qcache | In memory cache server with query capabilities | Caching library
kandi X-RAY | qcache Summary
kandi X-RAY | qcache Summary
In memory cache server with query capabilities
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Top functions reviewed by kandi - BETA
- Ensure that the cache is free
- Append a stat to the buffer
- Find the version number from a file
- Return a snapshot of the stats
- Reset the statistics
- Create a new QFrame from a dict
- Add stand - in columns to dataframe
- Returns the dtype of an object
- Unquote a string
- Query the dataframe
- Apply pandas filter
- Query dataframe
- Filter Pandas dataframe
- Return the decoded body
- Build docs
- Cleanup build files
- Evict key from cache
- Read content of a file
- Decompress a string
- Read content of file
- Construct a QFrame from a csv file
qcache Key Features
qcache Examples and Code Snippets
QPixmapCache.clear()
Community Discussions
Trending Discussions on qcache
QUESTION
I'm trying to use the QCache class, but method insert is missing...
SqlTableModel.h
...ANSWER
Answered 2018-Dec-07 at 13:13Your problem is that getValue
is const
function, while insert
of QCache
is not const
.
You can make your function non const, or mark m_cache
with mutable
, or create different functions for insert and get.
QUESTION
How is spatial join query executed among the nodes in PARTITIONED mode? As Ignite partition the data (default 1024) among the nodes using Rendezvous Affinity hashing, how is join operation executed among the partitions? Suppose I have two spatial datasets in the cache (pCache and qCache), each contains 10 partitions(1, .., 10). How is ignite perform the join operation on this two dataset? Is it partition1 of pCache with partition1 of qCache?
My second question: How is ignite perform the same operation in case of distributed join?
...ANSWER
Answered 2018-Oct-02 at 07:42There is no correspondence between partitions of different caches. If you run a join operation, then by default only local lookup will be performed.If data is not collocated, then this approach may give you a partial result.
When all-to-all mapping is performed, then every node has to communicate with every other node, so messages are totally sent in the cluster, where is the number of nodes. This is called distributed joins, and it affects performance significantly. It may be enabled either in the connection string in case of JDBC driver, or by using SqlFieldsQuery#setDistributedJoins(...) method in case of cache query API.
The recommended way to do joins is to collocate the data in a way, that no distributed joins are needed. Ignite has a feature called affinity collocation, designed specially for this purpose. You can specify a field of an object, that will be used to calculate the affinity function. Value of this field doesn't have to be unique, but it should be a part of a key. So, if you want to perform joins on two tables, you may collocate them by affinity, so no distributed joins will be needed.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install qcache
You can use qcache like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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