Move hash->CBlockIndex BDB into its own database, blkhash.dat #1282

pull jgarzik wants to merge 7 commits into bitcoin:master from jgarzik:blockindex changing 8 files +287 −213

jgarzik commented at 7:15 AM on May 13, 2012: contributor
blkindex.dat stores all kinds of data, and as such, each key is overloaded to form a namespace. All keys beginning with "blockindex" form the hash->CBlockIndex data that is loaded into mapBlockIndex.

This change moves mapBlockIndex data to its own database, custom tailored for the sort of data we wish to store:
- BDB type changed from btree to hash
- key is uint256 hash, with no prefixes
Usage is cleaner, and uses slightly less CPU and disk space than the previous solution.

COMPATIBILITY STATUS: A new block chain must be downloaded, or at least reindexed. As such, may want to delay this change, if other major database changes are planned.

MERGE STATUS: Ready for review and comment, but not ready for immediate upstreaming.
laanwj commented at 7:47 AM on May 13, 2012: member

Good idea. It's bad form to put different stuffs into one database table.
sipa commented at 9:33 AM on May 13, 2012: member

Not sure whether an entirely separate file is better, or just a separate database within the same file (which bdb also supports). You'd need to implement cross-db transaction in the glue layer anyway before this is safe.
Always check return values of TxnBegin() and TxnCommit() 0fb78eae34
jgarzik commented at 5:23 AM on May 14, 2012: contributor

Rebased on top of #1293 (BDB environment encapsulation)
jgarzik commented at 5:54 AM on May 14, 2012: contributor

Updated to do cross-db transactions.
Diapolo commented at 6:03 AM on May 14, 2012: none

This includes #1293 now?
jgarzik commented at 6:25 AM on May 14, 2012: contributor

Yes, see comment above.

Reorganize(): remove spurious TxnAbort()

If Reorganize() fails, then its caller, CBlock::SetBestChain(),
will call TxnAbort().

Redundant TxnAbort() calls are harmless.  The second will return an
error return value, with no other side effects.  TxnAbort() return
values are generally never checked.  The impact is nil.

060921932f

Merge branch 'extra-abort' into dbenv e19963d5ba

Encapsulate BDB environment inside new CDBEnv class

Cleans up and organizes several scattered functions and variables related to
the BDB env.  Class CDBInit() existed to provide a
guaranteed-via-C++-destructor cleanup of the db environment.

A formal CDBEnv class provides all of this inside a single wrapper.

1e3624093d

Create CDBEnv::TxnBegin(), and use it in CDB::TxnBegin() accb0268e2
Remove unused nested BDB transaction support c7ab7e596e

Move hash->CBlockIndex BDB into its own database, blkhash.dat

blkindex.dat stores all kinds of data, and as such, each key is overloaded to
form a namespace.  All keys beginning with "blockindex" form the
hash->CBlockIndex data that is loaded into mapBlockIndex.

This change moves mapBlockIndex data to its own database, custom tailored for
the sort of data we wish to store:

- BDB type changed from btree to hash
- key is uint256 hash, with no prefixes

Usage is cleaner, and uses slightly less CPU and disk space than the previous
solution.

ccb0a0d128

jgarzik commented at 4:56 PM on May 14, 2012: contributor

DEPENDENCY UPDATE: #1295, #1300, and #1293, in that order
jgarzik commented at 6:10 PM on May 14, 2012: contributor

Closing -- about to reopen a similar but revised pull req.
jgarzik closed this on May 14, 2012
lateminer referenced this in commit 1e4f5a64e9 on Jan 22, 2019
lateminer referenced this in commit 76f29fccf3 on May 6, 2020
DrahtBot locked this on Sep 8, 2021

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#1303 Split BDB database blkindex.dat into multiple databases