Add one more example
Project: http://git-wip-us.apache.org/repos/asf/trafodion/repo Commit: http://git-wip-us.apache.org/repos/asf/trafodion/commit/95a63605 Tree: http://git-wip-us.apache.org/repos/asf/trafodion/tree/95a63605 Diff: http://git-wip-us.apache.org/repos/asf/trafodion/diff/95a63605 Branch: refs/heads/master Commit: 95a63605a1eab978824ec23dd45ac4760f27defd Parents: ee527be Author: liu.yu <qwerty...@hotmail.com> Authored: Fri May 25 13:41:19 2018 +0800 Committer: liu.yu <qwerty...@hotmail.com> Committed: Fri May 25 13:41:19 2018 +0800 ---------------------------------------------------------------------- .../src/asciidoc/_chapters/sql_statements.adoc | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/trafodion/blob/95a63605/docs/sql_reference/src/asciidoc/_chapters/sql_statements.adoc ---------------------------------------------------------------------- diff --git a/docs/sql_reference/src/asciidoc/_chapters/sql_statements.adoc b/docs/sql_reference/src/asciidoc/_chapters/sql_statements.adoc index ed697ec..1d4095b 100644 --- a/docs/sql_reference/src/asciidoc/_chapters/sql_statements.adoc +++ b/docs/sql_reference/src/asciidoc/_chapters/sql_statements.adoc @@ -1491,8 +1491,8 @@ SQL>CONTROL QUERY DEFAULT PARALLEL_NUM_ESPS '2'; --- SQL operation complete. ``` - -* This example resets the `PARALLEL_NUM_ESPS` attribute to its system value in the current process. ++ +This example resets the `PARALLEL_NUM_ESPS` attribute to its system value in the current process. In this case, the compiler calculates the number of ESPs to be used. + ``` @@ -1501,6 +1501,14 @@ SQL>CONTROL QUERY DEFAULT PARALLEL_NUM_ESPS 'system'; --- SQL operation complete. ``` +* This example allows the optimizer to generate an execution using hash join. ++ +``` +SQL>CONTROL QUERY DEFAULT HASH_JOIN 'ON'; + +--- SQL operation complete. +``` + <<< [[create_function_statement]] == CREATE FUNCTION Statement @@ -6461,7 +6469,7 @@ The ON predicate must select a unique row if the MERGE has a _when-not-matched-c === Considerations for MERGE [[merge_upsert_using_single_row]] -=== Upsert Using Single Row +==== Upsert Using Single Row A MERGE statement allows you to specify a set of column values that should be updated if the row is found, and another row to be inserted if the row is not found. The ON predicate must select exactly one row that is to be updated if the
