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Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
Two keys might map into the same bucket\n
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An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
An empty Bloom Filter is an array of m bits, all set to 0. There must be K hash functions defined, each of which maps some element to one of the m array positions with an uniform random distribution.\nTo add an element, feed it to each of the k hash functions to get k array positions, and set the bits to 1.\nTo test for an element, feed it to each of the k hash functions to get k array positions: if any of the bits at these positions are 0, the element is not in the set.\nUnion and intersection of Bloom filters: A simple bitwise OR and AND operations\n
Tiger is a cryptographic hash function optimised for 64-bit platform (1995)\nSize: 192 bits (truncated versions: 128 and 160 bits).\nMurmur hash is very very fast and low collision rate (2008).\nAnother good non-cryptographic hash function is the Jenkins Hash Function (Bob Jenkins, 1997)\nHashing with checksum functions is possible, and may produce a sufficiently uniform distribution of hash values, as long as the hash range size n is small compared to the range of the checksum or fingerprint function. The CRC32 checksum provides only 16 bits (the higher half of the result) that are usable for hashing.\n\n\n
Popular in distributed web caches (small cost, big potential gain).\nThe Google Chrome web browser uses Bloom filters to speed up its Safe Browsing service.[6]\nIn Relational Databases, Bloom Filters are often used for JOINs\n
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All the bits for an element not yet inserted might already be set.\nThere is a clear tradeoff between m and the probability of a false positive.\nThe value of k that minimizes the probability of false positives is 0.7m/n\n
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An optimal number of hash functions k has been assumed\n
Standard bloom filters can’t handle deletions: if deleting x means resetting 1s to 0s, then deleting an entry might delete several others.\n\n
2006. Precisely eliminating duplicates in an unbounded data stream (i.e. when you don’t kow the size of the data set up front) is not feasible in many streaming scenarios. A common characteristic of these algorithms is the underlying assumption that the whole data set is stored and can be accessed if needed.\nUse cases: URL crawlers, Network monitoring (number of accesses by IP in the past hour), trending topics.\nIn many data stream applications, the allocated space is rather small compared to the size of the stream. When more and more elements arrive, the fraction of zeros\nin the Bloom Filter will decrease continuously, and the false positive rate will increase accordingly, finally reaching the limit, 1, where every distinct element will be reported as a\nduplicate, indicating that the Bloom Filter is useless.\nFor the regular Bloom Filter, there is no way to distinguish the recent elements from the past ones\n\ngithub?\n
2006. Precisely eliminating duplicates in an unbounded data stream (i.e. when you don’t kow the size of the data set up front) is not feasible in many streaming scenarios. A common characteristic of these algorithms is the underlying assumption that the whole data set is stored and can be accessed if needed.\nUse cases: URL crawlers, Network monitoring (number of accesses by IP in the past hour), trending topics.\nIn many data stream applications, the allocated space is rather small compared to the size of the stream. When more and more elements arrive, the fraction of zeros\nin the Bloom Filter will decrease continuously, and the false positive rate will increase accordingly, finally reaching the limit, 1, where every distinct element will be reported as a\nduplicate, indicating that the Bloom Filter is useless.\nFor the regular Bloom Filter, there is no way to distinguish the recent elements from the past ones\n\ngithub?\n
2006. Precisely eliminating duplicates in an unbounded data stream (i.e. when you don’t kow the size of the data set up front) is not feasible in many streaming scenarios. A common characteristic of these algorithms is the underlying assumption that the whole data set is stored and can be accessed if needed.\nUse cases: URL crawlers, Network monitoring (number of accesses by IP in the past hour), trending topics.\nIn many data stream applications, the allocated space is rather small compared to the size of the stream. When more and more elements arrive, the fraction of zeros\nin the Bloom Filter will decrease continuously, and the false positive rate will increase accordingly, finally reaching the limit, 1, where every distinct element will be reported as a\nduplicate, indicating that the Bloom Filter is useless.\nFor the regular Bloom Filter, there is no way to distinguish the recent elements from the past ones\n\ngithub?\n
2006. Precisely eliminating duplicates in an unbounded data stream (i.e. when you don’t kow the size of the data set up front) is not feasible in many streaming scenarios. A common characteristic of these algorithms is the underlying assumption that the whole data set is stored and can be accessed if needed.\nUse cases: URL crawlers, Network monitoring (number of accesses by IP in the past hour), trending topics.\nIn many data stream applications, the allocated space is rather small compared to the size of the stream. When more and more elements arrive, the fraction of zeros\nin the Bloom Filter will decrease continuously, and the false positive rate will increase accordingly, finally reaching the limit, 1, where every distinct element will be reported as a\nduplicate, indicating that the Bloom Filter is useless.\nFor the regular Bloom Filter, there is no way to distinguish the recent elements from the past ones\n\ngithub?\n
RBF: permit the removal of selected false positives at the expense of generating random false negatives.\n
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They are used to protect any kind of data stored, handled and transferred in and between computers\n
Each inner node is the hash value of the concatenation of its two children.\nThe principal advantage of Merkle tree is that each branch of the tree can be checked independently without requiring nodes to download the entire tree or the entire data set.\n\n\n
For each key range of data, each member in the replica group compute a Merkel tree (a hash encoding tree where the difference can be located quickly) and send it to other neighbors. By comparing the received Merkel tree with its own tree, each member can quickly determine which data portion is out of sync. If so, it will send the diff to the left-behind members.\n\nTiger is a cryptographic hash function optimised for 64-bit platform (1995)\nSize: 192 bits (truncated versions: 128 and 160 bits)\n
