DESCRIPTION: This change starts a maintenance deamon at the time of
server start if there is a designated main database.
This is the code flow:
1. User designates a main database:
`ALTER SYSTEM SET citus.main_db = "myadmindb";`
2. When postmaster starts, in _PG_Init, citus calls
`InitializeMaintenanceDaemonForMainDb`
This function registers a background worker to run
`CitusMaintenanceDaemonMain `with `databaseOid = 0 `
3. `CitusMaintenanceDaemonMain ` takes some special actions when
databaseOid is 0:
- Gets the citus.main_db value.
- Connects to the citus.main_db
- Now the `MyDatabaseId `is available, creates a hash entry for it.
- Then follows the same control flow as for a regular db,
When debugging postgres it is quite hard to get to the source for
`errfinish` in `elog.c`. Instead of relying on the developer to set a
breakpoint in the `elog.c` file for `errfinish` for `elevel == ERROR`,
this change adds the breakpoint to `.gdbinit`. This makes sure that
whenever a debugger is attached to a postgres backend it will break on
postgres errors.
When attaching the debugger a small banner is printed that explains how
to disable the breakpoint.
HasDistributionKey & HasDistributionKeyCacheEntry returns true when the
corresponding table has a distribution key, the comments state the
opposite,
which should be fixed.
Signed-off-by: Zhao Junwang <zhjwpku@gmail.com>
Co-authored-by: Onur Tirtir <onurcantirtir@gmail.com>
There was a bug reported for previous versions of Citus where
shard\_size was returning NULL for tables with spaces in them. It works
fine on the main branch though, but I'm still adding a test for this to
the main branch because it seems a good test to have.
During the creation of the devcontainer we need to add a ppa repository,
which is easiest done via software-properies-common. As turns out this
installes pkexec into the container as a side effect.
When vscode tries to attach a debugger it first checks if pkexec is
installed as this gives a nicer popup asking for elevation of rights to
attach to the process. However, since dev containers don't have a
windowing system running pkexec isn't working as expected and thus
prevents the debugger from attaching.
Without pkexec in the container vscode 'falls back' to plain old sudo
which we can run passwordless in the container.
For pkexec to be removed we need to first purge
software-propertied-common as well as autoremove all packages that were
installed due to the installation of said package. By performing this
all in one step we minimize the size of the layer we are creating.