Hello, We're considering using ATS as a cache solution, but one of the features we must have -- regex purge -- seems to be too slow for our purposes.
We read on [1] that the cache's in-RAM index does not store the URL: "Data in HTTP headers cannot be examined without disk I/O. This includes the original URL for the object. The cache key is not stored explicitly and therefore cannot be reliably retrieved." So when ATS receives a regex purge request, it must scan the disk for each and every object in order to retrieve it's URL and compare it to the pattern being searched. Is this assumption correct? We're also assuming that this fact, that it must read from disc, is the reason why regex purge is slow. We briefly looked the source code, and it seems that ATS schedules a series of scans when it receives such a request, and these scans are scheduled in a conservative way, probably to not slow down the processing of other requests. We searched the bug reports to see if there were reports concerning this. We found issue TS-1323 [2] that seems to be about it, but we're not sure as the issue's text was brief (it does not mention regex purge, but does mention the fact that the object must be accessed). Are our assumptions correct? If so, is there a plan to change the way it's done (maybe have another index with the URLs, so the lookup would not have to read from disk?) [1] https://trafficserver.readthedocs.org/en/latest/arch/cache/cache-arch.en.html [2] https://issues.apache.org/jira/browse/TS-1323 Thanks in advance, -- Acácio Centeno Porto Alegre, Brasil + 55 51 3012 3005 Miami, USA + 1 305 704 8816 Quaisquer informações contidas neste e-mail e anexos podem ser confidenciais e privilegiadas, protegidas por sigilo legal. Qualquer forma de utilização deste documento depende de autorização do emissor, sujeito as penalidades cabíveis. Any information in this e-mail and attachments may be confidential and privileged, protected by legal confidentiality. The use of this document require authorization by the issuer, subject to penalties.
