Oracle 视图 V$EQ_MESSAGE_CACHE_ADVICE 官方解释,作用,如何使用详细说明
本站中文解释
Oracle视图V$EQ_MESSAGE_CACHE_ADVICE提供了对Event Message Cache的详细情况分析,例如最大的CACHE_HITS,优先期最长的HIT_CNT,缓存命中率CACHE_HIT_RATE等。 该视图也可以显示当前时刻系统保持的活动消息和查询的消息。
使用方法:
1、查询Event Message Cache的分析监控信息:
SELECT message_type, sum(hits) cache_hits, max(hit_cnt) longest_hit_cnt, round(cpu_hits/hits,2) async_cpu_ratio, round((hits-cpu_hits)/hits*100,2) cache_hit_rate FROM v$eq_message_cache_advice GROUP BY message_type;
2、查询当前正在进行的消息:
SELECT message_type, message_text, holder_name, object_name, object_type, decode(status,’EXECUTING’,’USER_ACTIVE’,’QUEUED’) status FROM v$eq_message_cache_advice WHERE status IN (‘EXECUTING’,’QUEUED’);
官方英文解释
V$EQ_MESSAGE_CACHE_ADVICE
shows simulated metrics for a range of potential message cache sizes for Transactional Event Queues (TEQs). This view assists in cache sizing by providing information in the form of metrics as described below.
Column | Datatype | Description |
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Cache size for simulation (in megabytes) |
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Size factor with respect to the current cache size |
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Possible values:
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Estimated number of cached event stream partitions for this size |
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Estimated number of uncached event stream partitions for this size |
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Estimated number of event stream partitions evicted for this size |
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Estimated number of event stream partitions getting evicted per minute |
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Estimated number of event stream partitions unevicted by foreground processes |
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Estimated number of event stream partitions getting unevicted by foreground processes |
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Estimated number of event stream partitions unevicted by background processes |
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Estimated number of event stream partitions getting unevicted by background processes |
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Estimated number of background processes required for this size |
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Simulated number of messages being enqueued per second |
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Simulated number of messages being dequeued per second |
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Simulated average number of messages per cached event stream partitions |
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Simulated average memory per cached event stream partition (in megabytes) |
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Simulated average time to evict a cached event stream partition (in milliseconds) |
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Simulated average time to unevict a cached event stream partition (in milliseconds) |
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Reserved for internal use |
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Amount of time that was simulated for (in minutes) |
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The ID of the container to which the data pertains. Possible values include:
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Note:
This view is available starting with Oracle Database 21c.
See Also:
Oracle Database Advanced
Queuing User’s Guide for more information about Oracle Transactional Event Queues and Advanced Queuing