Andres Freund f52c44ce48 ci: Improve ccache handling ... There previously were a number of issues: - We'd upload the cache even if we already had a high hit rate. That means we churn through the available cache space very quickly. For this we now check if the cache hit ratio is already high, and skip uploading a new cache in that case. - We'd generate per-branch caches, even if master's already would suffice, because the branch doesn't change much This is solved indirectly by the above. - The cache key allowed prefix matches based on the branch, e.g. master-pending would always use master's branch Replace the cache key element separator of - with :, which is not a valid part of a branch name. - When rebasing a feature branch, we'd start with just that branch's cache, rather than also having the newer cache of master available This is solved by downloading by master's and the feature branch's cache, simply overlaying both. That's possible because ccache is content addressed. - The size of a cache would increase to the max, even though there likely will be no benefit from old cache entries. Address this by explicitly evicting old data and also recompressing the cache before uploading it. In my testing this utilizes the available cache space (10GB for personal accounts) much more effectively than before. The not entirely trivial determination of whether it's worth uploading a cache entry is moved to a python script. I first had it as shell, but that gets awkward. This way it'd also be more viable to use ccache for msvc at some point. The per-job redundancies are a bit annoying. There's a way around that, by using composite actions, but I think that might be harder to understand, without all that much of an improvement. Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com> Discussion: https://postgr.es/m/7eugqon2ilnaq6yimtq7prtl5wlia43mhpmwlydzlw4u4wonaz@hh2fagz5bjuu		2026-06-08 15:26:47 -04:00
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pg-ci.yml	ci: Improve ccache handling	2026-06-08 15:26:47 -04:00