columnar | High-throughput columnar serialization in Rust
kandi X-RAY | columnar Summary
kandi X-RAY | columnar Summary
This is a pretty simple start to columnar encoding and decoding in Rust. For the moment it just works on integers (unsigned, signed, and of varying widths), pairs, vectors, options, and combinations thereof. Some extensions are pretty obvious (to other base types, tuples of other arities), and you can implement the trait for your own structs and enumerations with just a bit of copy/paste, but I'll need to get smarter to handle these automatically.
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Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of columnar
columnar Key Features
columnar Examples and Code Snippets
private static Object[][] tableBuilder(String word) {
Object[][] table = new Object[numberOfRows(word) + 1][keyword.length()];
char[] wordInChards = word.toCharArray();
// Fils in the respective numbers
table[0] = find
public static String encrpyter(String word, String keyword) {
ColumnarTranspositionCipher.keyword = keyword;
abecedariumBuilder(500);
table = tableBuilder(word);
Object[][] sortedTable = sortTable(table);
Strin
public static String encrpyter(String word, String keyword, String abecedarium) {
ColumnarTranspositionCipher.keyword = keyword;
ColumnarTranspositionCipher.abecedarium = Objects.requireNonNullElse(abecedarium, ABECEDARIUM);
t
Community Discussions
Trending Discussions on columnar
QUESTION
I have 10 files which contain one columnar vertical data that i converted to consolidate one file with data in horizontal form
file 1 :
...ANSWER
Answered 2021-Jun-06 at 10:08I assume it is indeed from an empty line. You could remove such 'mistakes' by
updating your script to include sed 's/,""$//'
like:
QUESTION
I have a scenario where in my directory their are 10 files
each file as one columnar record like below
file1 :
...ANSWER
Answered 2021-Jun-04 at 16:15Use paste
.
Also, since you're writing CSV, you want to escape any double quotes that exist in the original data
QUESTION
I often take the columnar output of some command and pipe it to awk
and xargs
to perform some action that I want. A good example of this would be taking the output of docker ps
, fetching the container IDs, and removing those containers. I understand that there are easier ways to do this with Docker, but in my case I want to post-process the list so I'm doing it the hard way. Anyway, the command looks something like docker ps -f status=exited | tail -n +2 | awk '{ print $1 }' | xargs docker rm
. If I run this command directly, it works ok if there are containers that match. If the list is empty, however, awk
still tries to pipe an empty string to xargs
. This results in an error from docker rm
that looks like this...
ANSWER
Answered 2021-Jun-02 at 04:33As per the manual, xargs takes -r
flag, which prevents running the command for an empty list.
QUESTION
I'm new to python an I want to improve several excel programs I've made using VBA. Like the one below. I have a machine log which is consist of 2 Columns and average of 50,000 Rows, every group is separated by spaces. Sample:
and i want to transform it to this columnar per group.
I don't need the 1st column, what I only need is the 2nd columns to be transformed. I already made it thru VBA in excel but it took 2-5 mins to transform 50,000 rows.
I've been self learning python for a while and I hope it will speed up the process thru pandas or numpy.
Thanks a lot.
...ANSWER
Answered 2021-May-27 at 09:37Input data:
QUESTION
We have a client who is shipping Subscription products (which are actually Composite products with four to five Bundles of products in them) and they offer delivery on a weekly basis. Their delivery date is always Thursdays. Woocommerce Subscriptions allows for synchronization to a specific date, so we've chosen the "Align Subscription Renewal Day" option and, in a given Product, we've set it to go on Thursdays for each option ("every 4th week", "every 3rd week", etc.)
The caveat with our situation is that orders received the day before (Wednesday) or on the Thursday itself can't be fulfilled that week and need to have their start date/delivery date bumped to the following Thursday. To that end, we've written a function for functions.php
using the woocommerce_subscriptions_product_first_renewal_payment_time
hook:
ANSWER
Answered 2021-May-17 at 20:07There is a function exposed by the WC_Subscription
object called update_dates()
which takes an array of date keys matching the values used in the Subscriptions list dashboard (and other areas).
The function signature is WC_Subscription::update_dates( $dates, $timezone )
. I believe an object must be instantiated; I don't think this method can be called statically. Subscriptions function reference here.
The documented parameters (as keys to be passed in the $dates
array) are:
start
trial_end
next_payment
last_payment
end
The array itself is required, but I don't believe each individual key needs to be populated with a value. For instance, default orders generated by the Subscriptions plugin often have no trial_end
or end
dates (unless separately configured that way).
Using an action hook such as woocommerce_checkout_subscription_created
(Subscriptions action reference) you could use the $subscription
argument, which is an instance of WC_Subscription
, and do something like:
QUESTION
I try to understand indexes in Azure Synapse and I'm a bit confused by some of them.
