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.
Users can now (optionally) set a target chunk size and TimescaleDB
will try to adapt the interval length of the first open ("time")
dimension in order to reach that target chunk size. If a hypertable
has more than one open dimension, only the first one will have a
dynamically adapting interval.
Users can optionally specify their own function that calculates the
new dimension interval. They can also set a target size of 0 in order
to estimate a suitable target size for a chunk based on available
memory.
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.
This change is part of an effort to create a consistent way
of dealing with metadata catalog updates, which is currently
a mix of C API and INSERT/UPDATE/DELETE statements from SQL
code. This mix makes catalog handling unnecessarily complex as
there are multiple ways to update metadata, increasing the risk
of security issues with publically exposed SQL functions. It also
complicates things like cache invalidation, requiring different
mechanisms for C and SQL code. Catalog updates from SQL code
require triggers on metadata tables for cache invalidation that
do not work with native catalog updates.
The creation of chunks has been particularly messy in this regard,
making the code hard to follow. Especially the handling of a chunk's
constraints, where dimensional and other constraints were handled
differently. With this change, constraint handling is now consistent
across constraint types with a single API for updating metadata.
Reduce memory usage for out-of-order inserts
The chunk_result_relation_info should be put on the chunk memory
context. This will cause the rri constraint expr to also go onto
that context and be correctly freed when the chunk insert state
is destroyed.
This change refactors the chunk index handling to make better use
of standard PostgreSQL catalog information, while removing the
hypertable_index metadata table and associated triggers, including
those on the chunk_index table. The chunk_index table itself is
also simplified.
A benefit of this refactoring is that indexes are no longer
created using string mangling to construct the CREATE INDEX command
for a chunk, based on the string definition of the hypertable
index. Instead, indexes are created in C using proper index-related
internal data structures.
Chunk indexes can now also be renamed and are added in the parent
index tablespace. Changing tablespace on a hypertable index also
recurses to chunks, as expected. Default indexes that are added when
creating a hypertable use the hypertable's tablespace.
Creating Hypertable indexes with the CONCURRENTLY modifier is
currently blocked, due to unclear semantics regarding concurrent
creation over many tables, including how to deal with snapshots.
The update test script compares a TimescaleDB instance, which is
updated to the latest version from an older version, to a cleanly
installed one at the latest version. It does this by inserting the
same data on both and comparing the data and metadata tables. This
comparison breaks if the new version has changed some behavior (e.g.,
chunk indexes might use a different naming scheme), because the
updated version will retain the metadata related to the old behavior
while the latest version will create metadata according to the new
behavior.
To fix this issue, the update script now performs a database backup on
the old version and restores it on the cleanly installed version of
TimescaleDB. This retains the metadata in accordance with the old
behavior, although the new version will create new metadata according
to the new behavior. This has the further benefit of testing the
restore process during upgrades, which is probably the way people will
move to a new version of TimescaleDB if they do not update the
extension with the data in place.
The capture errors related to broken update scripts, the update test
now includes an integrity test for some metadata tables.
Applying triggers to chunks requires taking the definition
of a trigger on a hypertable and executing it on a chunk. Previously
this was done with string replacement in the trigger definition.
This was not especially safe, and thus we moved the logic to C
where we can do proper parsing/deparsing and replacement of the table
name. Another positive aspect is that we got rid of some DDL triggers.
Streamline code and remove triggers from chunk and
chunk_constraint. Lots of additional cleanup. Also removes need to CASCADE
hypertable drops (fixes#88).
This PR add support for primary-key, foreign-key, unique, and exclusion constraints.
Previously supported are CHECK and NOT NULL constraints. Now, foreign key
constraints where a hypertable references a plain table is support
(while vice versa, with a plain table references a hypertable, is still not).
When new chunks are created, the calculated chunk hypercube might
collide or not align with existing chunks when partitioning has
changed in one or more dimensions. In such cases, the chunk should be
cut to fit the alignment criteria and any collisions should be
resolved. Unfortunately, alignment and collision detection wasn't
properly handled.
This refactoring adds proper axis-aligned bounding box collision
detection generalized to N dimensions. It also correctly handles
dimension alignment.
Previously dimension_slice would only allow ranges to start and
end with values >= 0. However, this did not allow for timestamps
prior to 1970 because those times would be represented by negative
integers. With this PR we now support dates prior to 1970.
Addresses issue #153.
This adds support for all types of triggers on a hypertable except
INSERT AFTER. UPDATE and DELETE ROW triggers are automatically copied from
a hypertable onto the chunks. Therefore, any trigger defined on the
parent hypertable will apply to any row in any of the chunks as well.
STATEMENT level triggers and iNSERT triggers need not be copied in this
way.
It is not an error for range_end of a new chunk to be equal to
range_start of an existing chunk because range_end is exclusive.
Fix logic not to throw an error in that case.
Previously, catalog tables were not fully protected from malicious
non-superusers. This PR fixes permission handling be severely
restricting permissions to the catalog and instead using SECURITY
DEFINER functions to alter the catalog when needed without giving
users permission to do those same operations outside of these functions.
In addition, these functions check for proper permissions themselves
so are safe to use.
This PR also makes sure that chunk tables have the same owner as the
hypertable and correctly handles `ALTER TABLE...OWNER TO` commands to
keep this info in sync.
Tablespaces can now be associated with a hypertable
using the new user-facing API attach_tablespace().
Alternatively, if the main table, which is to be
converted into a hypertable, was created with an
associated tablespace, that tablespace will
automatically be associated also with the hypertable.
Whenever a chunk is created, a tablespace will be
chosen from the ones associated with the chunk's
hypertable (if any). This is done in a way that ensures
consistency in one dimension. I.e., if a hypertable
has a closed (space) dimension with a fixed number
of slices (ranges), it will ensure that chunks that
fall in the same slice will alsp be stored in the same
tablespace.
If a hypertable has more than one closed dimension,
the first one will be used to assign tablespaces
to chunks. If the table has no closed dimensions, but
one or more open (time) dimensions, then the first
time dimension will be used. However, since open
dimensions do not have a fixed number of slices,
tablespaces will be assigned in a round-robbin
fashion as new slices are created. Still, chunks
in the same time slice will be stored in the same
tablespace.
Previously, chunks could end up unaligned betweeen partitions if the chunk_time_interval
was updated between chunk creations. Now there is a check when a chunk is created whether there is
a chunk matching the time point in another partition and if there is, the new chunk is created
with the same interval.
Clean up the table schema to get rid of legacy tables and functionality
that makes it more difficult to provide an upgrade path.
Notable changes:
* Get rid of legacy tables and code
* Simplify directory structure for SQL code
* Simplify table hierarchy: remove root table and make chunk tables
* inherit directly from main table
* Change chunk table suffix from _data to _chunk
* Simplify schema usage: _timescaledb_internal for internal functions.
* _timescaledb_catalog for metadata tables.
* Remove postgres_fdw dependency
* Improve code comments in sql code
