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Posted to dev@hbase.apache.org by Vladimir Rodionov <vr...@carrieriq.com> on 2013/10/11 23:18:45 UTC
skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
>From HRegion:
synchronized(scannerReadPoints) {
if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
// This scan can read even uncommitted transactions
this.readPt = Long.MAX_VALUE;
MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
} else {
this.readPt = MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
}
If isolation level is READ_UNCOMMITTED than this method should never be called in both StoreFileScanner and MemStoreScanner
If isolation level is READ_COMMITTED than this method must be called only in MemStoreScanner, because HFiles are immutable no new KV's can be added
to HFile after StoreFileScanner was created.
Correct?
Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com
Confidentiality Notice: The information contained in this message, including any attachments hereto, may be confidential and is intended to be read only by the individual or entity to whom this message is addressed. If the reader of this message is not the intended recipient or an agent or designee of the intended recipient, please note that any review, use, disclosure or distribution of this message or its attachments, in any form, is strictly prohibited. If you have received this message in error, please immediately notify the sender and/or Notifications@carrieriq.com and delete or destroy any copy of this message and its attachments.
Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Posted by Vladimir Rodionov <vl...@gmail.com>.
Created https://issues.apache.org/jira/browse/HBASE-9751.
On Fri, Oct 11, 2013 at 8:55 PM, lars hofhansl <la...@apache.org> wrote:
> Taking a quick look... It is easy to reduce the ThreadLocal calls by 50%
> without any refactoring in the Memstore.
>
> Also thinking about this more, we already have metadata in HFile about the
> newest memstoreTS; I used that optimize storing the memstoreTS in HFiles
> away (HBASE-8166 and HBASE-8151).
>
> We could use this during scanning as well and avoid checking against the
> readpoint altogether.
> (might need some refactoring, though, have to checked closer).
>
>
> -- Lars
>
>
>
> ----- Original Message -----
> From: lars hofhansl <la...@apache.org>
> To: "dev@hbase.apache.org" <de...@hbase.apache.org>
> Cc:
> Sent: Friday, October 11, 2013 6:28 PM
> Subject: Re: skipKVsNewerThanReadpoint in StoreFileScanner and
> MemStoreScanner
>
> Interesting. Never came up in my profiling of raw scan performance.
> Of course my assumption was that the vast majority of all KVs are in
> HFiles and thus in the blockcache (not the memstore).
>
> ThreadLocals are indeed expensive, we ran into such problems as well (code
> unrelated to HBase, though).
>
>
> Mind filing a jira, Vladimir? If there's a perf issue, we should fix it.
>
>
> -- Lars
>
> ________________________________
>
> From: Vladimir Rodionov <vl...@gmail.com>
> To: "dev@hbase.apache.org" <de...@hbase.apache.org>
> Sent: Friday, October 11, 2013 2:36 PM
> Subject: Re: skipKVsNewerThanReadpoint in StoreFileScanner and
> MemStoreScanner
>
>
> Yes, threadLocal.get() is expensive when you count every nanosecond. There
> is no need to call it every time in MemStoreScanner.next().
>
>
>
> On Fri, Oct 11, 2013 at 2:32 PM, Ted Yu <yu...@gmail.com> wrote:
>
> > MultiVersionConsistencyControl.getThreadReadPoint() retrieves value from
> a
> > ThreadLocal.
> >
> > Can you specify which operation becomes expensive ?
> >
> > BTW I only found IsolationLevel.READ_UNCOMMITTED
> > in TestRowProcessorEndpoint. Looks like it is not normally used.
> >
> >
> > On Fri, Oct 11, 2013 at 2:20 PM, Vladimir Rodionov
> > <vr...@carrieriq.com>wrote:
> >
> > > Update.
> > >
> > > This method is not called in MemStoreScanner, but direct call to :
> > >
> > > readPoint = MultiVersionConsistencyControl.getThreadReadPoint();
> > >
> > > on every next, seek etc
> > > which is basically the same.
