This change adds DDL support for HDFS caching. The DDL allows the user to indicate a
table or partition should be cached and which pool to cache the data into:
* Create a cached table: CREATE TABLE ... CACHED IN 'poolName'
* Cache a table/partition: ALTER TABLE ... [partitionSpec] SET CACHED IN 'poolName'
* Uncache a table/partition: ALTER TABLE ... [partitionSpec] SET UNCACHED
When a table/partition is marked as cached, a new HDFS caching request is submitted
to cache the location (HDFS path) of the table/partition and the ID of that request
is stored with in the table metadata (in the table properties). This is stored as:
'cache_directive_id'='<requestId>'. The cache requests and IDs are managed by HDFS
and persisted across HDFS restarts.
When a cached table or partition is dropped it is important to uncache the cached data
(drop the associated cache request). For partitioned tables, this means dropping all
cache requests from all cached partitions in the table.
Likewise, if a partitioned table is created as cached, new partitions should be marked
as cached by default.
It is desirable to know which cache pools exists early on (in analysis) so the query
will fail without hitting HDFS/CatalogServer if a non-existent pool is specified. To
support this, a new cache pool catalog object type was introduced. The catalog server
caches the known pools (periodically refreshing the cache) and sends the known pools out
in catalog updates. This allows impalads to perform analysis checks on cache pool
existence going to HDFS. It would be easy to use this to add basic cache pool management
in the future (ADD/DROP/SHOW CACHE POOL).
Waiting for the table/partition to become cached may take a long time. Instead of
blocking the user from access the time during this period we will wait for the cache
requests to complete in the background and once they have finished the table metadata
will be automatically refreshed.
Change-Id: I1de9c6e25b2a3bdc09edebda5510206eda3dd89b
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2310
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: jenkins
Avro tables that were not created with a column-definition list do not have
their columns properly populated in the Metastore backend DB (HIVE-6308).
For such tables COMPUTE STATS and Hive's ANALYZE TABLE cannot succeed.
This patch fails COMPUTE STATS in analysis for such broken Avro tables
and adds tests for Avro tables with mismatched a column-definition list
and Avro schema.
Change-Id: I561ecea944ae2f83d69950b7a1ab9edaa89bdcea
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1892
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1920
The parquet file stores the application version that wrote it so
is different between our c4 and c5 branches.
HBase storage is also not guaranteed to be identical across versions.
Change-Id: I02984a55e0678756e50c1fff6db22c43788d3916
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1028
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins
A compute stats command computes the table and column stats for a given
table and persists them in the metastore.
The table stats consist of the per-partition and per-table row count.
The column stats are computed on a per-table basis and consist of the
number of distinct values and the number of NULLs per column.
This patch introduces a new 'child query' concept that
compute stats utilizes. Child queries are cancelled
if the parent query is cancelled. A compute stats stmt is
executed by the following query hirarchy:
parent: compute stats query (DDL)
- child: compute table stats query (QUERY)
- child: compute column stats query (QUERY)
The new child query concept is necessary to decouple child query fetches
from parent query fetches, i.e., we could not execute a child query as
part of the original compute stats query, because then a client could
fetch the results we need for updating the Metastore statistics. The
reason why our existing CTAS works without this decoupling
is that its insert 'child query' is not fetchable.
Change-Id: I560533e3cb09bcbbdb3eea7fcf0b460bc6b36dcd
Reviewed-on: http://gerrit.ent.cloudera.com:8080/873
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins
