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Index messages with attachments using a boolean

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When indexing message attachment metadata using numeric indexes such as:

```javascript
{
  conversationId: '+12223334455',
  received_at: 123,
  attachments: […],
  numAttachments: 2,
},
{
  conversationId: '+12223334455',
  received_at: 456,
  attachments: [],
  numAttachments: 0,
}
{
  conversationId: '+12223334455',
  received_at: 789,
  attachments: [],
  numAttachments: 1,
}
```

It creates an index as follows:

```
[conversationId, received_at, numAttachments]
['+12223334455', 123, 2]
['+12223334455', 456, 0]
['+12223334455', 789, 1]
```

This means a query such as…

```
lowerBound: ['+12223334455', 0,                1               ]
upperBound: ['+12223334455', Number.MAX_VALUE, Number.MAX_VALUE]
```

…will return all three original entries because they span the `received_at`
from `0` through `Number.MAX_VALUE`. One workaround is to index booleans using
`1 | undefined` where `1` is included in the index and `undefined` is not, but
that way we lose the ability to query for the `false` value. Instead, we flip
adjust the index to `[conversationId, hasAttachments, received_at]` and can
then query messages with attachments using

```
[conversationId, 1 /* hasAttachments */, 0                /* received_at */]
[conversationId, 1 /* hasAttachments */, Number.MAX_VALUE /* received_at */]
```
This commit is contained in:
Daniel Gasienica 2018-04-13 21:47:06 -04:00
parent c46e1a1519
commit 9d84b2f420
7 changed files with 42 additions and 26 deletions
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8
js/modules/migrations/18/index.js
View file

@ -2,14 +2,14 @@ exports.run = (transaction) => {
const messagesStore = transaction.objectStore('messages');
[
'numAttachments',
'numVisualMediaAttachments',
'numFileAttachments',
'hasAttachments',
'hasVisualMediaAttachments',
'hasFileAttachments',
].forEach((name) => {
console.log(`Create message attachment metadata index: '${name}'`);
messagesStore.createIndex(
name,
['conversationId', 'received_at', name],
['conversationId', name, 'received_at'],
{ unique: false }
);
});