> > >
> > > All these calls become very expensive when you try to achieve 10s of
> > > millions RPS in scan operations.
> > >
> > > Best regards,
> > > Vladimir Rodionov
> > > Principal Platform Engineer
> > > Carrier IQ, www.carrieriq.com
> > > e-mail: vrodionov@carrieriq.com
> > >
> > > ________________________________________
> > > From: Vladimir Rodionov
> > > Sent: Friday, October 11, 2013 2:18 PM
> > > To: dev@hbase.apache.org
> > > Subject: skipKVsNewerThanReadpoint in StoreFileScanner and
> > MemStoreScanner
> > >
> > > From HRegion:
> > >
> > > synchronized(scannerReadPoints) {
> > > if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
> > > // This scan can read even uncommitted transactions
> > > this.readPt = Long.MAX_VALUE;
> > >
> MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
> > > } else {
> > > this.readPt =
> > > MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
> > > }
> > >
> > > If isolation level is READ_UNCOMMITTED than this method should never be
> > > called in both StoreFileScanner and MemStoreScanner
> > > If isolation level is READ_COMMITTED than this method must be called
> only
> > > in MemStoreScanner, because HFiles are immutable no new KV's can be
> added
> > > to HFile after StoreFileScanner was created.
> > >
> > >
> > > Correct?
> > >
> > >
> > > Best regards,
> > > Vladimir Rodionov
> > > Principal Platform Engineer
> > > Carrier IQ, www.carrieriq.com
> > > e-mail: vrodionov@carrieriq.com
> > >
> > > Confidentiality Notice: The information contained in this message,
> > > including any attachments hereto, may be confidential and is intended
> to
> > be
> > > read only by the individual or entity to whom this message is
> addressed.
> > If
> > > the reader of this message is not the intended recipient or an agent or
> > > designee of the intended recipient, please note that any review, use,
> > > disclosure or distribution of this message or its attachments, in any
> > form,
> > > is strictly prohibited. If you have received this message in error,
> > please
> > > immediately notify the sender and/or Notifications@carrieriq.com and
> > > delete or destroy any copy of this message and its attachments.
> > >
> >
>
Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Posted by lars hofhansl <la...@apache.org>.
Taking a quick look... It is easy to reduce the ThreadLocal calls by 50% without any refactoring in the Memstore.
Also thinking about this more, we already have metadata in HFile about the newest memstoreTS; I used that optimize storing the memstoreTS in HFiles away (HBASE-8166 and HBASE-8151).
We could use this during scanning as well and avoid checking against the readpoint altogether.
(might need some refactoring, though, have to checked closer).
-- Lars
----- Original Message -----
From: lars hofhansl <la...@apache.org>
To: "dev@hbase.apache.org" <de...@hbase.apache.org>
Cc:
Sent: Friday, October 11, 2013 6:28 PM
Subject: Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Interesting. Never came up in my profiling of raw scan performance.
Of course my assumption was that the vast majority of all KVs are in HFiles and thus in the blockcache (not the memstore).
ThreadLocals are indeed expensive, we ran into such problems as well (code unrelated to HBase, though).
Mind filing a jira, Vladimir? If there's a perf issue, we should fix it.
-- Lars
________________________________
From: Vladimir Rodionov <vl...@gmail.com>
To: "dev@hbase.apache.org" <de...@hbase.apache.org>
Sent: Friday, October 11, 2013 2:36 PM
Subject: Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Yes, threadLocal.get() is expensive when you count every nanosecond. There
is no need to call it every time in MemStoreScanner.next().
On Fri, Oct 11, 2013 at 2:32 PM, Ted Yu <yu...@gmail.com> wrote:
> MultiVersionConsistencyControl.getThreadReadPoint() retrieves value from a
> ThreadLocal.
>
> Can you specify which operation becomes expensive ?
>
> BTW I only found IsolationLevel.READ_UNCOMMITTED
> in TestRowProcessorEndpoint. Looks like it is not normally used.
