Couchbase First Impressions (architectural features)
Byte stream for document saving always has a document ID (OBJECT_ID)
High concurrency, high flexibility, high scalability, and good fault tolerance
Document-oriented cluster storage system
Each document with a unique doc ID
Balanced load
Buckets vs VBuckets1. Buckets
Couchbase Storage logic unit is called bucket
the mappings, especially because it does not guarantee that the order is constant.It is assumed that the hash function distributes elements appropriately between buckets, providing stable performance for basic operations (get and put). The time required to iterate the collection view is proportional to the capacity of the HashMap instance (the number of buckets) and its size (number of key-value mappings).
H [0 .. n-1]
2) swap the beginning (maximum) and end of the heap
3) Reduce the heap size by 1 and call shift_down (0) to adjust the top data of the new array to the corresponding position.
4) Repeat Step 2 until the heap size is 1.
Details: heap sortingAlgorithm 8: Base sorting
Base sorting is a non-Comparative integer Sorting Algorithm. The principle is to cut an integer into different digits by the number of digits and then compare them by each digit. Since integers can also express strings (
conceptually simple, this approach is not scalable. The time wheel is a buckets collection, where each bucker represents a time block in the future when the timer expires. These buckets are defined using a logarithmic time based on 5 buckets. Using Jiffies as a time granularity, several groups are defined that represent future expiration periods, where each grou
sort is to convert the input data value into a key stored in an additional array space. As a sort of linear time complexity, counting ordering requires that the input data be an integer with a definite range.1. Motion Diagram Demo2. Python Code Implementation def countingsort (arr, maxValue): bucketlen = maxvalue+ 1 bucket = [ 0]*bucketlen sortedindex = 0 arrlen = Len (arr) for I in range (Arrlen): , if not Bucket[arr[i]: bucket[arr[i]]= 0 bucket[arr[i]]+=
Bucket sort ( bucket sort) or so-called box sorting is a sort algorithm that works by splitting an array into a finite number of buckets. Each bucket is sorted separately (it is possible to use a different sorting algorithm or recursively continue to sort by using the bucket sort). Bucket sequencing is an inductive result of pigeon nest sorting. When the values in the array to be sorted are evenly distributed, the bucket is sorted using linear time (Θ
implemented index, but by creating an additional 2 arrays to implement the indirect index, that is int[] buckets and entry[] Entries two arrays (that is, the buckets is actually the subscript of the entries array), here is the second dictionary and hash Table difference, remember the hash conflict ? Yes, the second difference is that the strategy for dealing with hash conflicts is different ! The dictiona
~999, of course, the case of conflict, this is the hash conflict (hash collisions) . Pull away, about the specific implementation of the principle or to see the small bastard recommended blog bar, of course, that blog above that big turn word is also pretty dazzling ... Back to Dictionary, the minimum prime number that is not less than the value is used as the actual capacity it uses, and the minimum is 3. "(Lao Zhao), when the actual capacity is not directly implemented index, but by creating a
cardinality sorting algorithm performs the correct sorting of these numbers in θ (d (n+k)) time.4, bucket sortingThe count sort assumes that the input is made up of integers in a small range, while the bucket ordering assumes that the input is produced by a random process that distributes the elements evenly and independently across the interval [0,1]. When the input of the bucket sort conforms to the uniform distribution, it can be expected to run linearly. The idea of barrel sequencing is: Di
article, tell Blizzard how to improve the hash table. In the above hashing algorithm there is a "Seed2 + (Seed2
The core of the above Blizzard hashing algorithm is as follows (I assign the simplest value to crypttable and set the Dwhashtype to 1):
Inline UINT Cmymap::hashkey (LPCTSTR key) const
{
int dwhashtype = 1;
unsigned long seed1 = 0x7fed7fed, seed2 = 0xEEEEEEEE;
int ch;
while (*key! = 0)
{
ch = toupper (*key++);
seed1 = crypttable[(dwhashtype Seed1 = ((Dwhashtype SEED2 = ch + seed1
auxiliary spaces, one is the 0~9 bucket, the other is an array of computed positioning, and what is the positioning array? is to record where the data in each bucket will be put back in the original array.def radixsort (Number:array[int], d:int): Unit = {//D Indicates the maximum number of bits var k = 0 var n, m = 1 //Control key value sorted by which VA L TEMP = Array.ofdim[int] (ten, number.length) //The first dimension of the array represents the possible remainder 0-9 val
Aggregation is used to analyze the statistical indicators of the query result set, we take the View log analysis as an example to introduce a variety of commonly used elasticsearch aggregation operations.
Directory:
Query the number of users to watch and watch the length of video
Aggregation Page Splitter
Querying video Uvs
Single Video UV
Bulk query for video Uvs
Having query
Filtering based on Count
Filtering according to other indicators
row Source 2 (Match table), the connection operation for each of the data in the column using the same hash function and find the corresponding a in the position of the data in the Hash table, in that position to check whether the matching data can be found----------------extended reading: Hash table related----------------Hash table, which is a data structure that is accessed directly by key.That is, it accesses the record by mapping the key to a location in the table to speed up the lookup.Ex
detail because it will soon be improved in the next method. More details for interested readers can read the original paper.
Now we have a really bad bit-estimation method. What improvements can we make? A straightforward idea is to use multiple independent hash functions. If each hash function outputs its own random data set, we can record the longest leading 0-bit sequence. And then at the end we can get an average for a more accurate estimate.
This gives us a fairly good result from the expe
This section describes freelists and sharedpoollrulist. freelist idle list is divided by bucket. There are a total of 255 buckets. bucket0 --- bucket254 each bucket has a chunklist; freelists have unused chunkRESERVEDFREELISTS: the number of buckets on RESERVEDFREELISTS is 15.
This section describes free lists and shared pool lru list. the free list idle list is divided by bucket. There are a total of 255
O (Nlogn). But there are also linear time complexity of the ordering, but there is a precondition, is to be sorted to meet a certain range of the number of integers, and the counting order needs more auxiliary space. The basic idea is to count the number of each number as the subscript of the counting array with the numbers to be sorted. Then the output sequence can be ordered sequentially.Implementation code:/** * @Description:Bucket sortBucket sorting is a kind of improvement and generalizati
.
Below is a section of code for ENTRYStatic class Entry {final K key; V value; Entry next; int hash, ...}HashMap stores data in multiple unidirectional entry lists (sometimes referred to as bucket buckets or container orbins). All lists are registered in a Entry array (entryThe following illustration depicts an internal storage of an HashMap instance that contains an array of nullable objects. Each object is connected to another object, which ma
Remove key-value pair elements by key
The interface of the main collection is finished, let's look at the specific collection type below.Associative generic collection Class 1. Dictionary
The time it takes for Dictionary
to query data is the fastest in all collection classes, because its internal use of hash function plus a set of arrays to achieve, so its query data operation time complexity can be considered O (1). The implementation of Dictionary
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