This patch locks down search_path in extension install and update
scripts to only contain pg_catalog, this requires that any reference
in those scripts is fully qualified. Additionally we add explicit
create commands to all update scripts for objects added to the
public schema. This change will make update scripts fail if a
function with identical signature already exists when installing
or upgrading instead reusing the existing object.
From PG12 on, CREATE OR REPLACE is supported for aggregates,
therefore, since we have dropped support for PG11, we can avoid
going through the rigamarole of having our aggregates in a separate
file from the functions we define to support them. Nor do we need to
handle aggregates separately from other functions as their creation
is now idempotent.
We've decided to adopt the ts_ prefix on all exported C functions in
order to avoid having symbol conflicts with future postgres functions.
We've already started using this prefix on new functions and this commit
adds the prefix to to the old functions.
There is no CREATE OR REPLACE AGGREGATE which means that the only way to replace
an aggregate is to DROP then CREATE which is problematic as it will fail
if the previous version of the aggregate has dependencies.
This commit makes sure aggregates are not dropped and recreated every time.
NOTE that WHEN CREATING NEW FUNCTIONS in sql/aggregates.sql you should also make
sure they are created in an update script so that both new users and people
updating from a previous version get the new function.
sql/aggregates.sql is run only once when TimescaleDB is installed and is not
rerun during updates that is why everything created there should also be in an
update file.
Fixes#612
This PR adds the ability to have multiple different versions of the timescaledb
extension be used by different databases in the same PostgreSQL
instance (server).
This is accomplished by splitting this extension into two .so files.
1) timescaledb.so -- stuff under loader/. Really not a lot of code.
This code MUST be backwards compatible in the future.
2) timescaledb-version.so (most of our code). Need
not be backwards compatible.
Timescaledb.so becomes a small stub which is preloaded and whose main
reason for existing is to dynamically load the right
timescaledb-version.so when the time comes.
This change allows either of the above .so to be loaded in
shared_preload_libraries. But timescaledb.so allows for multiple
versions used on different databases in the same instance along
with smoother upgrades. Using timescaledb-version.so allows for
finer-grained control and lock-in and is appropriate in only a few
production environments.
This PR also adds version checking so that a clear failure message
will be displayed if the .so version does not match the SQL extension
version.
To support multi-version functionality we changed the way SQL update
scripts are generated. Previously, the system used a bunch of
intermediate upgrade scripts. So with 3 versions, you would have an
update script of 1--2, 2--3. But, this PR changes things so that we
produce direct "shortcut" update files: 1--3, 2--3.
This is done for 2 reasons:
1) Each of the update files should point to
$libdir/timescaledb-current_version. Since you cannot guarantee that
Previous .so for each intermediate version has been installed.
2) You don't want intermediate version updates installed without the
.so. For example, if you have versions 1,2,3
and you are installing version 3, you want the upgrade files 1--3,
2--3 but not 1--2 because if you have 1--2
then a user could do ALTER EXTENSION timescaledb UPDATE TO 2. But
the .so for version 2 may not be installed.
In order to test this functionality, we add a mock extension version .so
that we can test extension loading inside the regression framework.
Functions marked IMMUTABLE should also be parallel safe, but
aren't by default. This change marks all immutable functions
as parallel safe and removes the IMMUTABLE definitions on
some functions that have been wrongly labeled as IMMUTABLE.
If functions that are IMMUTABLE does not have the PARALLEL SAFE
label, then some standard PostgreSQL regression tests will fail
(this is true for PostgreSQL >= 10).
Aggregate functions that have serialize and deserialize support
functions (histogram, last, first, etc.) should have these
support functions marked STRICT.
PostgreSQL's regular test suite will fail when the timescaledb
module is loaded without these functions being marked STRICT.