>
>
> On Fri, Oct 11, 2013 at 2:20 PM, Vladimir Rodionov
> <vr...@carrieriq.com>wrote:
>
> > Update.
> >
> > This method is not called in MemStoreScanner, but direct call to :
> >
> > readPoint = MultiVersionConsistencyControl.getThreadReadPoint();
> >
> > on every next, seek etc
> > which is basically the same.
> >
> > All these calls become very expensive when you try to achieve 10s of
> > millions RPS in scan operations.
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
> > ________________________________________
> > From: Vladimir Rodionov
> > Sent: Friday, October 11, 2013 2:18 PM
> > To: dev@hbase.apache.org
> > Subject: skipKVsNewerThanReadpoint in StoreFileScanner and
> MemStoreScanner
> >
> > From HRegion:
> >
> > synchronized(scannerReadPoints) {
> > if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
> > // This scan can read even uncommitted transactions
> > this.readPt = Long.MAX_VALUE;
> > MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
> > } else {
> > this.readPt =
> > MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
> > }
> >
> > If isolation level is READ_UNCOMMITTED than this method should never be
> > called in both StoreFileScanner and MemStoreScanner
> > If isolation level is READ_COMMITTED than this method must be called only
> > in MemStoreScanner, because HFiles are immutable no new KV's can be added
> > to HFile after StoreFileScanner was created.
> >
> >
> > Correct?
> >
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
> > Confidentiality Notice: The information contained in this message,
> > including any attachments hereto, may be confidential and is intended to
> be
> > read only by the individual or entity to whom this message is addressed.
> If
> > the reader of this message is not the intended recipient or an agent or
> > designee of the intended recipient, please note that any review, use,
> > disclosure or distribution of this message or its attachments, in any
> form,
> > is strictly prohibited. If you have received this message in error,
> please
> > immediately notify the sender and/or Notifications@carrieriq.com and
> > delete or destroy any copy of this message and its attachments.
> >
>
Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Posted by lars hofhansl <la...@apache.org>.
Interesting. Never came up in my profiling of raw scan performance.
Of course my assumption was that the vast majority of all KVs are in HFiles and thus in the blockcache (not the memstore).
ThreadLocals are indeed expensive, we ran into such problems as well (code unrelated to HBase, though).
Mind filing a jira, Vladimir? If there's a perf issue, we should fix it.
-- Lars
________________________________
From: Vladimir Rodionov <vl...@gmail.com>
To: "dev@hbase.apache.org" <de...@hbase.apache.org>
Sent: Friday, October 11, 2013 2:36 PM
Subject: Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Yes, threadLocal.get() is expensive when you count every nanosecond. There
is no need to call it every time in MemStoreScanner.next().
On Fri, Oct 11, 2013 at 2:32 PM, Ted Yu <yu...@gmail.com> wrote:
> MultiVersionConsistencyControl.getThreadReadPoint() retrieves value from a
> ThreadLocal.
>
> Can you specify which operation becomes expensive ?
>
> BTW I only found IsolationLevel.READ_UNCOMMITTED
> in TestRowProcessorEndpoint. Looks like it is not normally used.
>
>
> On Fri, Oct 11, 2013 at 2:20 PM, Vladimir Rodionov
> <vr...@carrieriq.com>wrote:
>
> > Update.
> >
> > This method is not called in MemStoreScanner, but direct call to :
> >
> > readPoint = MultiVersionConsistencyControl.getThreadReadPoint();
> >
> > on every next, seek etc
> > which is basically the same.
> >
> > All these calls become very expensive when you try to achieve 10s of
> > millions RPS in scan operations.
