Fix bugs related to best-effort queries #3125
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…id returning uncommitted data.
martinmr
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Mar 12, 2019
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Just a question about the choice of int over bool but otherwise LGTM.
Reviewed 8 of 8 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @manishrjain)
protos/pb.proto, line 72 at r1 (raw file):
uint64 read_ts = 13; int32 cache = 14;
Why not a bool instead of an int. There's only two choices so far. Do you anticipate more choices in the future?
… to the system without doing any transactions. This causes the group checksum to mismatch and stay that way. The fix would push something to Oracle update channel so a new OracleDelta would be produced and sent out.
manishrjain
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manishrjain
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Mar 13, 2019
- Don't use a pending txn cache when running best effort queries to avoid returning uncommitted data. If it gets used, a best-effort query ends up reading uncommitted data from another txn's cache who owns the start ts that best-effort query is "borrowing." - If no txns are going on in the system and we create new predicates by asking for them (case in v1.0 series), a best-effort query would block forever due to predicate checksum mismatch between `OracleDelta` and `MembershipState`. Fix that by sending out an empty `OracleDelta` from Zero after a tablet update. - Add tests in counter tool to check for these edge cases. Changes: * Don't use a pending txn cache when running best effort queries to avoid returning uncommitted data. * Fix a bug caused by best effort queries, where we add a new predicate to the system without doing any transactions. This causes the group checksum to mismatch and stay that way. The fix would push something to Oracle update channel so a new OracleDelta would be produced and sent out. * Add tests to ensure that best effort queries work as expected.
dna2github
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Jul 19, 2019
- Don't use a pending txn cache when running best effort queries to avoid returning uncommitted data. If it gets used, a best-effort query ends up reading uncommitted data from another txn's cache who owns the start ts that best-effort query is "borrowing." - If no txns are going on in the system and we create new predicates by asking for them (case in v1.0 series), a best-effort query would block forever due to predicate checksum mismatch between `OracleDelta` and `MembershipState`. Fix that by sending out an empty `OracleDelta` from Zero after a tablet update. - Add tests in counter tool to check for these edge cases. Changes: * Don't use a pending txn cache when running best effort queries to avoid returning uncommitted data. * Fix a bug caused by best effort queries, where we add a new predicate to the system without doing any transactions. This causes the group checksum to mismatch and stay that way. The fix would push something to Oracle update channel so a new OracleDelta would be produced and sent out. * Add tests to ensure that best effort queries work as expected.
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Don't use a pending txn cache when running best effort queries to avoid returning uncommitted data. If it gets used, a best-effort query ends up reading uncommitted data from another txn's cache who owns the start ts that best-effort query is "borrowing."
If no txns are going on in the system and we create new predicates by asking for them (case in v1.0 series), a best-effort query would block forever due to predicate checksum mismatch between
OracleDeltaandMembershipState. Fix that by sending out an emptyOracleDeltafrom Zero after a tablet update.Add tests in counter tool to check for these edge cases.
This change is