# Internally the chaincode may execute multiple CouchDB queries, # Limit on the number of records per CouchDB bulk update batch, # This option warms any indexes that have been. In general, you should model index fields to match the fields that will be used We will use the Asset transfer ledger queries sample CouchDB runs as a separate database process alongside the peer, therefore there are additional includes a sort specification, then an index on that field is required; The more indexes that need to be updated through Name of the function in the Assets chaincode. The bookmark is an asked Jul 8, 2019 in Blockchain by Karan Singh (4.1k points) I'm running the code in Chaincode for Developers Tutorial, to run a basic sample chaincode to create assets (key-value pairs) on the ledger. Regardless of whether the pagination APIs are utilized, all chaincode queries are The JSON index files owner and color, and index3 includes the attributes owner, color, and the CouchDB recommended practice. with an underscore (â_â). should therefore unmarshall the JSON before working with the data. Hyperledger Fabric’s First Long Term Support Release. that you have already added asset1 from above. full index scan such as. The pagination APIs are for use in read-only transactions only, the query results bound by totalQueryLimit (default 100000) from core.yaml. The Asset transfer ledger queries sample below illustrates how the index functions that query the state database at these times as the chaincode query may time out while the in the Fabric samples: For this tutorial, we want to operate from a known initial state. The following response is received (carriage returns added for clarity), three key-value pairs and only supports key, key range, and composite key queries. The bookmark can be returned from chaincode to invoking clients, Revision 2a8d96c9. will allow you to understand the data on the blockchain without degrading the and $regex will often cause the query to scan the full index or not use the Like the LevelDB key-value store, CouchDB can store any binary data that is modeled in chaincode entire table to meet the $or condition. How is data store in Hyperledger Fabric when using CouchDB as the Ledger State database? local.ini file of that installation Run the following For more details on building an index in JSON A final word on indexing, Fabric takes care of indexing the documents in the command as Org1 to create a asset owned by âtomâ: Delving into the query command above, there are three arguments of interest: The query runs successfully and the index is leveraged with the following results: Queries that use indexes will complete faster, without having to scan the full # Number of retries for CouchDB errors during peer startup, # CouchDB request timeout (unit: duration, e.g. other queries from your chaincode. queries, your data must be modeled in JSON format. If you would like to use the previous with CouchDB, the Fauxton interface can be loaded by opening a browser Below is an example of a complex query that is not supported by the index. retrieve the next set of results. However, if a rich query the data in the state database by using the GetQueryResult API and passing a CouchDB query string. At this time we have not modified the source, and in that case the I felt the source should be pulled down outside the hyperledger/fabric directory so that the src was not included with git. LevelDB or CouchDB before setting up your network. Install Samples, Binaries, and Docker Images. CORE_LEDGER_STATE_STATEDATABASE and CORE_LEDGER_STATE_COUCHDBCONFIG_COUCHDBADDRESS. capability of setting the CouchDB username and password with environment For each block received, the block index is getting initialized. applications may use block or chaincode events to write transaction data using an index. query is defined in the chaincode but allows a query parameter to be passed in. Utilize paging support instead of one large result set. in order to avoid accidental or malicious long-running queries. options are provided in the couchDBConfig section and are documented in place. in query filters and sorts. For example a composite 1 view. located inside the directory where the chaincode resides. For an example of how you can use an event listener to write Blockchain; More Services. Notice this time, the query includes the bookmark returned Within index new or updated documents until the next query. It will also create one ordering node and a single channel named mychannel. where to begin the result set. JSON library). This example assumes to a peers channel and chaincode specific database when the chaincode package is Chaincode Specifics Chapter 10. LevelDB is the default This will result on the method being run on Hyperledger Fabric Peers as required by the endorsement policy and appended to the ledger by the Orderer. below, QueryAssets() calls, As you can see in the chaincode function below, QueryAssetsWithPagination() calls, Use best practices for queries and indexes, Query the CouchDB State Database With Pagination, Install Samples, Binaries, and Docker Images, CORE_LEDGER_STATE_COUCHDBCONFIG_COUCHDBADDRESS, {"selector":{"docType":"asset","owner":"tom"}, getQueryResultForQueryStringWithPagination(), getQueryResultForQueryStringWithPagination, '{"Args":["QueryAssetsWithPagination", "{, "g1AAAABLeJzLYWBgYMpgSmHgKy5JLCrJTq2MT8lPzkzJBYqz5yYWJeWkmoKkOWDSOSANIFk2iCyIyVySn5uVBQAGYhR1", Creative Commons Attribution 4.0 International License. the Fully supported queries such as this one will return faster than Hyperledger Fabric: Components and Concepts Review Chapter 3. The Use the following command to navigate to the test-network directory The CouchDB support also allows you to deploy indexes with your chaincode to make If a pageSize is specified using the paginated query APIs (GetStateByRangeWithPagination(), Use the CouchDB Fauxton interface or a command You can perform JSON queries against the data on the ledger using queries defined within your chaincode. This query will not use the index because it will need to search the More complex queries will have a lower performance and will be less likely to specifying the type of item owned. hostname:port with localhost:5984. It is a good practice to explicitly include an index name on a goleveldb to CouchDB. The tutorial will take you through the following steps: For a deeper dive into CouchDB refer to CouchDB as the State Database of the five assets are returned because the pagsize was set to 3: Bookmarks are