Allow order by on non-indexed fields #1961
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| @@ -75,3 +80,8 @@ func (opts *Options) WithMultiDBHandler(multidbHandler MultiDBHandler) *Options | |||
| opts.multidbHandler = multidbHandler | |||
| return opts | |||
| } | |||
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| func (opts *Options) WithSortBufferSize(size int) *Options { | |||
| opts.sortBufferSize = size | |||
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we should document it - what it is, what will increase of this value provide, what if we will set to 0
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Added validity check and description
| } | ||
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| if sortingIndex == nil { | ||
| return nil, ErrNoAvailableIndex |
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this could potentially affects current users code, should be communicated somehow
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Updated doc: codenotary/immudb.io#510
Razikus
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Razikus
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Apr 18, 2024
Razikus
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Apr 26, 2024
Signed-off-by: Stefano Scafiti <[email protected]>
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This merge request is meant to support the order by clause on non indexed fields.
If the query planner determines that the output is not already sorted, then an additional sorting step is added through a new type of reader:
sortReader.When the client attempts to read the first row on the sort reader, all rows gets fetched from the underlying reader and collected to a buffer. When the buffer contains at least 1024 rows, sorting is performed in memory and the sorted chunk is spilled to a temporary disk file. The process continues until all the result rows have been read.
At this point, sorted disk chunks (if any) are merged into a single bigger sorted chunk and a reader to such a file is returned to the client. If the output contains a number of rows <= 1024, then a reader to the buffer is simply returned.