updating documentation

This commit is contained in:
2021-09-28 00:29:41 +01:00
parent c481c1a976
commit 8a0d8085a2
7 changed files with 28 additions and 23 deletions

View File

@@ -21,7 +21,7 @@ The mapping table takes each row and creates a `(key,value)` pair with:
- The key being the id across all columns (`id_all_columns`).
- The value being the raw data as an array.
The mapping table is then condensed to a single dictionary with these key, value pairs and is used as a side input further down the pipeline.
The mapping table is then condensed to a single dictionary with these key, value pairs (automatically deduplicating repeated rows) and is used as a side input further down the pipeline.
This mapping table is created to ensure the `GroupByKey` operation is as quick as possible. The more data you have to process in a `GroupByKey`, the longer the operation takes. By doing the `GroupByKey` using just the ids, the pipeline can process the files much quicker than if we included the raw data in this operation.

View File

@@ -64,7 +64,7 @@ We strip all leading/trailing whitespace from each column to enforce consistency
Some of the data is repeated:
- Some rows repeated, with the same date + price + address information but with a unique transaction id.
- Some rows are repeated, with the same date + price + address information but with a unique transaction id.
<details>
<summary>Example (PCollection)</summary>
@@ -87,7 +87,7 @@ Some of the data is repeated:
]
},
{
"fd4634faec47c29de40bbf7840723b41": [
"gd4634faec47c29de40bbf7840723b42": [
"317500",
"2020-11-13 00:00",
"B90 3LA",