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Questions tagged [lmdb]

LMDB is an extraordinarily fast, memory-efficient database used by Monero. Its author Howard Chu is now a contributing member of the Monero development team.

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Why does monerod --detach return a differant block height than just running monerod?

I have monero installed on Raspbian on a Rpi3. I added monerod --detach & to the end of my /etc/rc.local. The result is that monerod --detach runs at boot, however it returns a differant block ...
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2answers
315 views

Unable to run multiple instances of monerod

Since version 0.10.2, Monero has reportedly supported the ability to run two or more instances of monerod with only one copy of the ful blockchain database: added support for multiple daemons using ...
3
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1answer
422 views

How to backup the blockchain file?

How can I periodically backup the blockchain file, without copying the entire file (just the new data that was added since the last backup)? I tried copying only the amount of bytes by which the ...
2
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1answer
301 views

Error Failed to commit a transaction to the db: operation not supported

Since the last fork, I have been unable to sync my monero nodes. I have tried from multiple machines and redownloaded the blockchain entirely, However, I still get the following results. Is anyone ...
3
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1answer
94 views

How to configure two daemons to use the same database?

Do I just have to make sure they have the same data-dir?
2
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0answers
186 views

monerod get stuck while loading blockchain from folder, but only offline!

I know that this should work, because I did this a while ago, but it doesn't. It opens as usual till "Loading blockchain from folder C:.....", But it works when I turn the internet back on. Is there ...
3
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1answer
597 views

How/when does the --db-salvage flag get used? What's it do?

This flag gets used when you suspect your copy of the blockchain may be corrupt, correct? What are the details? It's a daemon flag? Is it supposed to be used just until the blockchain is synced, ...
4
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1answer
275 views

Moving LMDB from Laptop to SBC?

I have a synced Database on my Laptop running W10, but I want run monerod on my Odroid C1 running debian linux. Is it possible to move the database from the Laptop to the SBC
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1answer
437 views

Is the Monero blockchain database portable between 32 and 64 bit architectures, and little/big endian architectures?

Monero uses LMDB for its database. Various data is saved in this database, including integers, such as the difficulty for a given block. LMDB is type agnostic, so does not any particular processing on ...
5
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1answer
319 views

Why would you need multiple daemons using one LMDB database?

From the release notes of the latest monero 0.10.2 version: added support for multiple daemons using the same LMDB database What sensible use case should that cover? From my understanding, LMDB ...
15
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1answer
769 views

Why does `monerod` on Raspberry Pi 3 with a copied LMDB not catch up with new blocks?

I have both a macOS system and a Raspberry Pi 3 on the same home network. Both are having Monero release 0.10.1.0 installed. I stopped the daemon on macOS, and then copied the entire .bitmonero ...
3
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1answer
2k views

Error when starting monerod: Failed to open db handle for m_blocks : MDB_CORRUPTED : Located page was wrong type

Every time I try to run monerod, I get the following error: Failed to open db handle for m_blocks : MDB_CORRUPTED : Located page was wrong type It briefly displays, and then shuts down the command ...
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2answers
2k views

Is the raw Monero blockchain file different for Linux, Windows, or Mac?

Is the raw Monero blockchain file different for Linux, Windows, or Mac? Where can I download it?
7
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1answer
1k views

Are the LMDB files cross-platform compatible?

I would like to know if the LMDB files are cross-platform compatible, more specifically between macOS and Linux. I am trying to import a raw blockchain (that I exported yesterday on macOS) onto a ...
5
votes
1answer
458 views

What does it mean when the Monero daemon says “LMDB Mapsize increased”?

I had an old daemon open and it was giving me the various SYNCHRONIZED OK messages that I was used to. Suddenly it said "LMDB Mapsize increased. Old: 13312MiB, New: 14336MiB". What does this mean?
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1answer
327 views

Is Monero the first cryptocurrency to use Confidential Transactions (RingCT), 0MQ, and LMDB?

I assume these technologies exist in other usages, but are we the first coin to implement them?
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2answers
678 views

How can one query the blockchain's database?

I realize that LMDB is very different from your typical SQL database, but is there a query language, or scripting language interface, that can be used to query the blockchain's database? I am aware ...
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1answer
2k views

What is the best way to pop the top block from the monero blockchain and fix a bad “unknown top block” error in the sync data process?

It appears whilst syncing the blockchain the computer halted resulting in a bad block at the top of the chain. After restarting no more blocks are being added and just repeated errors. There is ...
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1answer
484 views

Blockchain syncing and transactions verification

Recently I updated to version 0.10, but that wasn't an easy process. It took too long to go over my old blockchain and make it compatible with the new client, so I aborted that (iirc there was no ...
5
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2answers
277 views

bitmonerod data-dir in a virtualbox shared folder

I'm trying to run bitmonerod in a VirtualBox VM with --data-dir pointing to a directory in a shared folder from the host system. I get this error: If I do the same in the host system, using the ...
5
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1answer
454 views

blockchain_import fails, “Transaction has too many dirty pages - transaction too big”

I'm trying to set up a node and import the raw blockchain. OS is Whonix with 2GB RAM and plenty of free disk space hosted on Win7 ENT. user@host:~/Desktop/monero$ ./blockchain_import --input-file ...
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2answers
3k views

Why did Monero choose LMDB over alternative database types?

Did the Monero development find LMDB architect and developer Howard Chu because of its interest in LMDB? Or was LMDB introduced to the Monero development team because of Howard Chu's interest in ...
15
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3answers
5k views

How many transactions per second can the Monero network handle?

How many transactions per second can the Monero network (theoretically) handle? Did recent LMDB optimizations improve the speed that CPUs can confirm transactions? Is the current limiting factor CPU ...
5
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1answer
87 views

LMDB conversion vs downloading from scratch

What are the speed and security differences between a pre LMDB (0.8.6) to LMDB (0.9.4) conversion vs syncing the blockchain from scratch? I have a Linux Ubuntu desktop with 8GB RAM a 512 GM SSD and a ...
10
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3answers
342 views

Blockchain database file size variance by Operating System

I have a full node on both an Ubuntu 16.04 LTS and a Windows 10 device. Why is the database file containing blockchain a different size on each OS?