[CARBONDATA-2783][BloomDataMap][Doc] Update document for bloom filter datamap
add example for enable/disable datamap This closes #2554 Project: http://git-wip-us.apache.org/repos/asf/carbondata/repo Commit: http://git-wip-us.apache.org/repos/asf/carbondata/commit/d691d49d Tree: http://git-wip-us.apache.org/repos/asf/carbondata/tree/d691d49d Diff: http://git-wip-us.apache.org/repos/asf/carbondata/diff/d691d49d Branch: refs/heads/branch-1.4 Commit: d691d49d4fb5924269f620cd68c7ccb84b95a806 Parents: 0a6fe08 Author: Manhua <[email protected]> Authored: Wed Jul 25 16:51:49 2018 +0800 Committer: ravipesala <[email protected]> Committed: Tue Jul 31 00:11:26 2018 +0530 ---------------------------------------------------------------------- docs/datamap/bloomfilter-datamap-guide.md | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/carbondata/blob/d691d49d/docs/datamap/bloomfilter-datamap-guide.md ---------------------------------------------------------------------- diff --git a/docs/datamap/bloomfilter-datamap-guide.md b/docs/datamap/bloomfilter-datamap-guide.md index 0fb3ba2..325a508 100644 --- a/docs/datamap/bloomfilter-datamap-guide.md +++ b/docs/datamap/bloomfilter-datamap-guide.md @@ -26,7 +26,16 @@ Showing all DataMaps on this table SHOW DATAMAP ON TABLE main_table ``` -It will show all DataMaps created on main table. + +Disable Datamap +> The datamap by default is enabled. To support tuning on query, we can disable a specific datamap during query to observe whether we can gain performance enhancement from it. This will only take effect current session. + + ``` + // disable the datamap + SET carbon.datamap.visible.dbName.tableName.dataMapName = false + // enable the datamap + SET carbon.datamap.visible.dbName.tableName.dataMapName = true + ``` ## BloomFilter DataMap Introduction
