Re: ReadFromBackup, Primary_SYNC, Backups
Manesh, >> When running a large SELECT from a thick client node, could data be >> fetched from the backup instead of primary partitions? readFromBackup=true affects only cache operations, it doesn't work with SQL queries. >> in a two server system, if readFromBackup = False for a cache, and if one >> server fails, would 2nd server stop serving client requests since some partition data is in the backup? no, it will go on serving requests, former backup partitions will turn into primary >> is it possible that readFromBackup=True and Primary_Sync mode for a cache >> could give inconsistent data for cacheMode Replicated in a 2 server node? there's no need to explicitly use readFromBackup with replicated caches. What do you exactly mean by "inconsistent data"? Could you please describe your scenario? >> if I increase backup= 10, in a 2 server system, would it mean that there >> are 10 backups. I am guessing, ignite would keep a single back up on each server, not 5 and 5 on each server. a new backup is created for that cache for any new node joining the cluster. is this right understanding? Yes, that's correct. -- Sent from: http://apache-ignite-users.70518.x6.nabble.com/
Re: ReadFromBackup, Primary_SYNC, Backups
1. Reads mostly go to the primary but yes, in some circumstances it’ll read from the backup with that configuration set to true 2. No. It’ll “rebalance,” which means backup partitions would be promoted to primaries. Your client would still get a response 3. Yes — though in practice the window is very small. Use FULL_SYNC and/or readFromBackup=false if you need to avoid that 4. You’d get one copy per node. Think of it as a target rather than a guarantee > On 3 Nov 2020, at 02:50, Mahesh Renduchintala > wrote: > > Hi > > I have a large SQL table (12 million records) in cacheMode partitioned. > This table is distributed over two server nodes > > > -1- > > When running a large SELECT from a thick client node, could data be fetched > from the backup instead of primary partitions? > Below is the configuration. > > > > > > > > > > /> > > We are seeing some performance improvement, since we made regardFromBackup= > False and a few other things. > > -2- > in a two server system, if readFromBackup = False for a cache, and if one > server fails, > > would 2nd server stop serving client requests since some partition data is in > the backup? > > > -3- > is it possible that readFromBackup=True and Primary_Sync mode for a cache > could give inconsistent data for cacheMode Replicated in a 2 server node? > > > -4- > if I increase backup= 10, in a 2 server system, would it mean that there are > 10 backups. > > I am guessing, ignite would keep a single back up on each server, not 5 and 5 > on each server. > a new backup is created for that cache for any new node joining the cluster. > is this right understanding? > > > > > Strong > > regards > mahesh
Re: ReadFromBackup, Primary_SYNC, Backups
Hi, Can you please give some feedback on the below? From: Mahesh Renduchintala Sent: Tuesday, November 3, 2020 8:20 AM To: user@ignite.apache.org Subject: ReadFromBackup, Primary_SYNC, Backups Hi I have a large SQL table (12 million records) in cacheMode partitioned. This table is distributed over two server nodes -1- When running a large SELECT from a thick client node, could data be fetched from the backup instead of primary partitions? Below is the configuration. /> We are seeing some performance improvement, since we made regardFromBackup= False and a few other things. -2- in a two server system, if readFromBackup = False for a cache, and if one server fails, would 2nd server stop serving client requests since some partition data is in the backup? -3- is it possible that readFromBackup=True and Primary_Sync mode for a cache could give inconsistent data for cacheMode Replicated in a 2 server node? -4- if I increase backup= 10, in a 2 server system, would it mean that there are 10 backups. I am guessing, ignite would keep a single back up on each server, not 5 and 5 on each server. a new backup is created for that cache for any new node joining the cluster. is this right understanding? Strong regards mahesh
ReadFromBackup, Primary_SYNC, Backups
Hi I have a large SQL table (12 million records) in cacheMode partitioned. This table is distributed over two server nodes -1- When running a large SELECT from a thick client node, could data be fetched from the backup instead of primary partitions? Below is the configuration. /> We are seeing some performance improvement, since we made regardFromBackup= False and a few other things. -2- in a two server system, if readFromBackup = False for a cache, and if one server fails, would 2nd server stop serving client requests since some partition data is in the backup? -3- is it possible that readFromBackup=True and Primary_Sync mode for a cache could give inconsistent data for cacheMode Replicated in a 2 server node? -4- if I increase backup= 10, in a 2 server system, would it mean that there are 10 backups. I am guessing, ignite would keep a single back up on each server, not 5 and 5 on each server. a new backup is created for that cache for any new node joining the cluster. is this right understanding? Strong regards mahesh
