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Note that range reads are supported natively by the database and have little cost over regular range reads.

This commit is contained in:
A.J. Beamon 2019-12-12 10:50:21 -08:00
parent bdc16def8e
commit 3cc3f1d2ad
5 changed files with 25 additions and 13 deletions
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3
bindings/go/src/fdb/range.go
View File

@ -54,7 +54,8 @@ type RangeOptions struct {
// Reverse indicates that the read should be performed in lexicographic
// (false) or reverse lexicographic (true) order. When Reverse is true and
// Limit is non-zero, the last Limit key-value pairs in the range are
// returned.
// returned. Reading ranges in reverse is supported natively by the
// database and should have minimal extra cost.
Reverse bool
}

24
bindings/java/src/main/com/apple/foundationdb/ReadTransaction.java
View File

@ -184,7 +184,9 @@ public interface ReadTransaction extends ReadTransactionContext {
* <i>first</i> keys in the range. Pass {@link #ROW_LIMIT_UNLIMITED} if this query
* should not limit the number of results. If {@code reverse} is {@code true} rows
* will be limited starting at the end of the range.
* @param reverse return results starting at the end of the range in reverse order
* @param reverse return results starting at the end of the range in reverse order.
* Reading ranges in reverse is supported natively by the database and should
* have minimal extra cost.
*
* @return a handle to access the results of the asynchronous call
*/
@ -205,7 +207,9 @@ public interface ReadTransaction extends ReadTransactionContext {
* <i>first</i> keys in the range. Pass {@link #ROW_LIMIT_UNLIMITED} if this query
* should not limit the number of results. If {@code reverse} is {@code true} rows
* will be limited starting at the end of the range.
* @param reverse return results starting at the end of the range in reverse order
* @param reverse return results starting at the end of the range in reverse order.
* Reading ranges in reverse is supported natively by the database and should
* have minimal extra cost.
* @param mode provide a hint about how the results are to be used. This
* can provide speed improvements or efficiency gains based on the caller's
* knowledge of the upcoming access pattern.
@ -263,7 +267,9 @@ public interface ReadTransaction extends ReadTransactionContext {
* <i>first</i> keys in the range. Pass {@link #ROW_LIMIT_UNLIMITED} if this query
* should not limit the number of results. If {@code reverse} is {@code true} rows
* will be limited starting at the end of the range.
* @param reverse return results starting at the end of the range in reverse order
* @param reverse return results starting at the end of the range in reverse order.
* Reading ranges in reverse is supported natively by the database and should
* have minimal extra cost.
*
* @return a handle to access the results of the asynchronous call
*/
@ -284,7 +290,9 @@ public interface ReadTransaction extends ReadTransactionContext {
* <i>first</i> keys in the range. Pass {@link #ROW_LIMIT_UNLIMITED} if this query
* should not limit the number of results. If {@code reverse} is {@code true} rows
* will be limited starting at the end of the range.
* @param reverse return results starting at the end of the range in reverse order
* @param reverse return results starting at the end of the range in reverse order.
* Reading ranges in reverse is supported natively by the database and should
* have minimal extra cost.
* @param mode provide a hint about how the results are to be used. This
* can provide speed improvements or efficiency gains based on the caller's
* knowledge of the upcoming access pattern.
@ -351,7 +359,9 @@ public interface ReadTransaction extends ReadTransactionContext {
* <i>first</i> keys in the range. Pass {@link #ROW_LIMIT_UNLIMITED} if this query
* should not limit the number of results. If {@code reverse} is {@code true} rows
* will be limited starting at the end of the range.
* @param reverse return results starting at the end of the range in reverse order
* @param reverse return results starting at the end of the range in reverse order.
* Reading ranges in reverse is supported natively by the database and should
* have minimal extra cost.
*
* @return a handle to access the results of the asynchronous call
*/
@ -375,7 +385,9 @@ public interface ReadTransaction extends ReadTransactionContext {
* <i>first</i> keys in the range. Pass {@link #ROW_LIMIT_UNLIMITED} if this query
* should not limit the number of results. If {@code reverse} is {@code true} rows
* will be limited starting at the end of the range.
* @param reverse return results starting at the end of the range in reverse order
* @param reverse return results starting at the end of the range in reverse order.
* Reading ranges in reverse is supported natively by the database and should
* have minimal extra cost.
* @param mode provide a hint about how the results are to be used. This
* can provide speed improvements or efficiency gains based on the caller's
* knowledge of the upcoming access pattern.

3
documentation/sphinx/source/api-c.rst
View File

@ -530,8 +530,7 @@ Applications must provide error handling and an appropriate retry loop around th
|snapshot|
``reverse``
If non-zero, key-value pairs will be returned in reverse lexicographical order beginning at the end of the range.
If non-zero, key-value pairs will be returned in reverse lexicographical order beginning at the end of the range. Reading ranges in reverse is supported natively by the database and should have minimal extra cost.
.. type:: FDBStreamingMode

4
documentation/sphinx/source/api-python.rst
View File

@ -287,7 +287,7 @@ A |database-blurb1| |database-blurb2|
If ``limit`` is specified, then only the first ``limit`` keys (and their values) in the range will be returned.
If ``reverse`` is True, then the last ``limit`` keys in the range will be returned in reverse order.
If ``reverse`` is True, then the last ``limit`` keys in the range will be returned in reverse order. Reading ranges in reverse is supported natively by the database and should have minimal extra cost.
If ``streaming_mode`` is specified, it must be a value from the :data:`StreamingMode` enumeration. It provides a hint to FoundationDB about how to retrieve the specified range. This option should generally not be specified, allowing FoundationDB to retrieve the full range very efficiently.
@ -503,7 +503,7 @@ Reading data
If ``limit`` is specified, then only the first ``limit`` keys (and their values) in the range will be returned.
If ``reverse`` is True, then the last ``limit`` keys in the range will be returned in reverse order.
If ``reverse`` is True, then the last ``limit`` keys in the range will be returned in reverse order. Reading ranges in reverse is supported natively by the database and should have minimal extra cost.
If ``streaming_mode`` is specified, it must be a value from the :data:`StreamingMode` enumeration. It provides a hint to FoundationDB about how the returned container is likely to be used. The default is :data:`StreamingMode.iterator`.

4
documentation/sphinx/source/api-ruby.rst
View File

@ -285,7 +285,7 @@ A |database-blurb1| |database-blurb2|
Only the first ``limit`` keys (and their values) in the range will be returned.
``:reverse``
If ``true``, then the keys in the range will be returned in reverse order.
If ``true``, then the keys in the range will be returned in reverse order. Reading ranges in reverse is supported natively by the database and should have minimal extra cost.
If ``:limit`` is also specified, the *last* ``limit`` keys in the range will be returned in reverse order.
@ -463,7 +463,7 @@ Reading data
Only the first ``limit`` keys (and their values) in the range will be returned.
``:reverse``
If true, then the keys in the range will be returned in reverse order.
If ``true``, then the keys in the range will be returned in reverse order. Reading ranges in reverse is supported natively by the database and should have minimal extra cost.
If ``:limit`` is also specified, the *last* ``limit`` keys in the range will be returned in reverse order.