose advisors which include:

• SQL Tuning Advisor

Analyzes SQL (recent or from the AWR). SQLs can be combined into SETs and whole SETs sent for analysis.

• SQL Access Advisor
  

Analyzes SQL from the schema point of view. Suggests creating indexes and maetrialized views.

• Memory Advisor

Advises on 3 memory parameters: buffer cache, shared pool, and PGA. In case of buffer cache performance measure is "relative change in physical reads". For shared pool "relative change in parse time savings" is used and for PGA it is the "cache hit %".

• Mean Time To Recover Advisor

Here you only set the desired recovery time in seconds and oracle sets a number of internal parameters to make the recovery time as close as possible to your desired value.

• Segment Advisor

Finds segments which can be shrunk and thus to release the unused space back to the tablespace. After finding the segements worth shrinking, following SQLs are executed:

alter table "SCOTT"."T2" enable row movement;
alter table "SCOTT"."T2" shrink space;

• Undo Management Advisor

Analyzes the UNDO generation rates and suggests a correct retention time and undo tablespace size.

Locking

Reference: Types of locks.

Developers Guide - Locking Data explicitly

Metalink Doc ID: Note:15476.1 FAQ about Detecting and Resolving Locking Conflicts

SQL*Plus script to query locks information

Locks can be: DML, DDL or internal
There are two basic types of DML locks: row locks and table locks.

Types of tables locks:
ROW SHARE (RS) - obtained when SELECT ... FOR UPDATE is issued. At least this is what Oracle documentation says. Testing shows that when SELECT FOR UPDATE is used, an RX locks is obtained. So it seems that... I don't know ;)

Basically this type of lock needed to show that some data is going to be changed in this table so that no other transaction could drop or modify the table or obtain a EXCLUSIVE lock.

ROW EXCLUSIVE (RX) - same as previous but it also prohibits other transactions to lock the table in SHARE and SHARE ROW EXCLUSIVE modes. It is set automatically when DML statements (such as update) are used against the table.
This seems fair since SHARE lock is needed to prohibit any updates, then it is fair that an update is prohibiting the SHARE lock to be obtained.

SHARE (S) - prohibits others to obtain RS, RX locks thus preventing a table to be updated while SHARE lock is active. This is needed if table level read consistency needs to be reached. Other sessions can also obtain SHARE locks at the same time. If two or more transactions will try to update the table while having the SHARE lock on, this will result in a deadlock even if they update different rows. If you need to get the read consistent table plus an exclusive right to update it, use the SHARE ROW EXCLUSIVE lock.
I also noticed that if after obtaining a SHARE lock, try to update the table, lock type is automatically converted into SHARE ROW EXCLUSIVE type. This is logical because you cannot update the table until others are holding the SHARE lock, you have to get the SHARE + ROW EXCLUSIVE lock type to do that.
Note:This lock is automatically obtained when CREATE INDEX statement is run.

SHARE ROW EXCLUSIVE (SRX) - prohibits all other locks to be obtained, except for the RS lock. So this is almost exclusive lock. You get both read consistency and exclusive right to update the table. Oracle docs say that others still can issue the SELECT .. FOR UPDATE statement on this table but my test show that this is not true...

EXCLUSIVE - this one has to be obtained before all of the DDL stuff can be executed.