.
This section contains detailed guidance
for evaluating each section of an AWR report. The data
in an AWR report is the delta, or changes, between the
accumulated metrics within each snapshot. Reading an
AWR report id difficult because most of the metrics are
undocumented because the AWR report was originally designed
for Oracle support internal-use only.
Report Summary:
This gives an overall summary of the instance during the
snapshot period, and it contains important aggregate summary
information.
Cache Sizes (end):
This shows the size of each SGA region after AMM has changed
them. This information can be compared to the original
init.ora
parameters at the end of the AWR report.
Load Profile:
This important section shows important rates expressed in
units of per second and transactions per second.
Instance Efficiency
Percentages:
With a target of 100%, these are high-level ratios for
activity in the SGA.
Shared Pool Statistics:
This is a good summary of changes to the shared pool during
the snapshot period.
Top 5 Timed Events:
This is the most important section in the AWR report. It
shows the top wait events and can quickly show the overall
database bottleneck.
Wait Events Statistics
Section: This
section shows a breakdown of the main wait events in the
database including foreground and background database wait
events as well as time model, operating system, service, and
wait classes statistics.
Wait Events:
This AWR report section provides more detailed wait event
information for foreground user processes which includes Top
5 wait events and many other wait events that occurred
during the snapshot interval.
Background Wait Events:
This section is relevant to the background process wait
events.
Time Model Statistics:
Time mode statistics report how database-processing time is
spent. This section contains detailed timing information on
particular components participating in database processing.
Operating System Statistics:
The stress on the Oracle server is important, and this
section shows the main external resources including I/O,
CPU, memory, and network usage.
Service Statistics:
The service statistics section gives information about how
particular services configured in the database are
operating.
SQL Section:
This section displays top SQL, ordered by important SQL
execution metrics.
SQL
Ordered by Elapsed Time: Includes SQL
statements that took significant execution time during
processing.
SQL
Ordered by CPU Time: Includes SQL statements
that consumed significant CPU time during its processing.
SQL
Ordered by Gets: These SQLs performed a high
number of logical reads while retrieving data.
SQL
Ordered by Reads: These SQLs performed a high
number of physical disk reads while retrieving data.
SQL
Ordered by Parse Calls: These SQLs experienced
a high number of reparsing operations.
SQL
Ordered by Sharable Memory: Includes SQL
statements cursors which consumed a large amount of SGA
shared pool memory.
SQL
Ordered by Version Count: These SQLs have a
large number of versions in shared pool for some reason.
Instance Activity Stats:
This section contains statistical information describing how
the database operated during the snapshot period.
Instance
Activity Stats (Absolute Values): This section
contains statistics that have absolute values not derived
from end and start snapshots.
Instance
Activity Stats (Thread Activity): This report
section reports a log switch activity statistic.
I/O Section:
This section shows the all important I/O activity for the
instance and shows I/O activity by tablespace, data file,
and includes buffer pool statistics.
Tablespace IO Stats
File IO Stats
Buffer Pool Statistics
Advisory Section:
This section show details of the advisories for the buffer,
shared pool, PGA and Java pool.
Buffer Pool Advisory
PGA Aggr Summary: PGA Aggr Target Stats; PGA Aggr Target
Histogram; and PGA Memory Advisory.
Shared Pool Advisory
Java Pool Advisory
Buffer Wait Statistics:
This important section shows buffer cache waits statistics.
Enqueue Activity:
This important section shows how enqueue operates in the
database. Enqueues are special internal structures which
provide concurrent access to various database resources.
Undo Segment Summary:
This section gives a summary about how undo segments are
used by the database.
Undo Segment Stats:
This section shows detailed history information about undo
segment activity.
Latch Activity:
This section shows details about latch statistics. Latches
are a lightweight serialization mechanism that is used to
single-thread access to internal Oracle structures.
Latch Sleep Breakdown
Latch Miss Sources
Parent Latch Statistics
Child Latch Statistics
Segment Section:
This report section provides details about hot segments
using the following criteria:
Segments
by Logical Reads: Includes top segments which
experienced high number of logical reads.
Segments
by Physical Reads: Includes top segments which
experienced high number of disk physical reads.
Segments
by Buffer Busy Waits: These segments have the
largest number of buffer waits caused by their data blocks.
Segments
by Row Lock Waits: Includes segments that had
a large number of row locks on their data.
Segments
by ITL Waits: Includes segments that had a
large contention for Interested Transaction List (ITL). The
contention for ITL can be reduced by increasing INITRANS
storage parameter of the table.
Dictionary Cache Stats:
This section exposes details about how the data dictionary
cache is operating.
Library Cache Activity:
Includes library cache statistics describing how shared
library objects are managed by Oracle.
SGA Memory Summary:
This section provides summary information about various SGA
regions.
init.ora
Parameters:
This section shows the original init.ora
parameters for the instance during the snapshot period.
