Automatic caching of parsed STRING config values #12735
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bneradt
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Dec 5, 2025
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| auto &parsed = ParsedConfigCache::lookup(conf, std::string_view(value, length)); | ||
| s->t_state.my_txn_conf().negative_caching_list = parsed.status_code_list; |
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These ParsedConfigCache::lookup are the high level view of where the value of this patch happens. Instead of calling the conversion logic for each of these "complex" strings (like the negative caching status list, in this example) every transaction, this parsed value retrieval is called through an interface that caches the results so that the compution is only done once.
This introduces ParsedConfigCache in HttpConfig to automatically cache parsed results for STRING configs that require expensive parsing. When TSHttpTxnConfigStringSet() is called for configs like negative_caching_list, insert_forwarded, server_session_sharing.match, negative_revalidating_list, or host_res_data (ip_resolve), the parsing now happens once per unique value and is cached for subsequent calls. This optimization is transparent to plugins - they call TSHttpTxnConfigStringSet() as usual and automatically benefit from the caching. Fixes: apache#12292
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This introduces ParsedConfigCache in HttpConfig to automatically cache parsed results for STRING configs that require expensive parsing. When TSHttpTxnConfigStringSet() is called for configs like negative_caching_list, insert_forwarded, server_session_sharing.match, negative_revalidating_list, or host_res_data (ip_resolve), the parsing now happens once per unique value and is cached for subsequent calls. This optimization is transparent to plugins - they call TSHttpTxnConfigStringSet() as usual and automatically benefit from the caching.
Fixes: #12292