← Back to team overview

maria-developers team mailing list archive

Re: [Commits] Rev 3138: Early check of subquery cache hit rate added to limit its performance impact in the worst case. in file:///home/bell/maria/bzr/work-maria-5.3-scache_impact/



01.08.2011 10:12, Timour Katchaounov пишет:

Could you explain why these new constants are defines,
and not declared const variables:

=== modified file 'sql/sql_expression_cache.cc'
--- a/sql/sql_expression_cache.cc    2011-07-28 14:10:29 +0000
+++ b/sql/sql_expression_cache.cc    2011-08-01 06:34:55 +0000
@@ -26,6 +26,11 @@
   hit_rate = hit / (miss + hit);
+  Number of cache miss to check hit ratio (maximum cache performance
+  impact in the case when the cache is not applicable)

All of these are potentially possible to tune, why make them
compile-time defines?

Heh, that is what I wanted to discuss. On one hand too many parameters is bad on other hand too simple is not good also...