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
> > ________________________________________
> > From: Vladimir Rodionov
> > Sent: Friday, October 11, 2013 2:18 PM
> > To: dev@hbase.apache.org
> > Subject: skipKVsNewerThanReadpoint in StoreFileScanner and
> MemStoreScanner
> >
> > From HRegion:
> >
> > synchronized(scannerReadPoints) {
> > if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
> > // This scan can read even uncommitted transactions
> > this.readPt = Long.MAX_VALUE;
> > MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
> > } else {
> > this.readPt =
> > MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
> > }
> >
> > If isolation level is READ_UNCOMMITTED than this method should never be
> > called in both StoreFileScanner and MemStoreScanner
> > If isolation level is READ_COMMITTED than this method must be called only
> > in MemStoreScanner, because HFiles are immutable no new KV's can be added
> > to HFile after StoreFileScanner was created.
> >
> >
> > Correct?
> >
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
> > Confidentiality Notice: The information contained in this message,
> > including any attachments hereto, may be confidential and is intended to
> be
> > read only by the individual or entity to whom this message is addressed.
> If
> > the reader of this message is not the intended recipient or an agent or
> > designee of the intended recipient, please note that any review, use,
> > disclosure or distribution of this message or its attachments, in any
> form,
> > is strictly prohibited. If you have received this message in error,
> please
> > immediately notify the sender and/or Notifications@carrieriq.com and
> > delete or destroy any copy of this message and its attachments.
> >
>
Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Posted by Vladimir Rodionov <vl...@gmail.com>.
Yes, threadLocal.get() is expensive when you count every nanosecond. There
is no need to call it every time in MemStoreScanner.next().
On Fri, Oct 11, 2013 at 2:32 PM, Ted Yu <yu...@gmail.com> wrote:
> MultiVersionConsistencyControl.getThreadReadPoint() retrieves value from a
> ThreadLocal.
>
> Can you specify which operation becomes expensive ?
>
> BTW I only found IsolationLevel.READ_UNCOMMITTED
> in TestRowProcessorEndpoint. Looks like it is not normally used.
>
>
> On Fri, Oct 11, 2013 at 2:20 PM, Vladimir Rodionov
> <vr...@carrieriq.com>wrote:
>
> > Update.
> >
> > This method is not called in MemStoreScanner, but direct call to :
> >
> > readPoint = MultiVersionConsistencyControl.getThreadReadPoint();
> >
> > on every next, seek etc
> > which is basically the same.
> >
> > All these calls become very expensive when you try to achieve 10s of
> > millions RPS in scan operations.
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
> > ________________________________________
> > From: Vladimir Rodionov
> > Sent: Friday, October 11, 2013 2:18 PM
> > To: dev@hbase.apache.org
> > Subject: skipKVsNewerThanReadpoint in StoreFileScanner and
> MemStoreScanner
> >
> > From HRegion:
> >
> > synchronized(scannerReadPoints) {
> > if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
> > // This scan can read even uncommitted transactions
> > this.readPt = Long.MAX_VALUE;
> > MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
> > } else {
> > this.readPt =
> > MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
> > }
> >
> > If isolation level is READ_UNCOMMITTED than this method should never be
> > called in both StoreFileScanner and MemStoreScanner
> > If isolation level is READ_COMMITTED than this method must be called only
> > in MemStoreScanner, because HFiles are immutable no new KV's can be added
> > to HFile after StoreFileScanner was created.
> >
> >
> > Correct?
> >
> >
> > Best regards,
> > Vladimir Rodionov
> > Principal Platform Engineer
> > Carrier IQ, www.carrieriq.com
> > e-mail: vrodionov@carrieriq.com
> >
> > Confidentiality Notice: The information contained in this message,
> > including any attachments hereto, may be confidential and is intended to
> be
> > read only by the individual or entity to whom this message is addressed.
> If
> > the reader of this message is not the intended recipient or an agent or
> > designee of the intended recipient, please note that any review, use,
> > disclosure or distribution of this message or its attachments, in any
> form,
> > is strictly prohibited. If you have received this message in error,
> please
> > immediately notify the sender and/or Notifications@carrieriq.com and
> > delete or destroy any copy of this message and its attachments.
