Apache Impala
bitcoinbook
Apache Impala | bitcoinbook | |
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1 | 347 | |
1,079 | 22,569 | |
1.2% | 0.6% | |
9.7 | 9.9 | |
8 days ago | about 2 months ago | |
C++ | HTML | |
Apache License 2.0 | GNU General Public License v3.0 or later |
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Apache Impala
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Word-Aligned Bloom Filters
> whether this would really work out in most workloads
> just because it keeps the cache-lines hotter and less likely to be evicted.
Okay, so keeping cache for a bloom filter problem is real - but the real force evicting memory out of the cache line is the next row-group you read + all the other stuff you have to do when you implement this in a database product.
So the two things I work with, Apache Hive and Apache Impala switched to a blocked bloom filter at different points in time.
Hive BloomKFilter - https://github.com/apache/hive/blob/master/storage-api/src/j...
Impala/Kudu one - https://github.com/apache/impala/blob/master/be/src/kudu/uti...
The C++ one also has an AVX specialization, while the Java one relies on the JVM to do it (not always) - https://github.com/apache/impala/blob/master/be/src/kudu/uti...
We ran a lot of trivial benchmarks and several benchmarks where the shuffle-join (not sort-merge, this is just a partitioned hash join) generates a bloom filter (a semijoin) before sending rows out and the 1-cache line version won out when the bloom filter went slightly over the 1 Million + 5% rate [1].
The regular bloom filter went from (38ns -> 108ns for 1k -> 1m items), while the BloomK stuck at (27ns) despite making room for a million times more items in the bloom. The bloom-1 (which is the 64bit version) underperformed on accuracy (was ~2x faster at 16ns per op, but worse at filtering out items).
[1] - https://github.com/prasanthj/bloomfilter/tree/master/benchma...
bitcoinbook
- Best Website for a noob to "learn bitcoin"?
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Free ebooks on Cryptocurrency, a small collection I read
"Mastering Bitcoin" by Andreas M. Antonopoulos: The printed version is not free, the complete text is available on GitHub. It's an excellent resource for understanding Bitcoin from a technical perspective.
- Writing a summary on HD wallets, first part done, correct so far ?
- Anything missing?
- Any good book about the math behind the encryption within Bitcoin?
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How do I find the target hash
The target is stored in the block header. You can see it in any block explorer labeled BITS or nBits. It is stored in a compressed format, as described in Mastering Bitcoin https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch10.asciidoc Scroll down to "Target Representation"
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Free courses to learn about bitcoin and cryptocurrencies?
Mastering Bitcoin is a free book - https://github.com/bitcoinbook/bitcoinbook
- Wie funktionieren Finanzen?
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Seeking Guidance: Best Path to Mastering Blockchain and Affordable Master Programs
I also highly recommend that you Read this book "Mastering bitcoin", its free and open source: https://github.com/bitcoinbook/bitcoinbook
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Introducing Ledger Recover & Answering Your Questions
You should read this chapter - it kinda explains why the chip need to be able to manipulate and access the private key. It works exactly the same way for every hardware wallet.