PFB Following questions:
1) In my local, I don't have a networkMap so the maxTransactionSize and maxMessageSize needs to be made part of the extraConfig in deployNodes for each node?
2) Let's say I have an Excel of 100MB which I Zip and then upload to Node using rpc.uploadAttachment the SecureHash received will now be added to a Tx. After Successful Completion of the TX will both parties have the attachment? or The Receiver will get the file only when he opens the attachment?
3) If it's when the receiver opens the attachment, it's requested from the sender, the file travels over the network and reaches to the receiver and is stored in the H2 DB for future use. If attachment is required later, the blob can directly be provided from the DB?
4) Now where, how does attachmentContentCacheSizeMegaBytes come into picture? Since we are already storing it in the H2 DB where is it used? as a blob limit to the node_attachment table?
5) Also, is the file ever stored in the file system ? at the time of upload to the node? does it get stored directly to the H2 DB?
The maxTransactionSize and maxMessageSize is set by the network operator, and individual nodes cannot modify it. This is for compatibility reasons. All the nodes on the network need to be able to handle the largest-possible transaction to ensure they can resolve any transactions they receive
The receiver node downloads the attachment immediately, and not when it first opens the attachment
N/A
The attachmentContentCacheSizeMegaBytes node configuration option is optional and specifies how much memory should be used to cache attachment contents in memory. It defaults to 10MB
The attachment is stored in the node's database as a blob when it is first uploaded
Related
I get the neural-TTS file Azure sent me but I do not store store the file in the system directly, rather I want to first know the duration and/or the size of the file to decide where I will store it after... Can I get such data from the response Azure sends? Or in any other way?
Once Corda node failed, what is the appropriate process of recovery? Corda transactions are shared only with qualified nodes for specific business network, not with every nodes. Therefore, when recovering failure node, copying data from other node would not work well, recovering from backup is required. However, backup image is not completely same for other correct nodes, I would like to know how recover consistency of corda node.
Node data storage
A Corda node stores its vital information as follows:
The node's data is stored in a standard SQL database
By default, in an H2 database file called persistence.mv
The node's keys and certificates are stored in Java keystores in the certificates folder
Recovery from node crashes
If the node crashes:
The database and the contents of the certificates folder will not be affected
In-flight flows can be restarted from their most recent checkpoint
Artemis messages can be replayed
In other words, you can generate a new node, re-add the persistence.mv file, certificates folder and CorDapps, and the node will behave as if nothing happened when you start it up again.
Recovery from corruption/deletion of the node's files
Loss/corruption of data is non-fatal as long as you are able to recover:
The node's database
The contents of the node's certificates folder
It is the responsibility of the node's owner to ensure they protect and back-up these files using standard business procedures. If both of these can be recovered and re-added to a new node, the node should spin up as usual.
If the contents of the node's certificates folder cannot be recovered, you will no longer have your private key, and will not be able to spend your assets on the ledger.
If certain pieces of data cannot be recovered from the node's database, the node could attempt to re-request this data from other nodes where applicable (e.g. the transaction history). However, there is no way to force the counterparties to share this information.
I am streaming a Avro encoded file over the network from a S3 compliant object store and trying to read it and put it in some data-structure.
Issue: The issue I am facing sometimes ( one or two times in one / two days in test node when running continuously) is that half way through the file it hits this exception Invalid sync! in the nextRawBlock() method in DataFileStream class.
I would like to detect the root-cause of this and fix. I have been trying to
reproduce this in a test app but unable to do so successfully. I am looking for ideas on
what might potentially cause this ?
any better ways of reproducing this.
More details
a) The Avro file is not downloaded to disk , I get a handle to the file stream using S3ObjectInputStream and feed it to DataFileStream constructor
and then read from the stream directly.
b) The app tries to read records from the Avro encoded file in batches
of 500 records at a time.
c) The file contains a header section containing a Long count and a KV Map of String to Integer. After that it contains a array of records where each record contains a String and a long array. The schema uses Avro's union construct for enabling this.
d) Number of records in the file on average is around 5M
e) This entire download happens in separate thread and not in any user request.
f) The file is uploaded to the store by a separate process.
Other observation:
a) Upon failure the app closes the stream and tries to again download and read the stream. What I observe is this takes the node to a high oldgen state slowing down user requests.
I am using sqlite in my application only for read access. The DB gets hit often by my application and I could see that the header(100 bytes) of the database is read every time when i access the database.
Precisely speaking, 16 bytes from the 24th byte of the header is read everytime. My question is , if the database is used only for read purpose, why the header is read everytime as the database connection is not closed?..can we make it read it only once?
Thanks!!
Google search gave me this link, and it says
"Your process may promise that it will only read the database, but there
might be some other process writing to it.
Not being a server, sqlite has no other way to find that out than by
reading the header over and over again. It has to check whether the
schema was changed, or whatever other info is in those bytes."
http://www.mail-archive.com/sqlite-users#sqlite.org/msg69900.html
1.
I have created a audio player in silverlight.
within that player user is able to select a portion of song to save as ringtone.
but i got the time duration from .. but I have to cut the partial portion of stream or audio stream and save it to the server dick.
Plz suggest me how I can convert the selected audio time duration into the stream or byte array..?
-- Additional information on this question:
2.
I have created a ringtone audio player in silverlight. Within that user can select a portion which can be cut and save as a audio file.
I am unable to save the stream to the disk.. it is giving following errors:
Error 1. Attempt to access the method failed System IO FileInfo OpenWrite
Plz help
-- Additional information on this question:
3.
What are the use of MediaStreamSample & MediaStreamSource class in silverlight with respect to MediaElement?
Will it help in cutting a portion of audio file in order to create the ringtone out of a song?
If you need to save to the server, then you need to get that data to the server.
Just saving it (as answered) will try to save to the client's machine. What you need to do is upload the data to the server either via a WCF service or an ASHX handler or such. I've done something similar -- uploading MP3 files from a Silverlight client to a WCF service via a Stream, works well.
Next: You need to make sure that whatever splitting process you use accommodates the audio format-- ie you probably just can't split the binary file. What format are you using, mp3?
I've used something called mp3plt, before to split mp3s. You may be able to recompile the source into a Silverlight-compatible library, assuming it's written in something you can use, source here.
Or you can look into the mp3 specs to see if it is possible to just split the binary file, in which case taking the duration to cut (the one the user chose), and multiplying by the bitrate, (kb/s * seconds = kb) will give you the place in the file byte[] you can cut at.
Error 1. Attempt to access the method failed System IO FileInfo OpenWrit, you getting this error coz of security reasons. Before saving to disk you should promt SaveFileDialog to user, and then only save file to disk.