Regarding the Clustered Columnstore Index, I've a feeling that it works a bit like Apache Parquet, with row groups and column chunks inside. In heap tables the data is not indexed, so it seems pretty clear too.
But what about the clustered and nonclustered indexes? The documentation defines them as:
Clustered indexes may outperform clustered columnstore tables when a single row needs to be quickly retrieved. For queries where a single or very few row lookup is required to perform with extreme speed, consider a clustered index or nonclustered secondary index. The disadvantage to using a clustered index is that only queries that benefit are the ones that use a highly selective filter on the clustered index column. To improve filter on other columns, a nonclustered index can be added to other columns. However, each index that is added to a table adds both space and processing time to loads.
Here are my questions:
- Does it mean they're more like the indexes from SQL Server? I mean, the clustered index would order the data by one column and store it as rows? And the non clustered would be an extra sorted index storing only references to the rows?
- If my assumption about row-based format is correct, does it mean the clustered index is not performant for the analytical queries, doesn't it?
- What happens if we create a table with both Columnstore and Clustered Indexes? The data is duplicated, once for the columnar format, once for the row format?
Some links I found on that topic, but still have some doubts whether they apply to Synapse:
- https://crmchap.co.uk/understanding-table-distribution-index-types-in-azure-synapse-analytics/
- https://www.sqlservercentral.com/articles/introduction-to-indexes-part-2-%e2%80%93-the-clustered-index
- https://www.sqlservercentral.com/articles/introduction-to-indexes-part-3-%E2%80%93-the-nonclustered-index
- https://docs.microsoft.com/en-us/sql/t-sql/statements/create-table-azure-sql-data-warehouse?toc=%2Fazure%2Fsynapse-analytics%2Fsql-data-warehouse%2Ftoc.json&bc=%2Fazure%2Fsynapse-analytics%2Fsql-data-warehouse%2Fbreadcrumb%2Ftoc.json&view=azure-sqldw-latest&preserve-view=true#rowstore-table-heap-or-clustered-index
ANSWER
Answered 2021-May-05 at 14:50Bartosz,
Does it mean they're more like the indexes from SQL Server? I mean, the clustered index would order the data by one column and store it as rows? And the non clustered would be an extra sorted index storing only references to the rows?
You are correct on clustering and non clustering definition - with a slight twist. It is similar to traditional SQL Server and that the leaf of cluster is the actual data row. In summary, the physical organization of data rows for Synapse/pdw will be
Clustered columnstore - data is not sorted and row segments can have overlapping min-max values
Clustered columstore with order by - data is sorted, hence the row segments will not have overlapps and skipping will optimal
Heap - which is row format
Clustered index this is SQL Server clustered index where lead/data portion is sorted.
If my assumption about row-based format is correct, does it mean the clustered index is not performant for the analytical queries, doesn't it?
Clustered index will be performant if your query selects a set of values are sequential. for example - select * from table where year between 2005 and 2007
. Row/Heap tables are efficient if your projection/select includes all or most of the columns of the table. Columnstore organization is efficient if have wide tables and select a handful of columns.
What happens if we create a table with both Columnstore and Clustered Indexes? The data is duplicated, once for the columnar format, once for the row format? If you have a columstore index, you wont be able to create a clustered index.
QUESTION
ANSWER
Answered 2021-Mar-13 at 17:33Not so sure what you want to do with the -1 , assuming you get your labels back like this:
QUESTION
I have this data frame and table:
...ANSWER
Answered 2021-Mar-26 at 09:06Extract the legend as grob, then use layout matrix, see example:
QUESTION
Keeping in mind that Redshift is a columnar database server,Lets say I have a table A with 50 columns and I need to join it with table B but I need only 10 columns from table A in my final join result. Lets say table C is a temp table created from Table A with the 10 columns I need.
- Will [ Table C join Table B] be faster than [Table A join Table B]
- Assuming Table A was a temporary table itself (derived from other tables), will your response to #1 still hold ?
ANSWER
Answered 2021-Mar-11 at 12:52Redshift does have other optimizations beyond just storing columns separately.
That said, I would expect very similar performance between referencing all 10 columns in a single table versus referencing 10 columns from a table with more columns. It is hard to think of optimizations that would would be affected by unreferenced columns.
I don't understand the second part of the question. A table is a table, whether temporary or not. If you mean "Is there a performance difference between a temporary table and running a subquery/CTE?". Then yes, there is definitely a difference. For instance, there is overhead in creating a table, storing the data, and re-reading it. On the other hand, the optimizer might choose a better execution plan for the temporary table -- that is not typical, but it happens.
QUESTION
I need to extract substrings from a file into a new file. Mac or Linux.
The data is between the 4th and 5th "|" symbol.
...ANSWER
Answered 2021-Mar-01 at 05:29Converting my comment to answer so that solution is easy to find for future visitors.
There are 2 ways to get it:
Any awk version:
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