So far we've reloaded them frequently. Besides avoiding that cost -
noticeable for some workloads with large shard counts - it makes it
easier to add information to ShardPlacements that help us make
placement_connection.c colocation aware.
With this change, we start to replicate all reference tables to the new node when new node
is added to the cluster with master_add_node command. We also update replication factor
of reference table's colocation group.
With this change we introduce new UDF, upgrade_to_reference_table, which can be used to
upgrade existing broadcast tables reference tables. For upgrading, we require that given
table contains only one shard.
Added a new UDF, mark_tables_colocated(), to colocate tables with the same
configuration (shard count, shard replication count and distribution column type).
Adds support for PostgreSQL 9.6 by copying in the requisite ruleutils
file and refactoring the out/readfuncs code to flexibly support the
old-style copy/pasted out/readfuncs (prior to 9.6) or use extensible
node APIs (in 9.6 and higher).
Most version-specific code within this change is only needed to set new
fields in the AggRef nodes we build for aggregations. Version-specific
test output files were added in certain cases, though in most they were
not necessary. Each such file begins by e.g. printing the major version
in order to clarify its purpose.
The comment atop citus_nodes.h details how to add support for new nodes
for when that becomes necessary.
This change adds the required infrastructure about metadata snapshot from MX
codebase into Citus, mainly metadata_sync.c file and master_metadata_snapshot UDF.
So far placements were assigned an Oid, but that was just used to track
insertion order. It also did so incompletely, as it was not preserved
across changes of the shard state. The behaviour around oid wraparound
was also not entirely as intended.
The newly introduced, explicitly assigned, IDs are preserved across
shard-state changes.
The prime goal of this change is not to improve ordering of task
assignment policies, but to make it easier to reference shards. The
newly introduced UpdateShardPlacementState() makes use of that, and so
will the in-progress connection and transaction management changes.
Related to #786
This change adds the `pg_dist_node` table that contains the information
about the workers in the cluster, replacing the previously used
`pg_worker_list.conf` file (or the one specified with `citus.worker_list_file`).
Upon update, `pg_worker_list.conf` file is read and `pg_dist_node` table is
populated with the file's content. After that, `pg_worker_list.conf` file
is renamed to `pg_worker_list.conf.obsolete`
For adding and removing nodes, the change also includes two new UDFs:
`master_add_node` and `master_remove_node`, which require superuser
permissions.
'citus.worker_list_file' guc is kept for update purposes but not used after the
update is finished.
Before this change, we do not check whether given table which already contains any data
in master_create_distributed_table command. If that table contains any data, making it
it distributed, makes that data hidden to user. With this change, we now gave error to
user if the table contains data.
That's important because ownership of relations implies special
privileges. Without this change, a distributed table can be accessible
by a table's owner, but a shard created by another user might not.
Previously several commands, amongst them commands like
master_create_distributed_table(), were allowed for everyone. That's not
good: Even though citus currently requires superuser permissions, we
shouldn't allow non-superusers to perform actions as sensitive as making
a table distributed.
There's no checks on the worker_* functions, as these usually just punt
the action to underlying postgres functionality, which then perform the
necessary checks.
This macro is intended to receive a bare integer literal (no suffix).
It adds a suffix as necessary, depending upon available features. On
e.g. 32-bit platforms, the existing code failed to compile because a
suffix was added to the existing suffix. This fixes that problem.
Andres Freund
Burak Yucesoy
Eren Basak
Metin Doslu
Brian Cloutier
Robin Thomas
Murat Tuncer
Jason Petersen
Onder Kalaci