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From:Hendrik Woltersdorf Date:March 5 2018 9:44am
Subject:Antwort: Re: Out of operation records in local data manager far below
MaxNoOfConcurrentOperations
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Hi Mauritz,

the table(s), where I see this error often, have:

1) a primary key index --> thats +1
2) no blobs
3) 4) no foreign keys
5) the primary key is one integer column
6) the number of ldm threads should be 6 (MaxNoOfExecutionThreads=12) and
ndb_desc shows 12 partitions on two datanodes in one node group

We did not set MaxNoOfLocalOperations explicitely.

regards,
Hendrik Woltersdorf

FinTech Group AG
Peter-Breuer-Str. 13
08056 Zwickau
hendrik.woltersdorf@stripped
www.fintechgroup.com


FinTech Group AG, Frankfurt am Main - HRB Frankfurt 103516 - Gerichtsstand
Frankfurt am Main - Vorstand: Frank Niehage (Vors.), Muhamad Said Chahrour
- Aufsichtsratsvorsitzender: Martin Korbmacher - www.fintechgroup.com
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Von:	Mauritz Sundell <mauritz.sundell@stripped>
An:	Hendrik Woltersdorf <hendrik.woltersdorf@stripped>,
            cluster@stripped
Datum:	05.03.2018 10:24
Betreff:	Re: Out of operation records in local data manager far below
            MaxNoOfConcurrentOperations



Hi Hendrik

On 2018-03-05 09:03, Hendrik Woltersdorf wrote:
> Hi,
>
> we run a MySQL-Cluster, currently version 7.4.15, where we get "Out of
> operation records in local data manager" at approximately 55000 rows
> updated or deleted in one transaction,
> even though MaxNoOfConcurrentOperations=300000.
>
> Any ideas, why 300000 operation records are not enough for 55000 rows?
Assuming there are no other concurrent transactions, this could be due
to extra implied load such as:

1) changes to unique indexes, each change takes an operation.

2) changes to blob columns, each change column can take one or more
operation depending  on size of value.

3) foreign keys causing lookups in parent table

4) foreign keys cascading into child tables

Or it could be due to skew load due to:

5) Partial primary key used as partitioning key.

6) The number of partitions do not match number of LDM-threads.
     This should typically not happen unless explicitly expressed, or if
one have reconfigured cluster with more LDM-threads or adding nodes
without runnning reorganize partitions.

One can also configure the number of operations records in local data
manager (LDM) with MaxNoOfLocalOperations.
By default that is slightly bigger than MaxNoOfConcurrentOperation.

Mauritz


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Thread
Out of operation records in local data manager far belowMaxNoOfConcurrentOperationsHendrik Woltersdorf5 Mar
  • Re: Out of operation records in local data manager far belowMaxNoOfConcurrentOperationsMauritz Sundell5 Mar
    • Antwort: Re: Out of operation records in local data manager far belowMaxNoOfConcurrentOperationsHendrik Woltersdorf5 Mar
      • Re: Antwort: Re: Out of operation records in local data manager farbelow MaxNoOfConcurrentOperationsMauritz Sundell5 Mar
        • Re: Antwort: Re: Out of operation records in local data manager farbelow MaxNoOfConcurrentOperationsMauritz Sundell5 Mar
    • Re: Out of operation records in local data manager far below MaxNoOfConcurrentOperationsTom Egan5 Mar
      • Antwort: Re: Out of operation records in local data manager far belowMaxNoOfConcurrentOperationsHendrik Woltersdorf5 Mar