Query: Skip formatting strings if debug logging is disabled #7678
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Signed-off-by: Walther Lee <[email protected]>
yeya24
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Aug 30, 2024
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Thanks. This LGTM. Thanks for fixing the issue
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Do we actually need those debugging messages at all? |
saswatamcode
previously approved these changes
Sep 2, 2024
yeya24
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Oct 1, 2024
Signed-off-by: Walther Lee <[email protected]>
jnyi
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Oct 17, 2024
…o#7678) * skip formatting debug str if debug logging is disabled Signed-off-by: Walther Lee <[email protected]> * make statis strings const Signed-off-by: Walther Lee <[email protected]> --------- Signed-off-by: Walther Lee <[email protected]>
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After upgrading from v0.34.1 to v0.36.0, I see some queriers using about 10 times more CPU than before. These queriers only receive ~16 instant http q/s and have over 20 endpoints.
A pprof profile showed that the GC is using most of the CPU, so I ran a pprof heap alloc_space, and the problem seems to be
fmt.Sprintfused in the debug message in the store proxy, even if debug logging is disabled.Changes
I added a validation to skip the string formatting if debug logging is disabled.
Verification
I deployed a patch with this change and it definitely fixed the CPU usage. This graph is avg CPU usage after removing the formatting in
matchingStoresand then after removing it instoreMatchesandstoreMatchDebugMetadata.