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refactor: [Memory optimization] Block index duplicate PoS state #1945

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cyrossignol
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@cyrossignol cyrossignol commented Oct 27, 2020

This is part of a series of changes that optimize the memory usage of Gridcoin's block index. According to Valgrind's heap profiler (Massif), these changes will decrease memory usage of the application by over 500 MB after the final PR merges. Because these optimizations apply to every block, memory savings will continue to accrue as the chain grows. I'm breaking-up the commits into separate PRs because the branch has become too unwieldy to review in one submission.


This refactors the duplicate stake spam mitigation to remove the following fields from the block index:

  • prevoutStake
  • nStakeTime

...for a memory reduction of 40 bytes per block.

It also replaces the setStakeSeen container with a hash table of transient staking proof hashes. The setStakeSeen container holds a copy of the block index fields described above.

This saves an additional 40 bytes of memory for every block plus the administrative overhead needed to store each record in a std::set container (±28 bytes depending on the platform and library implementation).

I also optimized storage for the original setStakeSeenOrphan set by consolidating outpoints seen more than once in orphan blocks. This doesn't have much of an effect under normal circumstances.

This adds a function that applies the proof-of-stake timestamp mask to a
block or transaction timestamp to centralize and formalize the operation
into an API for other areas.
This refactors the duplicate stake spam mitigation to remove the
following fields from the block index:

  - prevoutStake
  - nStakeTime

...for a memory reduction of 40 bytes per block.

It also replaces the setStakeSeen container with a hash table of
transient staking proof hashes. The setStakeSeen container holds
a copy of the block index fields described above.

This saves an additional 40 bytes of memory for every block plus
the administrative overhead of storing each record in a std::set
container (28 bytes?).

I also optimized storage for the original setStakeSeenOrphan set
by consolidating outpoints seen more than once in orphan blocks.
This doesn't have much of an effect under normal circumstances.
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utACK

src/gridcoin/staking/kernel.cpp Show resolved Hide resolved
src/gridcoin/staking/spam.h Show resolved Hide resolved
@jamescowens jamescowens merged commit a06debf into gridcoin-community:development Nov 2, 2020
@cyrossignol cyrossignol changed the title refactor: [Memory optimization] Remove duplicate PoS state from the block index refactor: [Memory optimization] Block index duplicate PoS state Nov 2, 2020
jamescowens added a commit that referenced this pull request Mar 1, 2021
 Added
 - gui: Add RAC column to wizard summary page projects table #1951 (@cyrossignol)
 - rpc: clean up the superblocks function and add magnitude to getmininginfo #1966 (@jamescowens)
 - rpc: Add transaction size to RPC output #1971 (@cyrossignol)
 - voting: Add user-facing support for poll response types #1976 (@cyrossignol)
 - gui: Port Bitcoin Intro class (implement the ability to choose a data directory via the GUI) #1978 (@jamescowens)
 - gui: Port Bitcoin MacOS app nap manager #1991 (@jamescowens)
 - mining, rpc: Implement staking efficiency measure and improve SelectCoinsForStaking and CreateCoinStake #1992 (@jamescowens)
 - accrual, rpc: Implement auditsnapshotaccruals #2001 (@jamescowens)
 - docs: add doxygen support #2000 (@div72)
 - beacon: Specialized beacon storage in leveldb #2009 (@jamescowens)
 - rpc: Add a call to dump contracts in binary form #2011 (@div72)
 - rpc: Add boolean option to report active beacons only in beaconreport #2013 (@jamescowens)
 - consensus: Set Hilda mainnet hardfork height to 2197000 #2022 (@jamescowens)

 Changed
 - refactor: [Memory optimization] Block index duplicate PoS state #1945 (@cyrossignol)
 - refactor: [Memory optimization] Block index superblock and contract flags #1950 (@cyrossignol)
 - refactor: [Memory optimization] Remove stake modifier checksums #1954 (@cyrossignol)
 - refactor: [Memory optimization] Block index allocation overhead #1957 (@cyrossignol)
 - refactor: [Memory optimization] Remove block index subsidy fields #1960 (@cyrossignol)
 - refactor: [Memory optimization] Separate chain trust from the block index #1961 (@cyrossignol)
 - refactor: [Memory optimization] Eliminate padding between block index fields #1962 (@cyrossignol)
 - beacon, gui: Add check for presence of beacon private key to updateBeacon() #1968 (@jamescowens)
 - util: Enhance ETTS calculation #1973 (@jamescowens)
 - refactor: Use new clamp in util.h #1975 (@jamescowens)
 - gui: Redo global status for overview #1983 (@jamescowens)
 - util: Improvements to MilliTimer class and use in the miner and init #1987 (@jamescowens)
 - rpc: Move rpc files to directory #1995 (@Pythonix)
 - rpc: Enhance consolidateunspent and fix fee calculation #1994 (@jamescowens)
 - contract: Double the lookback scope of contract replay #1998 (@jamescowens)
 - net: Don't rely on external IP resolvers #2002 (@Tetrix42)
 - beacon: Change beacon map to pointers #2008 (@jamescowens)
 - gui: Update bitcoin_sv.ts #2014 (@sweede-se)
 - util: Update snapshot URLs and add accrual directory #2019 (@jamescowens)
 - beacon: Tweak BeaconRegistry::Revert #2020 (@jamescowens)
 - rpc, qt: bump fees @2023 (@div72)

 Removed
 - researcher: Remove automatic legacy beacon key import #1963 (@cyrossignol)
 - util: Revert "Close LevelDB after loading the block index" #1969 (@cyrossignol)
 - ci: Fix python symlink issue & remove travis #1990 (@div72)
 - ci: remove python workaround #2005 (@div72)

 Fixed
 - gui: fix mandatory/leisure detection of upgrade check #1959 (@Pythonix)
 - voting: Fix title in "gettransaction" RPC for legacy poll contracts @1970 (@cyrossignol)
 - gui: Fix missing menu items on macOS #1972 (@scribblemaniac)
 - rpc: Fix answer offset in "votedetails" #1974 (@cyrossignol)
 - voting: Implement missing try-catch in VotingVoteDialog::vote #1980 (@jamescowens)
 - scraper: Add check for minimum housekeeping complete in scraper #1977 (@jamescowens)
 - voting: Fix nonsense vote weights for legacy polls #1988 (@cyrossignol)
 - voting: Fix incorrect field returned in ResolveMoneySupplyForPoll() #1989 (@cyrossignol)
 - consensus, accrual: Fix newbie accrual #2004 (@jamescowens)
 - log: grammar correction #2016 (@nathanielcwm)
 - wallet: Correct nMinFee fee calculation in CreateTransaction #2021 (@jamescowens)
 - rpc, miner: Correct GetLastStake #2026 (@jamescowens)
 - wallet: Fix bug in CreateTransaction causing insufficient fees #2029 (@jamescowens)
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