Oracle 8i Internal Services for Waits, Latches, Locks, and Memory
by Steve Adams


Following are the changes made in the 1/01 reprint.


Here's a key to the markup:

        [page-number]: serious technical mistake
        {page-number}: minor technical mistake
        <page-number>: important language/formatting problem
        (page-number): language change or minor formatting problem
        ?page-number?: reader question or request for clarification


(10)  Changed the Tip to a regular paragraph, and inserted it above the 
"Scheduling Latencies" heading.  Also, changed "The semaphore parameters..." 
to "Note that the semaphore parameters..."


<13>  Inserted the following Warning above the "Wait Types" heading:

        "Bug 918002 can inhibit SQL statement sharing and cause latch 
        contention in release 8.1.5 if TIMED_STATISTICS or SQL_TRACE are used. 
        Bug 1210242 can cause the same performance problem under release 8.1.6 
        if both facilities are used concurrently."


{17}  In the second line of the center column in the table at the bottom of 
the page, changed "V$SYSTEM_EVENT" to "V$SESSION_EVENT".


{18}  In the second line of the center column in the table at the top of 
the page, changed "V$SESSION_EVENT" to "V$SYSTEM_EVENT".


<30>  Replaced the end of the paragraph at the top of the page, from the 
sentence beginning "That statistic represents...", with the following text 
(note that terms in single quotes should be in italics):

        "That statistic represents the number of times that a process missed 
        on this latch while holding another latch. For example, the 
        WAITS_HOLDING_LATCH statistic for the 'redo allocation' latch counts 
        both 'spin gets' and 'sleep gets' against the 'redo allocation' latch 
        while holding another latch such as a 'cache buffers chains' latch."


{34}  The description for LAST_WAIT_POSTING (in the "Parameters" section) did
read: 

        "latch wait posting is enabled for the library cache and shared pool
        latches only." 

Now reads: 

        "latch wait posting is enabled for library cache, library cache load, 
        and shared pool latches only."


(34)  The description for _SPIN_YIELD_CPU_FREQ did read:

        "...on multi-processor machines."

Now reads:

        "...on most multi-processor machines."


{35}  The description for waits holding latch did read:

        "The number of times that a process waited on any event while holding
        the latch"

Now reads:

        "The number of misses while holding another latch"


{51}  In Table 4-5, changed "2 shared" to "3 shared" and "3 exclusive" to 
"5 exclusive".


{96}  The following sentence has been added at the end of the first full
paragraph:

        "Note that from release 8.1.6 there are many more free lists in the 
        shared pool, and thus 'shared pool' latch contention is no longer a 
        major problem."


(98)  In the 4th line of the last paragraph, changed "never" to "seldom" 
(occurs twice in the line).


<99>  The last sentence of the first paragraph (starting with "Nevertheless, 
large chunks...") has been deleted.


{102}  The last line on the page did read:

        "* Parallel Query Option (PQO)"

Now reads:

        "* Parallel Execution (PX)--formerly Parallel Query Option (PQO)"


(colophon)  The first sentence of the fifth paragraph did read:

        "Ellie Volkenhausen designed the cover of this book..."

Now reads:

        "Ellie Volckhausen designed the cover of this book..."