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commit 88b3d6beac44ce6e265f4661bf6bcb8adaccbf12 Author: m-sanjana19 <[email protected]> AuthorDate: Mon Jul 29 20:49:29 2024 +0530 IMPALA-13071: Update the doc of Impala components Change-Id: I83192110d29c4d44529d1276a17c9da4a91435aa Reviewed-on: http://gerrit.cloudera.org:8080/21621 Tested-by: Impala Public Jenkins <[email protected]> Reviewed-by: Quanlong Huang <[email protected]> --- docs/topics/impala_components.xml | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) diff --git a/docs/topics/impala_components.xml b/docs/topics/impala_components.xml index cb70eb84f..6ce2ebe87 100644 --- a/docs/topics/impala_components.xml +++ b/docs/topics/impala_components.xml @@ -141,20 +141,25 @@ under the License. <conbody> - <p> The Impala component known as the Catalog Service relays the metadata - changes from Impala SQL statements to all the Impala daemons in a - cluster. It is physically represented by a daemon process named - <codeph>catalogd</codeph>. You only need such a process on one host in - a cluster. Because the requests are passed through the StateStore - daemon, it makes sense to run the <cmdname>statestored</cmdname> and - <cmdname>catalogd</cmdname> services on the same host. </p> - - <p> The catalog service avoids the need to issue <codeph>REFRESH</codeph> - and <codeph>INVALIDATE METADATA</codeph> statements when the metadata - changes are performed by statements issued through Impala. When you - create a table, load data, and so on through Hive, you do need to issue - <codeph>REFRESH</codeph> or <codeph>INVALIDATE METADATA</codeph> on an - Impala daemon before executing a query there. </p> + <p> The Impala component known as the Catalog Service relays the metadata changes from Impala + SQL statements to all the Impala coordinators in a cluster. It is physically represented by + a daemon process named <codeph>catalogd</codeph>. You only need such a process on one host + in a cluster. Because the requests are passed through the StateStore daemon, it makes sense + to run the <cmdname>statestored</cmdname> and <cmdname>catalogd</cmdname> services on the + same host. </p> + + <p> The catalog service avoids the need to issue <codeph>REFRESH</codeph> and + <codeph>INVALIDATE METADATA</codeph> statements when the metadata changes are performed by + statements issued through Impala. + </p> + <p> When you create a table, load data, and so on through Hive, you do need to issue + <codeph>REFRESH</codeph> or <codeph>INVALIDATE METADATA</codeph> on an Impala daemon + before executing a query. Performing <codeph>REFRESH</codeph> or <codeph>INVALIDATE + METADATA</codeph> is not required when <cite>Automatic Invalidation/Refresh of + Metadata</cite> is enabled. See <xref href="impala_metadata.xml#impala_metadata">Automatic + Invalidation/Refresh of Metadata</xref> also known as the Hive Metastore (HMS) event + processor.<note id="note_eyx_qcp_fcc" type="note">From Impala 4.1, Automatic + Invalidation/Refresh of Metadata is enabled by default.</note></p> <p> This feature touches a number of aspects of Impala:
