bitcoind – does Bitcoin Core automatically use reindex when you specify txindex=1 with existing sync’d chain?

I sync’d a bitcoin node with Bitcoin Core Qt GUI. Hundreds of GB, naturally.

I realized I needed txindex on for Lightning node stuff, so I changed the conf file via the GUI to include txindex=1. I launched it on my Mac and then slapped myself in the face – how would I tell it to reindex instead of throwing away my database?? Didn’t wanna download all those GB again.

But then I noticed debug.log started saying this:

2020-11-30T06:07:43Z Syncing txindex with block chain from height 498564
2020-11-30T06:08:28Z Syncing txindex with block chain from height 500148

which, if I remember right means it’s doing a reindex, not a full-blown restart of a sync. Checked on disk, and indeed, files still there.

I’m grateful, but also mystified. Questions:

  1. does Bitcoin Core see when you’re about to throw away a full sync with txindex=1 and then inject a -reindex into the start command?
  2. how can I see the startup command that bitcoin-qt uses when I start with with the Mac OSX launcher?

legal – Bitcoin Core Desktop Wallet retaining my coins due to Gap Limit being exceeded

trying to send coins am unable to enter address. have to load from clipboard, cannot copy and paste, address bar goes red, disables send functions. i explore reasons, seems 20 unused address gap limit is probably the reason. researched solutions. only feasible solution seems is sending funds to unused addresses, did so with 11 addresses to no effect – i am still almost 80 over. looks like i exceeded 20 over a year ago. money sat in desktop wallet unusable for a week now. Block chain is up to date. cannot see any solutions here or anywhere else. 1. can anyone offer a solution? i am on Ubuntu – maybe there is a terminal gap limit extension solution i am unaware of? 2. how is this possible that an automated system can withhold my own money from me over a technicality which isn’t ever flagged to users? is this even legal? will it ever release my funds if i can’t sort this problem out and do i have redress if not? seems a ludicrous situation and design flaw. any suggestions or help would be appreciated, thanks.

bitcoin core – How Nodes suggests for what the next block in the chain should be by solving cryptographic hash by random guesses

Well, According to my research, Any node can collect a set up unconfirmed transactions into a block and broadcast to the rest of the network as a suggestion for what the next block in the chain should be, by solving the cryptographic hash by random guesses. Moreover, the hash function creates something like a 32byte number might be using SHA256. So, I want to know who creates random numbers? and how nodes do guessing?

Please let me know if my concept is wrong. I will appreciate your guidance. Thanks

Accidentally Sent BTC to bitcoin core watch-only wallet with private keys disabled

I think I already know the answer to this, but I just want to make sure as it will result in a loss of funds. I have Specter desktop connected to my bitcoin-core. But because I also sometimes use the core wallet as a hot wallet as well, I accidentally generated the address in the core wallet that is linked to my specter wallet, but the core wallet is a watch-only wallet with the priv keys disabled and then I sent funds to this address and not the address generated by specter or my default core hot wallet. But because this is watch-only my core wallet does not have the priv keys. I am doubtful but is their anyway for the wallet to know it generated this key by enabling priv key.

bitcoind – Bitcoin Core 0.13 How many addresses it can **effectively** manage?

Try it yourself. In Tools, Debug Console, try getnewaddress. Create as many as you want. See if your wallet performance changes. wallet.dat size will grow, but I can’t 4MB vs 32MB has made much of a difference.

DASH wallet when it generates 1,000 addresses at a time for its PrivateSend feature, I can’t notice any difference in performance.

“Effectively” manage is really seeking an opinion where the system components the node is running on will tell you what it can handle “effectively”.

Are there any other ways of speeding up the building of Bitcoin Core PRs other than ccache?

I am already using ccache to speed up recompilation when building Bitcoin Core PRs. Are there any other ways of speeding up the process?

bitcoin core – SHA256 speedup possible if executed on GPU

Is it possible to speed up hashing if hashing is done on a GPU? Does that even make sense or are the CPU instructions faster because for normal signature verification you don’t gain by parallelizing the execution? What about latency between GPU and CPU?

Clarification: I am not talking about mining. I only want to know if the node would be faster (for example during IBD) if hashing was done on the GPU.

c# – Should I use “–self-contained true” when publishing a .NET Core 3.1 Lambda to AWS?

Simple question as the title implies… I know with a .NET 5.0 package, I would have to provide it as a custom runtime and package it as self contained. But with .NET Core 3.1 which is natively supported by AWS, are there any pros/cons to using the flag “–self-contained true”?

architecture – Which web development stack should I use if core script is written in Python?

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composer – How can I update core to 8.9.10?

I’m trying to apply the security update for core by updating it to 8.9.10 with the following command:

composer update drupal/core

But this only brings back the following notice:

Nothing to install or update

What am I doing wrong? How can I update core to 8.9.10?