For each key range of data, each member in the replica group compute a Merkel tree (a hash encoding tree where the difference can be located quickly) and send it to other neighbors. By comparing the received Merkel tree with its own tree, each member can quickly determine which data portion is out of sync. If so, it will send the diff to the left-behind members.\n\nTiger is a cryptographic hash function optimised for 64-bit platform (1995)\nSize: 192 bits (truncated versions: 128 and 160 bits)\n
For each key range of data, each member in the replica group compute a Merkel tree (a hash encoding tree where the difference can be located quickly) and send it to other neighbors. By comparing the received Merkel tree with its own tree, each member can quickly determine which data portion is out of sync. If so, it will send the diff to the left-behind members.\n\nTiger is a cryptographic hash function optimised for 64-bit platform (1995)\nSize: 192 bits (truncated versions: 128 and 160 bits)\n
For each key range of data, each member in the replica group compute a Merkel tree (a hash encoding tree where the difference can be located quickly) and send it to other neighbors. By comparing the received Merkel tree with its own tree, each member can quickly determine which data portion is out of sync. If so, it will send the diff to the left-behind members.\n\nTiger is a cryptographic hash function optimised for 64-bit platform (1995)\nSize: 192 bits (truncated versions: 128 and 160 bits)\n
Hash trees can be used to protect any kind of data stored, handled and transferred in and between computers.\nBefore downloading a file on a p2p network, the top hash is acquired from a trusted source. When the top hash (root hash) is available, the hash tree can be received form any non-trusted source.\nCurrently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks\n
Hash trees can be used to protect any kind of data stored, handled and transferred in and between computers.\nBefore downloading a file on a p2p network, the top hash is acquired from a trusted source. When the top hash (root hash) is available, the hash tree can be received form any non-trusted source.\nCurrently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks\n
Hash trees can be used to protect any kind of data stored, handled and transferred in and between computers.\nBefore downloading a file on a p2p network, the top hash is acquired from a trusted source. When the top hash (root hash) is available, the hash tree can be received form any non-trusted source.\nCurrently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks\n
Hash trees can be used to protect any kind of data stored, handled and transferred in and between computers.\nBefore downloading a file on a p2p network, the top hash is acquired from a trusted source. When the top hash (root hash) is available, the hash tree can be received form any non-trusted source.\nCurrently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks\n
Hash trees can be used to protect any kind of data stored, handled and transferred in and between computers.\nBefore downloading a file on a p2p network, the top hash is acquired from a trusted source. When the top hash (root hash) is available, the hash tree can be received form any non-trusted source.\nCurrently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks\n
Hash trees can be used to protect any kind of data stored, handled and transferred in and between computers.\nBefore downloading a file on a p2p network, the top hash is acquired from a trusted source. When the top hash (root hash) is available, the hash tree can be received form any non-trusted source.\nCurrently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks\n
Merkle trees are exchanged, if they disagree, Cassandra does a range-repair via compaction (using the Scuttlebutt reconciliation)\nTo ensure the data is still in sync even there is no READ and WRITE occurs to the data, replica nodes periodically gossip with each other to figure out if anyone out of sync. For each key range of data, each member in the replica group compute a Merkel tree (a hash encoding tree where the difference can be located quickly) and send it to other neighbors. By comparing the received Merkel tree with its own tree, each member can quickly determine which data portion is out of sync. If so, it will send the diff to the left-behind members.\n\nAnti-entropy is the "catch-all" way to guarantee eventual consistency, but is also pretty expensive and therefore is not done frequently. By combining the data sync with read repair and hinted handoff, we can keep the replicas pretty up-to-date.\n\nThe key difference in Cassandra's implementation of anti-entropy is that the Merkle trees are built per column family, and they are not maintained for longer than it takes to send them to neighboring nodes. Instead, the trees are generated as snapshots of the dataset during major compactions: this means that excess data might be sent across the network, but it saves local disk IO, and is preferable for very large datasets.\n
Merkle trees are exchanged, if they disagree, Cassandra does a range-repair via compaction (using the Scuttlebutt reconciliation)\nTo ensure the data is still in sync even there is no READ and WRITE occurs to the data, replica nodes periodically gossip with each other to figure out if anyone out of sync. For each key range of data, each member in the replica group compute a Merkel tree (a hash encoding tree where the difference can be located quickly) and send it to other neighbors. By comparing the received Merkel tree with its own tree, each member can quickly determine which data portion is out of sync. If so, it will send the diff to the left-behind members.\n\nAnti-entropy is the "catch-all" way to guarantee eventual consistency, but is also pretty expensive and therefore is not done frequently. By combining the data sync with read repair and hinted handoff, we can keep the replicas pretty up-to-date.\n\nThe key difference in Cassandra's implementation of anti-entropy is that the Merkle trees are built per column family, and they are not maintained for longer than it takes to send them to neighboring nodes. Instead, the trees are generated as snapshots of the dataset during major compactions: this means that excess data might be sent across the network, but it saves local disk IO, and is preferable for very large datasets.\n
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