Oracle Redo Log Buffer size settings

Redo Log BufferThe size is determined by the initialization parameters.LOG_BUFFERThe default value of this parameter isMax (512KB, 128KB * CPU_COUNT). Generally, this default value is sufficient,WeYes, the Redo Log BufferWrite operations are quite frequentTherefore, too large Log Buffer settings are usually unnecessary. If the default value cannot meet the requirements, 3 MB is generally a reasonable adjustment start.

Whether to adjust the log_buffer parameter settings.DatabaseTo determine:

Sys @ ORCL>Select event #, name from v $ event_name where name = 'Log buffer space ';

EVENT # NAME

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109 log buffer space

When the Log Buffer Space waits for the event to appear and is more prominent, you can consider increasing the Log Buffer to reduce competition.

From Oracle10gAt the beginning, the allocation algorithm of LOG_BUFFER has changed becauseGranule, LThe allocation of OG_BUFFER must also be based on Granule,The Fixed SGA Size in the default SGA will share the Granule integer multiple with LOG_BUFFER.:

Sys @ ORCL>Select * from v $ version where rownum <2;

BANNER

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Oracle Database 10g Enterprise Edition Release 10.2.0.4.0-64bi

Sys @ ORCL>Show parameter log_buffer

NAME TYPE VALUE

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Log_buffer integer14238720

Sys @ ORCL>Select * from v $ sgainfo where name in ('fixed SGA size', 'redo Buffers', 'granule size ');

NAME BYTES RES

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Fixed SGA Size2091144No

Redo Buffers 14684160 No

Granule Size 16777216 No

Sys @ ORCL>Select (2091144 + 14238720)/16777216 from dual;

(2091144 + 14238720)/16777216

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. 973335743

If there is no obvious performance problem, the default setting is sufficient.