Always capture timestamps, even if it is the same. This is because we are dependent
on it later on in the repo update process. Specifically, when updating from a HTTP
server that doesn't send out etags with its responses, it will trigger a full blown
repo update every time, even if all the values in the index are the same (name,
description, etc). This is as distinct from better behaving servers that send etags,
in which case we will only do a partial update (i.e. persist the "last updated time").
In such a case, the remainder of the update process will proceed, and ask for this
timestamp.
In a recent commit, I cleaned up the code which deletes repo. At that point,
instead of maybe concatenating strings together, sometimes with an `AND` statement,
it was changed to use the slightly better `QuerySelection`. This class is
preferable because it doesn't need the developer to know whether there was
any previous constraints, and thus it knows whether to prepend an `AND`.
The problem arose because `QuerySelection` is effectively an immutable class.
Calling `add()` on it returns a new copy with a different set of constraints.
The code which deleted the repo did not use this copy, and thus the resulting
query had zero constraints.
The fix is to use the return value of `add()` correctly. It would've been
easier to identify this bug if we had a lint check for "unused return values",
though it is likely that that would get annoying very quickly.
Fixes#717.
Use an integer primary key to join `fdroid_app` and `fdroid_apk` rather than the apps package name.
**Disclaimer:**
I realise this is a big change, but it needs to be done at some point, and it is not amenable to smaller changes, due to the fact that the app/apk relationship is so ingrained throughout F-Droid. Luckily, we have really quite comprehensive test coverage of the F-Droid `ContentProvider`s which helps to confirm that nothing should be majorly broken here.
**Some points of note:**
This is the first part of implementing #511, whereby the DB is refactored to better support multiple repositories.
Instead of joining `fdroid_app` and `fdroid_apk` tables using the package name, join based on an integer id autogenerated by sqlite. By default sqlite calls this `rowid` and it exists for every table, unless you've specified your own `NUMBER AUTO INCREMENT PRIMARY KEY` field. We have not done this for `fdroid_app`, so `rowid` is indeed the key we use in this MR. The package name was previously `id` in both the app and apk tables. Now `fdroid_app` makes use of `rowid` and `fdroid_apk` has a foreign key called `appId`.
The `ApkProvider` used to get away with only really querying the `fdroid_apk` table, and thus it didn't have to prefix any of the field names in the query with the table name. However now it always joins onto the `fdroid_app` table also, and as such, there are many places where field names needed to be prefixed with the table name (e.g. the `apk` alias or the `app` alias) to ensure the SQL is unambiguous when fields with the same name exist in both tables. The catch is, we want to reuse helper functions that build fragments of SQL, such as "Query based on package name". These helper functions are used both when updating and deleting apks (where field table prefixes are not allowed) and also in select statements (where they are required). Thus this changes comes with an `includeTableAlias` argument added to many of these methods (e.g. `ApkProvider.queryApp`).
There is still a package name column in the `fdroid_apk` table (the `id` field). This will be removed in future MRs and replaced with the package name from the joined `fdroid_app` table.
The `RepoPersister` used to dump apps in the db, then dump apks into the db. Now it needs to be a bit more nuanced, and dump apps into the db, _then ask the db what `rowid` was assigned to the apps_. This is then used when dumping the apks into the db. This also required some changes to how the `TempAppProvider` and `AppProvider` interact. In the interests of reusing code, both of these are able to provide operations on a similarly structured table but one is an in memory table (`temp_fdroid_app`) and the other is on disk (`fdroid_app`). In the past this was simpler, because the only interaction with the `TempAppProvider` was by using lists of `ContentOperation`s. Whereas now that we need to ask more substantial questions of the `TempAppProvider` other than "Insert this thing" or "update that thing", we needed to implement the `query` method in `TempAppProvider` similar to how it is in the base class `AppProvider`. As such, the common code for the base class and subclass `query` methods was extracted into `AppProvider.runQuery()`.
