Repository: incubator-hawq-docs Updated Branches: refs/heads/master ad9b06696 -> aaa7ebba5
analyze not supported on json, hbase external tables (closes #122) Project: http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/repo Commit: http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/commit/aaa7ebba Tree: http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/tree/aaa7ebba Diff: http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/diff/aaa7ebba Branch: refs/heads/master Commit: aaa7ebba5964dc0c53744a153da9cb164f08f765 Parents: ad9b066 Author: Lisa Owen <[email protected]> Authored: Wed May 31 09:12:02 2017 -0700 Committer: David Yozie <[email protected]> Committed: Wed May 31 09:12:02 2017 -0700 ---------------------------------------------------------------------- markdown/pxf/HBasePXF.html.md.erb | 2 ++ markdown/pxf/JsonPXF.html.md.erb | 1 + markdown/reference/sql/ANALYZE.html.md.erb | 6 ++++-- 3 files changed, 7 insertions(+), 2 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/blob/aaa7ebba/markdown/pxf/HBasePXF.html.md.erb ---------------------------------------------------------------------- diff --git a/markdown/pxf/HBasePXF.html.md.erb b/markdown/pxf/HBasePXF.html.md.erb index ddb86d5..90dacf3 100644 --- a/markdown/pxf/HBasePXF.html.md.erb +++ b/markdown/pxf/HBasePXF.html.md.erb @@ -53,6 +53,8 @@ The HBase profile is equivalent to the following PXF parameters: - Accessor=org.apache.hawq.pxf.plugins.hbase.HBaseAccessor - Resolver=org.apache.hawq.pxf.plugins.hbase.HBaseResolver +**Note**: `ANALYZE` operations are not supported on external tables you create with the `HBase` profile. + ## <a id="columnmapping"></a>Column Mapping Most HAWQ external tables (PXF or others) require that the HAWQ table attributes match the source data record layout, and include all the available attributes. With HAWQ, however, you use the PXF HBase plug-in to specify the subset of HBase qualifiers that define the HAWQ PXF table. To set up a clear mapping between each attribute in the PXF table and a specific qualifier in the HBase table, you can use either direct mapping or indirect mapping. In addition, the HBase row key is handled in a special way. http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/blob/aaa7ebba/markdown/pxf/JsonPXF.html.md.erb ---------------------------------------------------------------------- diff --git a/markdown/pxf/JsonPXF.html.md.erb b/markdown/pxf/JsonPXF.html.md.erb index 6aeea7e..e22a75c 100644 --- a/markdown/pxf/JsonPXF.html.md.erb +++ b/markdown/pxf/JsonPXF.html.md.erb @@ -176,6 +176,7 @@ JSON-plug-in-specific keywords and values used in the `CREATE EXTERNAL TABLE` ca | FORMAT | The `FORMAT` clause must specify `CUSTOM`. | | FORMATTER | The JSON `CUSTOM` format supports only the built-in `pxfwritable_import` `FORMATTER`. | +**Note**: `ANALYZE` operations are not supported on external tables you create with the `Json` profile. ### Example 1 <a id="jsonexample1"></a> http://git-wip-us.apache.org/repos/asf/incubator-hawq-docs/blob/aaa7ebba/markdown/reference/sql/ANALYZE.html.md.erb ---------------------------------------------------------------------- diff --git a/markdown/reference/sql/ANALYZE.html.md.erb b/markdown/reference/sql/ANALYZE.html.md.erb index eb0af77..98fadd8 100644 --- a/markdown/reference/sql/ANALYZE.html.md.erb +++ b/markdown/reference/sql/ANALYZE.html.md.erb @@ -67,14 +67,16 @@ For large tables, `ANALYZE` takes a random sample of the table contents, rather The largest statistics target among the columns being analyzed determines the number of table rows sampled to prepare the statistics. Increasing the target causes a proportional increase in the time and space needed to do `ANALYZE`. -The `pxf_enable_stat_collection` server configuration parameter determines if `ANALYZE` calculates statistics for PXF readable tables. When `pxf_enable_stat_collection` is true, the default setting, `ANALYZE` estimates the number of tuples in the table from the total size of the table, the size of the first fragment, and the number of tuples in the first fragment. Then it builds a sample table and calculates statistics for the PXF table by running statistics queries on the sample table, the same as it does with native tables. A sample table is always created to calculate PXF table statistics, even when the table has a small number of rows. +The `pxf_enable_stat_collection` server configuration parameter determines if `ANALYZE` calculates statistics for PXF readable external tables. When `pxf_enable_stat_collection` is true, the default setting, `ANALYZE` estimates the number of tuples in the table from the total size of the table, the size of the first fragment, and the number of tuples in the first fragment. Then it builds a sample table and calculates statistics for the PXF table by running statistics queries on the sample table, the same as it does with native tables. A sample table is always created to calculate PXF table statistics, even when the table has a small number of rows. The `pxf_stat_max_fragments` configuration parameter, default 100, sets the maximum number of fragments that are sampled to build the sample table. Setting `pxf_stat_max_fragments` to a higher value provides a more uniform sample, but decreases `ANALYZE` performance. Setting it to a lower value increases performance, but the statistics are calculated on a less uniform sample. -When `pxf_stat_max_fragments` is false, `ANALYZE` outputs a message to warn that it is skipping the PXF table because `pxf_stat_max_fragments` is turned off. +When `pxf_stat_max_fragments` is false, `ANALYZE` outputs a message to warn that it is skipping the analyze operation on the PXF table because `pxf_stat_max_fragments` is turned off. There may be situations where the remote statistics retrieval could fail to perform a task on a PXF table. For example, if a PXF Java component is down, the remote statistics retrieval might not occur, and the database transaction would not succeed. In these cases, the statistics remain with the default external table values. +**Note**: `ANALYZE` operations are not supported on PXF external tables created with the `HBase` or `Json` profiles. + ## <a id="examples"></a>Examples Collect statistics for the table `mytable`:
