Sybase 12.4.2 manual Temporary buffer cache message, Controlling message logging, 189

	CHAPTER 5 Moving Data In and Out of Databases
Table 5-4: Main IQ Store file message
Item	Description
Main: I: L#	Number of logical file reads.
P#	Number of physical file reads.
O: D#	Number of times a buffer was destroyed.
P#	Number of physical writes.
C: D#	Buffer manager data compression ratio. This is the total number of
	bytes eligible for compression minus number of bytes used after
	compression divided by total number of bytes eligible for
	compression times 100. In other words, it tells how much data was
	compressed (what percentage it is of its uncompressed size). The
	larger the number, the better. Only certain data blocks are eligible for
	compression. Eligible blocks include indexes, (90-95% of a
	database) and Sort sets. This reflects only data compression
	techniques used by the buffer manager. Other data compression may
	take place before data reaches the buffer manager, so the total data
	compression may be higher.

In general, assuming the buffer cache is full, you should have between 10 and 1000 logical reads per physical read. A lower value indicates excessive thrashing in the buffer manager. More than 1000 times larger can indicate that you may be overallocating memory to your buffer cache. If either of these conditions exists, see Chapter 12, “Managing System Resources” for information on setting buffer cache sizes, or Chapter 13, “Monitoring and Tuning Performance” for information on using the IQ performance monitor.

Temporary buffer cache message

These lines display information about the Temp buffer cache.

Temporary I: L25240/P8 O: D4749/P0 C:D0

See the description for the Main buffer cache message above.

Controlling message logging

The Notify_Modulus database option adjusts the default frequency of notification messages during loads, or omit these message. See the chapter “Database Options” in the Adaptive Server IQ Reference Manual for details. The NOTIFY option in the LOAD command overrides the Notify_Modulus setting.

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