Alex Behm has uploaded this change for review. (
http://gerrit.cloudera.org:8080/8136
Change subject: IMPALA-5310: Add COMPUTE STATS TABLESAMPLE.
......................................................................
IMPALA-5310: Add COMPUTE STATS TABLESAMPLE.
Adds the TABLESAMPLE clause for COMPUTE STATS.
Syntax:
COMPUTE STATS <table> TABLESAMPLE SYSTEM(<number>) [REPEATABLE(<number>)]
Computes and replaces the table-level row count and total file size,
as well as all table-level column statistics. Existing partition-level
row counts are not modified.
The TABLESAMPLE clause can be used to limit the scanned data volume to
a desired percentage. When sampling, the unmodified results of the
COMPUTE STATS queries are sent to the CatalogServer. There, the stats
are extrapolated before storing them into the HMS so as not to confuse
other engines like Hive/SparkSQL which may rely on the shared HMS
fields being accurate.
Limitations
- TABLESAMPLE requires --enable_stats_extrapolation=true
- TABLESAMPLE is not supported for COMPUTE INCREMENTAL STATS
Changes to EXPLAIN
The stored statistics from the HMS are more clearly displayed under
a 'stored statistics' section. Example:
00:SCAN HDFS [functional.alltypes, RANDOM]
partitions=24/24 files=24 size=478.45KB
stored statistics:
table: rows=7300 size=478.45KB
partitions: 24/24 rows=7300
columns: all
Testing:
- added new functional tests
- core/hdfs run passed
Change-Id: I7f3e72471ac563adada4a4156033a85852b7c8b7
---
M be/src/exec/catalog-op-executor.cc
M common/thrift/JniCatalog.thrift
M fe/src/main/cup/sql-parser.cup
M fe/src/main/java/org/apache/impala/analysis/ComputeStatsStmt.java
M fe/src/main/java/org/apache/impala/analysis/TableSampleClause.java
M fe/src/main/java/org/apache/impala/catalog/ColumnStats.java
M fe/src/main/java/org/apache/impala/catalog/HdfsTable.java
M fe/src/main/java/org/apache/impala/planner/DataSourceScanNode.java
M fe/src/main/java/org/apache/impala/planner/HBaseScanNode.java
M fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java
M fe/src/main/java/org/apache/impala/planner/ScanNode.java
M fe/src/main/java/org/apache/impala/service/CatalogOpExecutor.java
M fe/src/test/java/org/apache/impala/analysis/AnalyzeDDLTest.java
M fe/src/test/java/org/apache/impala/analysis/ParserTest.java
M fe/src/test/java/org/apache/impala/hive/executor/UdfExecutorTest.java
M
testdata/workloads/functional-planner/queries/PlannerTest/constant-folding.test
M
testdata/workloads/functional-planner/queries/PlannerTest/fk-pk-join-detection.test
M testdata/workloads/functional-planner/queries/PlannerTest/max-row-size.test
M
testdata/workloads/functional-planner/queries/PlannerTest/mt-dop-validation.test
M
testdata/workloads/functional-planner/queries/PlannerTest/parquet-filtering.test
M
testdata/workloads/functional-planner/queries/PlannerTest/partition-pruning.test
M
testdata/workloads/functional-planner/queries/PlannerTest/resource-requirements.test
M
testdata/workloads/functional-planner/queries/PlannerTest/sort-expr-materialization.test
M
testdata/workloads/functional-planner/queries/PlannerTest/spillable-buffer-sizing.test
M testdata/workloads/functional-planner/queries/PlannerTest/tablesample.test
M
testdata/workloads/functional-query/queries/QueryTest/alter-table-set-column-stats.test
M
testdata/workloads/functional-query/queries/QueryTest/compute-stats-incremental.test
A
testdata/workloads/functional-query/queries/QueryTest/compute-stats-tablesample.test
M testdata/workloads/functional-query/queries/QueryTest/compute-stats.test
M testdata/workloads/functional-query/queries/QueryTest/explain-level2.test
M testdata/workloads/functional-query/queries/QueryTest/explain-level3.test
M
testdata/workloads/functional-query/queries/QueryTest/hbase-compute-stats-incremental.test
M testdata/workloads/functional-query/queries/QueryTest/hbase-compute-stats.test
M testdata/workloads/functional-query/queries/QueryTest/show-stats.test
M testdata/workloads/functional-query/queries/QueryTest/stats-extrapolation.test
M testdata/workloads/functional-query/queries/QueryTest/truncate-table.test
M tests/custom_cluster/test_stats_extrapolation.py
M tests/metadata/test_explain.py
38 files changed, 1,882 insertions(+), 1,193 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/36/8136/1
--
To view, visit http://gerrit.cloudera.org:8080/8136
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I7f3e72471ac563adada4a4156033a85852b7c8b7
Gerrit-Change-Number: 8136
Gerrit-PatchSet: 1
Gerrit-Owner: Alex Behm <alex.b...@cloudera.com>