I tried to minimize the changes to the test suite as much as possible, so that it is possible to verify that they pass under the same conditions as before this change. However some changes were required to support the notion that apks depend on an app and its rowid, whereas this was not the case before. Thus there is some more boilerplate in the tests to ensure that inserting an apk ensures an app entry is present in the db too.
See merge request !345
Moved index adding to a helper function, so that the same mistake isn't made
again. That is, indexes should be the same whether upgrading or creating a
database. Thus, the code to add indexes should always be the same regardless
of the reason for an index being added. The `IF NOT EXISTS` syntax helps
to allow the same queries to add during creatin and migration of database.
The fact that sqlite chose to do a "FULL TABLE SCAN" right off the bat when showing a list
of apps results in it having to do extra work at the end of the query to sort. If the scan
can be utilise an index, then the sorting is already done and a b-tree need not be constructed.
Thus, this introduces indexes for both the `name` column (used to sort most lists of apps)
and the `added` column (used to figure out the `Whats New` apps).
This is required because SQLite "rowids" are 64 bit integers:
> all rows within SQLite tables have a 64-bit signed integer
> key that uniquely identifies the row within its table."
https://sqlite.org/lang_createtable.html#rowid
This is important for the ability to refactor the database for better performance in the future.
See #511 for details.
For those interested in the details, here is a query plan of selecting the "All" category of apps before
this commit:
* `SCAN TABLE fdroid_app USING INDEX app_id`
* `SEARCH TABLE fdroid_apk USING INDEX apk_id (id=?)`
* `SEARCH TABLE fdroid_repo USING INTEGER PRIMARY KEY (rowid=?)`
* `SEARCH TABLE fdroid_installedApp AS installed USING INDEX sqlite_autoindex_fdroid_installedApp_1 (appId=?)`
* `SEARCH TABLE fdroid_apk AS suggestedApk USING INDEX sqlite_autoindex_fdroid_apk_1 (id=? AND vercode=?)`
* `USE TEMP B-TREE FOR ORDER BY`
And here is a query plan of afterwards:
* `SCAN TABLE fdroid_app`
* `SEARCH TABLE fdroid_apk USING INDEX apk_appId (appId=?)`
* `SEARCH TABLE fdroid_repo USING INTEGER PRIMARY KEY (rowid=?)`
* `SEARCH TABLE fdroid_installedApp AS installed USING INDEX sqlite_autoindex_fdroid_installedApp_1 (appId=?)`
* `SEARCH TABLE fdroid_apk AS suggestedApk USING INDEX apk_appId (appId=?)`
* `USE TEMP B-TREE FOR ORDER BY`
The things of note are:
* `SCAN TABLE` doesn't use an index, which means that it is really using the rowid index. Shouldn't behave much differently.
* The second item now uses an integer primary key index rather than a package name index. Should increase search speed marginally which was the goal of this commit. As more apks exist, the speed improvement will also increase.
This class is used by `AppDetails` without an API verison check around its access.
Thus, we call methods on this that are unsupported when on gingerbread.
By removing `TargetApi` from the class, it unearthed a couple of locations
where methods were being invoked without first guarding against the build version
correctly. These two locations have been fixed and a `TargetApi` attached to the
more narrowly defined method which requires it.
SQLite has a very nice "EXPLAIN QUERY PLAN" command (https://sqlite.org/eqp.html).
It is not really meant to be used in production code, as per the docs, but it is
super helpful at diagnosing missing indexes or other performance problems with
databases. I find it much better than, for example, the MySQL alternative.
This commit routes queries from the `ApkProvider` and `AppProvider` through a
`LoggingQuery` which (in debug builds) times queries, and if they take longer
than a certain threshold, outputs them to logcat. In addition, it will then
ask sqlite to explain its query plan for that same query, and output that to
logcat too.
