Stress test is underway - Watch your fees.

[p3yot33at3r]

can someone explain to me why some blocks have small size despite of the huge number of transactions waiting in the mempool?

A miner can decide for himself how many transactions he wishes to include in a block, if any.
It's perfectly "legal" to "make small blocks" even when there are thousands of transactions waiting.

Why do they sometimes not include transactions?
Is it a bug or are they just doing it to be mean?

It's a combination of greed & being mean. Some of the largest pools (f2pool, antpool, etc) only churn out empty blocks, & by doing so they are not contributing to the network at all. See this thread:

https://bitcointalk.org/index.php?topic=1085800.0

[ranochigo]

can someone explain to me why some blocks have small size despite of the huge number of transactions waiting in the mempool?

A miner can decide for himself how many transactions he wishes to include in a block, if any.
It's perfectly "legal" to "make small blocks" even when there are thousands of transactions waiting.

Why do they sometimes not include transactions?
Is it a bug or are they just doing it to be mean?

By not including transaction, the size would be smaller hence the time taken to propagate is faster, reducing orphans. This in turn reduces their profit from transaction. I have observed that if two blocks are mined with little time gap between them, it would have a good chance for the younger transaction to have a small block size.

[RoadTrain]

can someone explain to me why some blocks have small size despite of the huge number of transactions waiting in the mempool?

A miner can decide for himself how many transactions he wishes to include in a block, if any.
It's perfectly "legal" to "make small blocks" even when there are thousands of transactions waiting.

Why do they sometimes not include transactions?
Is it a bug or are they just doing it to be mean?

Usually that's because the pool didn't have time to include transactions in a block (send new work to miners), when a new block is found shortly after the previous one. In this case, miners mine an empty block, until the pool sends them updated work (usually within a minute).

[--Encrypted--]

A miner can decide for himself how many transactions he wishes to include in a block, if any.
It's perfectly "legal" to "make small blocks" even when there are thousands of transactions waiting.

It's a combination of greed & being mean. Some of the largest pools (f2pool, antpool, etc) only churn out empty blocks, & by doing so they are not contributing to the network at all. See this thread:

https://bitcointalk.org/index.php?topic=1085800.0

thanks, both of you. and that thread clears up a lot of things regarding the small blocks.

[teukon]

can someone explain to me why some blocks have small size despite of the huge number of transactions waiting in the mempool?

Block generators are free to choose which transactions to include in their blocks.  Among other things, their motivations to include a given transaction are influenced by:

• Its fee.
• Its orphan cost (related to its size as data).
• The effect on Bitcoin's reputation.
• For mining pools, their reputation among potential users.

Today, the block subsidy is so high and fees are so low that some block generators consider it profitable to produce empty blocks, minimising the possibility that their block will be orphaned and avoiding the cost of running a full node.  Assuming appropriate difficulty adjustments, this increases the average time to first confirmation for all Bitcoin users.

[Lituation]

Yesterday I sent some coins with normal fee, they are still unconfirmed. I don't know why miners don't accept yet.
I used normal recommended fee in Bitcoin Core which is 6k sat per kb.

6k satoshi per kb seems a bit low imo, most of the transactions getting confirmed are around 0.0002btc in fees and around 600-700kb in size.

0.00006000 per kb = 0.03600000 for 600kb

so 6ksat per kb is actually quite high!!

Yes, it's very high comparing to other transactions. Surprisingly one of my transactions still unconfirmed with that fee. 2 of others got confirmed after ~48 hours.