* Introduce 3 partitioned size udfs
* Add tests for new partition size udfs
* Fix type incompatibilities
* Convert UDFs into pure sql functions
* Fix function comment
* Reimplement citus_update_table_statistics
* Update stats for the given table not colocation group
* Add tests for reimplemented citus_update_table_statistics
* Use coordinated transaction, merge with citus_shard_sizes functions
* Update the old master_update_table_statistics as well
With citus shard helper view, we can easily see:
- where each shard is, which node, which port
- what kind of table it belongs to
- its size
With such a view, we can see shards that have a size bigger than some
value, which could be useful. Also debugging can be easier in production
as well with this view.
Fetch shards in one go per node
The previous implementation was slow because it would do a lot of round
trips, one per shard to be exact. Hence it is improved so that we fetch
all the shard_name, shard-size pairs per node in one go.
Construct shards_names, sizes query on coordinator
Citus has the logic to truncate the long shard names to prevent
various issues, including self-deadlocks. However, for partitioned
tables, when index is created on the parent table, the index names
on the partitions are auto-generated by Postgres. We use the same
Postgres function to generate the index names on the shards of the
partitions. If the length exceeds the limit, we switch to sequential
execution mode.
Introduce table entry utility functions
Citus table cache entry utilities are introduced so that we can easily
extend existing functionality with minimum changes, specifically changes
to these functions. For example IsNonDistributedTableCacheEntry can be
extended for citus local tables without the need to scan the whole
codebase and update each relevant part.
* Introduce utility functions to find the type of tables
A table type can be a reference table, a hash/range/append distributed
table. Utility methods are created so that we don't have to worry about
how a table is considered as a reference table etc. This also makes it
easy to extend the table types.
* Add IsCitusTableType utilities
* Rename IsCacheEntryCitusTableType -> IsCitusTableTypeCacheEntry
* Change citus table types in some checks
create_distributed_function(function_name,
distribution_arg_name,
colocate_with text)
This UDF did not allow colocate_with parameters when there were no
disttribution_arg_name supplied. This commit changes the behaviour to
allow missing distribution_arg_name parameters when the function should
be colocated with a reference table.
CMDTAG_SELECT exists in PG12 hence defining a MACRO such as
CMDTAG_SELECT -> "SELECT" is not possible. I chose CMDTAG_SELECT_COMPAT
because with the COMPAT suffix it is explicit that it maps to different
things in different versions and also has a less chance of mapping
something irrevelant. For example if we used SELECT as a macro, then it
would map every SELECT to whatever it is mapping to, which might have
unexpected/undesired behaviour.
With PG13 heap_* (heap_open, heap_close etc) are replaced with table_*
(table_open, table_close etc).
It is better to use the new table access methods in the codebase and
define the macros for the previous versions as we can easily remove the
macro without having to change the codebase when we drop the support for
the old version.
Commits that introduced this change on Postgres:
f25968c49697db673f6cd2a07b3f7626779f1827
e0c4ec07284db817e1f8d9adfb3fffc952252db0
4b21acf522d751ba5b6679df391d5121b6c4a35f
Command to see relevant commits on Postgres side:
git log --all --grep="heap_open"
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