question Re: "invalidate metadata" do not work in Support Questions

"invalidate metadata" do not work

smt78100 — Fri, 16 Sep 2022 10:45:25 GMT

Hello there,

I'm new to Hadoop and I'm currently trying some examples resembling to the problem I have to solve.

I've created a very simple table in Hive (via hive shell). Then tried to look at it in Impala (via impala-shell).
Even though I typed "invalidate metadata" before looking at the table in Impala, I couldn't see the table created in Hive.

It seems that Impala and/or Hive cannot access the meta-store (?).
I looked at impalad logs but didn't find any error.

Below my configuration and the stuff I typed in hive and impala.

1.Configuration

* A 6 node CentOS 6.8 cluster
* CDH 5.7.1

* impalad version 2.5.0
* Impala Shell v2.5.0
* Apache Derby - 10.11.1.1
* Hive 1.1.0

2. Table creation & lookup

hive> create database new_db_from_hive ;

hive> create table new_db_from_hive.new_table_from_hive(x int) ;

hive> show databases like 'new*' ;

new_db_from_hive

Then in Impala :

[myhost.hadoop:21000] > invalidate metadata ;

Query: invalidate metadata

Fetched 0 row(s) in 3.26s

[myhost.hadoop:21000] > show databases ;

Query: show databases

+------------------+----------------------------------------------+

| name | comment |

+------------------+----------------------------------------------+

| _impala_builtins | System database for Impala builtin functions |

| default | Default Hive database |

+------------------+----------------------------------------------+

However, I can see the database on the hdfs file system :

$ hdfs dfs -ls /user/hive/warehouse/new_db_from_hive.db

Found 1 items

drwxrwxrwt - <myuserid> hive 0 2016-10-24 18:46 /user/hive/warehouse/new_db_from_hive.db/new_table_from_hive

I don't know what is missing.
Thank you in advance for any help.

Re: "invalidate metadata" do not work

jbapple — Mon, 24 Oct 2016 17:32:52 GMT

What do you see if you type "use new_db_from_hive;" into your Impala shell?

Re: "invalidate metadata" do not work

smt78100 — Mon, 24 Oct 2016 18:28:53 GMT

It gives me an arror :

> use new_db_from_hive ;

Query: use new_db_from_hive

ERROR: AnalysisException: Database does not exist: new_db_from_hive

Re: "invalidate metadata" do not work

Dimitris — Mon, 24 Oct 2016 19:33:49 GMT

Does it work if you create the database through Impala?

Re: "invalidate metadata" do not work

smt78100 — Mon, 24 Oct 2016 20:09:39 GMT

Yes. Databases and Tables can be created normally in Impala.

[myhost.hadoop:21000] > create database new_db_from_impala ;

Query: create database new_db_from_impala

Fetched 0 row(s) in 0.18s

[myhost.hadoop:21000] > create table new_db_from_impala.new_table_from_impala(x int) ;

Query: create table new_db_from_impala.new_table_from_impala(x int)

[myhost.hadoop:21000] > show databases ;

Query: show databases

+--------------------+----------------------------------------------+

| name | comment |

+--------------------+----------------------------------------------+

| _impala_builtins | System database for Impala builtin functions |

| default | Default Hive database |

| new_db_from_impala | |

+--------------------+----------------------------------------------+

Fetched 3 row(s) in 0.00s

[myhost.hadoop:21000] > use new_db_from_impala ;

Query: use new_db_from_impala

[myhost.hadoop:21000] > show tables ;

Query: show tables

+-----------------------+

| name |

+-----------------------+

| new_table_from_impala |

+-----------------------+

Fetched 1 row(s) in 0.00s

Re: "invalidate metadata" do not work

Dimitris — Mon, 24 Oct 2016 20:24:46 GMT

The connection to HMS seems to be working fine. Here are some things to consider:

1. create a table in Hive and run invalidate metadata in Impala. Does this work?

2. Check the impalad.INFO and catalogd.INFO for any exceptions/errors

Dimitris

Re: "invalidate metadata" do not work

smt78100 — Mon, 24 Oct 2016 21:30:44 GMT

1. create a table in Hive and run invalidate metadata in Impala. Does this work?

This is what I've done several times (create table/database in Hive; then run invalidate metadata in Impala). And no. It doesn't work.

2. Check the impalad.INFO and catalogd.INFO for any exceptions/errors

catalogd.ERROR includes exceptions concerning the missing tables. But there's no additional information about the origin of the problem :

E1024 15:55:53.764930 10217 catalog-server.cc:76] TableNotFoundException: Table not found: new_db_from_hive.new_table_from_hive

E1024 15:59:52.447249 10217 catalog-server.cc:76] TableNotFoundException: Table not found: new_db_from_hive2nd.new_table_from_hive

E1024 16:18:37.696986 14116 catalog-server.cc:76] TableNotFoundException: Table not found: new_db_from_hive.new_table_from_hive

E1024 16:30:49.233502 10217 catalog-server.cc:76] TableNotFoundException: Table not found: new_db_from_hive3rd.new_table_from_hive

In impalad.INFO, I found some lines that *may* be of interest (?) :

I1024 18:50:41.929322 10036 Frontend.java:866] analyze query invalidate metadata

I1024 18:50:41.950764 10036 impala-server.cc:1430] Waiting for catalog version: 34 current version: 26

I1024 18:50:45.444826 10036 impala-beeswax-server.cc:307] get_results_metadata(): query_id=5243589279189211:df729a8d9a1687a4

I1024 18:50:45.445307 10036 impala-beeswax-server.cc:349] close(): query_id=5243589279189211:df729a8d9a1687a4

I1024 18:50:45.445310 10036 impala-server.cc:915] UnregisterQuery(): query_id=5243589279189211:df729a8d9a1687a4

I1024 18:50:45.445314 10036 impala-server.cc:1001] Cancel(): query_id=5243589279189211:df729a8d9a1687a4

I1024 18:50:45.446462 10036 impala-beeswax-server.cc:172] query(): query=invalidate metadata

I don't know if this variation of version in the catalog is normal.

3. Keep in mind that invalidate metadata is asynchronous, i.e. it returns immediately and then in the background the catalog objects are sent to the impalad nodes. This could take some time, so the question is if the db shows up eventually (after a few secs) or never.

There are few data in Hive, Impala.
And even if I try looking at the existing tables in Impala much later after I ran the "invalidate metadata" query, they still do not appear.

Re: "invalidate metadata" do not work

smt78100 — Mon, 24 Oct 2016 21:33:17 GMT