> >
>
Re: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Posted by Ted Yu <yu...@gmail.com>.
MultiVersionConsistencyControl.getThreadReadPoint() retrieves value from a
ThreadLocal.
Can you specify which operation becomes expensive ?
BTW I only found IsolationLevel.READ_UNCOMMITTED
in TestRowProcessorEndpoint. Looks like it is not normally used.
On Fri, Oct 11, 2013 at 2:20 PM, Vladimir Rodionov
<vr...@carrieriq.com>wrote:
> Update.
>
> This method is not called in MemStoreScanner, but direct call to :
>
> readPoint = MultiVersionConsistencyControl.getThreadReadPoint();
>
> on every next, seek etc
> which is basically the same.
>
> All these calls become very expensive when you try to achieve 10s of
> millions RPS in scan operations.
>
> Best regards,
> Vladimir Rodionov
> Principal Platform Engineer
> Carrier IQ, www.carrieriq.com
> e-mail: vrodionov@carrieriq.com
>
> ________________________________________
> From: Vladimir Rodionov
> Sent: Friday, October 11, 2013 2:18 PM
> To: dev@hbase.apache.org
> Subject: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
>
> From HRegion:
>
> synchronized(scannerReadPoints) {
> if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
> // This scan can read even uncommitted transactions
> this.readPt = Long.MAX_VALUE;
> MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
> } else {
> this.readPt =
> MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
> }
>
> If isolation level is READ_UNCOMMITTED than this method should never be
> called in both StoreFileScanner and MemStoreScanner
> If isolation level is READ_COMMITTED than this method must be called only
> in MemStoreScanner, because HFiles are immutable no new KV's can be added
> to HFile after StoreFileScanner was created.
>
>
> Correct?
>
>
> Best regards,
> Vladimir Rodionov
> Principal Platform Engineer
> Carrier IQ, www.carrieriq.com
> e-mail: vrodionov@carrieriq.com
>
> Confidentiality Notice: The information contained in this message,
> including any attachments hereto, may be confidential and is intended to be
> read only by the individual or entity to whom this message is addressed. If
> the reader of this message is not the intended recipient or an agent or
> designee of the intended recipient, please note that any review, use,
> disclosure or distribution of this message or its attachments, in any form,
> is strictly prohibited. If you have received this message in error, please
> immediately notify the sender and/or Notifications@carrieriq.com and
> delete or destroy any copy of this message and its attachments.
>
RE: skipKVsNewerThanReadpoint in StoreFileScanner and
MemStoreScanner
Posted by Vladimir Rodionov <vr...@carrieriq.com>.
Update.
This method is not called in MemStoreScanner, but direct call to :
readPoint = MultiVersionConsistencyControl.getThreadReadPoint();
on every next, seek etc
which is basically the same.
All these calls become very expensive when you try to achieve 10s of millions RPS in scan operations.
Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com
________________________________________
From: Vladimir Rodionov
Sent: Friday, October 11, 2013 2:18 PM
To: dev@hbase.apache.org
Subject: skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
>From HRegion:
synchronized(scannerReadPoints) {
if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
// This scan can read even uncommitted transactions
this.readPt = Long.MAX_VALUE;
MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
} else {
this.readPt = MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
}
If isolation level is READ_UNCOMMITTED than this method should never be called in both StoreFileScanner and MemStoreScanner
If isolation level is READ_COMMITTED than this method must be called only in MemStoreScanner, because HFiles are immutable no new KV's can be added
to HFile after StoreFileScanner was created.
Correct?
Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com
Confidentiality Notice: The information contained in this message, including any attachments hereto, may be confidential and is intended to be read only by the individual or entity to whom this message is addressed. If the reader of this message is not the intended recipient or an agent or designee of the intended recipient, please note that any review, use, disclosure or distribution of this message or its attachments, in any form, is strictly prohibited. If you have received this message in error, please immediately notify the sender and/or Notifications@carrieriq.com and delete or destroy any copy of this message and its attachments.