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Fastest way to count exact number of rows in a very large table?
...db_partition_stats st
WHERE
object_name(object_id) = 'MyBigtable' AND (index_id < 2)
2 runs, both under 1 second, count = 1,401,659,670
The second one has less rows = wrong. Would be the same or more depending on writes (deletes are done out of hours here)
...
After array_filter(), how can I reset the keys to go in numerical order starting at 0
...aceholder starting from 0, but unfortunately it still retains the original index. I looked for a while and couldn't see anything, perhaps I just missed the obvious, but my question is...
...
When to use std::size_t?
... in C++. By extension it is also guaranteed to be big enough for any array index so it is a natural type for a loop by index over an array.
If you are just counting up to a number then it may be more natural to use either the type of the variable that holds that number or an int or unsigned int (if...
Unique constraint on multiple columns
...lumn unique constraint to an existing table.
Under the table, right click Indexes->Click/hover New Index->Click Non-Clustered Index...
A default Index name will be given but you may want to change it. Check the Unique checkbox and click Add... button
Check the columns you want included
...
Convert Array to Object
...se an accumulator aka reduce.
['a','b','c'].reduce(function(result, item, index, array) {
result[index] = item; //a, b, c
return result;
}, {}) //watch out the empty {}, which is passed as "result"
Pass an empty object {} as a starting point; then "augment" that object incrementally.
At the e...
How to store date/time and timestamps in UTC time zone with JPA and Hibernate
...
@Override
public void set(PreparedStatement st, Object value, int index) throws SQLException {
Timestamp ts;
if(value instanceof Timestamp) {
ts = (Timestamp) value;
} else {
ts = new Timestamp(((java.util.Date) value).getTime());
}
...
Why is quicksort better than mergesort?
...eks to disk. For instance this is why it is standard advice that you drop indexes before doing large data loads in databases, and then rebuild the index later. Maintaining the index during the load means constantly seeking to disk. By contrast if you drop the indexes, then the database can rebuil...
Reading/parsing Excel (xls) files with Python
...e
worksheet = workbook.sheet_by_name('Name of the Sheet')
open sheet by index
worksheet = workbook.sheet_by_index(0)
read cell value
worksheet.cell(0, 0).value
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What is the difference between “JPG” / “JPEG” / “PNG” / “BMP” / “GIF” / “TIFF” Image?
...ively worse and worse.
There are also different colour depths (palettes): Indexed color and Direct color.
With Indexed it means that the image can only store a limited number of colours (usually 256) that are chosen by the image author, with Direct it means that you can store many thousands of co...
Sorted collection in Java
... search and move).
However, unlike a List, PriorityQueue does not support indexed access (get(5)), the only way to access items in a heap is to take them out, one at a time (thus the name PriorityQueue).
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