Refactor database schema constants
**Note:** When this is merged I'll rebase !347 and remove its WIP.
## Summary
In order to do the database changes required for #511, I've found that it is difficult due to my inclination to switch between referring to database columns by either a Java constant such as `AppProvider.DataColumns.NAME` and string literals such as `"name"`. All string literals should be migrated to constants, and that will happen in my next MR. In order to prepare for this, I've gathered together the constants into one common place: `org.fdroid.fdroid.data.Schema`. This is going to be the authoritative place for the schema to be stored going forward, and will help when reasoning about the database structure.
Although it seems large, this change is a fairly straightforward find/replace job. It also passes all tests for which there is good test coverage in the content providers.
## Changes
Create `Schema` interface to make it simpler to replace string literals with constants.
Right now, table names are in `DBHelper.TABLE_*` constants, and each tables fields are
in `*Provider.DataColumns.*` constants. This brings them all into a predictable location.
In addition, it makes it easier to statically import `Schema` so that instead of, e.g.,
* `AppProvider.DataColumns.PACKAGE_NAME`
We can choose one of the following, based on our current context:
* `Schema.AppTable.Cols.PACKAGE_NAME`
* `AppTable.Cols.PACKAGE_NAME`
* `Cols.PACKAGE_NAME`
In the worst case, it isa couple of chars shorter than now. In the best case, if we are
writing a class that primarily deals with Apps (e.g. App.java or AppProvider.java) then
we get a big win with just `Cols.PACKAGE_NAME`.
Having these things slightly shorter may seem like it is pointless, but the length of
each constant probably contributed to my lack of willingness to use constants instead
of string literals when constructing queries.
In the future, this should be moved towards something more akin to:
> http://openhms.sourceforge.net/sqlbuilder/
and I hope that extracting all the schema stuff into one interface may help that.
See merge request !346
Right now, table names are in `DBHelper.TABLE_*` constants, and each tables fields are
in `*Provider.DataColumns.*` constants. This brings them all into a predictable location.
In addition, it makes it easier to statically import `Schema` so that instead of, e.g.,
* `AppProvider.DataColumns.PACKAGE_NAME`
We can choose one of the following, based on our current context:
* `Schema.AppTable.Cols.PACKAGE_NAME`
* `AppTable.Cols.PACKAGE_NAME`
* `Cols.PACKAGE_NAME`
In the worst case, it isa couple of chars shorter than now. In the best case, if we are
writing a class that primarily deals with Apps (e.g. App.java or AppProvider.java) then
we get a big win with just `Cols.PACKAGE_NAME`.
Having these things slightly shorter may seem like it is pointless, but the length of
each constant probably contributed to my lack of willingness to use constants instead
of string literals when constructing queries.
In the future, this should be moved towards something more akin to:
> http://openhms.sourceforge.net/sqlbuilder/
and I hope that extracting all the schema stuff into one interface may help that.
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java.lang.NullPointerException
at org.fdroid.fdroid.Utils.clearOldFiles(Utils.java:347)
at org.fdroid.fdroid.CleanCacheService.onHandleIntent(CleanCacheService.java:51)
at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:194)
at android.os.HandlerThread.run(HandlerThread.java:60)
Also change the overrides from onCreate to init as suggested in the
changelog:
https://github.com/ACRA/acra/wiki/ChangeLog#acra-490-rc-1-2-may-2016
The behaviour should be very similar, although overriding the wrong
method (which we were doing) could cause all sorts of weird issues.
This is currently baffling me as to how it can happen. This isn't a pretty
fix but it is better that letting F-Droid crash. db9bdc31 was supposed to
make it so that only one thread at a time ever updated the static vars on
FDroidApp.
closes#690
UpdateService.onHandleIntent() starts with a time check for whether an
update is actually scheduled. Before, UpdateService put up a notification
when it started. This changes it so that the notification is put up after
the check, so it should only show the notification if UpdateService is
actually going to run, and no longer when it is just waking up to check the
time.
!307#662