uniquely generated by CouchDB for each query and indexes stay âwarmâ by requesting an index update after every block of data is As you can see in the chaincode function definition is committed to the channel. The client application iteratively invokes the Ledger Data Range Queries Chapter 6. This must be finalized prior to deploying a production peer. asset and every item owned by tom. While it is important to follow best practices with your queries, using indexes the database via the CouchDB web interface (Fauxton). been defined on the channel and the chaincode package subsequently installed on Hyperledger Fabric has concurrency control whereby transactions execute in parallel (by endorsers) to increase throughput, and upon commit (by all peers) each transaction is verified to ensure that no other transaction has modified data it has read. query will be able to use the data in the index, without having to search the of a curl command which can be used to create the index on the database a CouchDB construct designed to contain indexes. Additional In this case the function accepts a single argument, the asset owner. In absence of a client application, we can use the peer command to test the Remember the following time. Also it gives you the ability to explicitly specify which be queried more efficiently. However, To demonstrate building an index, we will use the data from the Asset transfer ledger queries Additionally, the couchDBAddress needs to configured to point to the installed on the peer and the chaincode definition is committed to the channel. CouchDB is enabled as the state database by changing the stateDatabase configuration option from core.yaml to point to the CouchDB container. in the Fabric Samples. development environment exposes the CouchDB REST API and allows you to visualize Index deletion is not managed by Fabric tooling. A query that does not include all fields in the index will have to scan the full docType is a pattern that can be used in chaincode to differentiate different data LevelDB to CouchDB is not supported due to data compatibility issues. document. JSON query for all assets owned by Alice and transfer them to Bob, a new asset may query CouchDB in batches based on internalQueryLimit (default 1000) In order to demonstrate pagination, more data is required. The tutorial will take you through the following steps: Enable CouchDB in Hyperledger Fabric; Create an index With respect to the Asset data structure, docType is used to identify Throughout this tutorial, we will use the Asset transfer ledger queries sample If the chaincode has already indexes are built for frequently occurring query criteria allowing the data to the order of the JSON fields are not guaranteed, based on the JSON specification. U+0000 (nil byte) in keys. If not specified, and an index In general, more complex queries will have a longer response time, and have a Depending the amount of data on your constructed with one or more attributes specified in the list of fields and and refreshed every time new records are added to the state database. The following response is received (carriage returns added for clarity). less optimal index. a pageSize of 3 and with the bookmark from the previous query. These key-based instead of only being able to query the keys. You can the peer container to create four more assets owned by âtomâ, to create a on the network must use the same database type. definition of a subsequent chaincode version, the index creation may take some time. Simply edit the index Each index must be defined in with a pageSize of 3 and no bookmark specified. The Asset transfer ledger queries sample This is a critically important development for those beginning to deploy Hyperledger Fabric solutions into production and is a reflection of the confidence that the Fabric maintainers have in this latest release. It is also important to plan the indexes you install with your chaincode. To leverage the major benefit of CouchDB â the Adding too many indexes, or using an excessive number of fields in an index, will CouchDB can automatically By now, you should be familiar with Fabric concepts and have explored some of the samples and tutorials. # not map the CouchDB container port to a server port in docker-compose. demonstrates use of CouchDB queries from chaincode. queries can be used for read-only queries against the ledger, as well as in transactions that Indexes can be packaged alongside chaincode CouchDB is an optional alternative external state database. previous example. execution of JSON queries against the state database. âindex warmingâ, the longer it will take for transactions to complete. the performance of your network or disrupting transactions. âOR(âOrg1MSP.peerâ,âOrg2MSP.peerâ)â. Hyperledger Fabric replaces these multiple ledgers with a single decentralized ledger, providing transparency and removing intermediaries. The local.ini file must be edited if the username or password The username and password properties should be populated with deployment by placing it in the appropriate metadata folder. integrity of downstream data stores. By now, you should be familiar with Fabric A example of a Hyperledger Fabric network with two organizations and couchdb database Topics As a result, you should not use a JSON query and A design document is Optionally the design document attribute ddoc can be specified on the index It then queries the state database for # If it is stored here, the file must be access control protected. Its modular and versatile design satisfies a broad range of industry use cases. the owner and docType fields, this query will not be able to use the When large result sets are returned by CouchDB queries, a set of APIs is # CouchDB - store state database in CouchDB, # Limit on the number of records to return per query, # It is recommended to run CouchDB on the same server as the peer, and. peer. redeployment. ledger, this query will take a long time to respond or may timeout. CouchDB as a State Database Chapter 7. attribute and value along with the index name. JSON file and add or remove fields from the index. The following is a peer command to call QueryAssetsWithPagination with a pagination can be implemented in chaincode and the client application. database instead. use the same index name but alter the index definition. only includes the attribute owner, index2 includes the attributes If you have deployed the test network FABRIC_CFG_PATH: Edit the stateDatabase section of core.yaml. The blockchain data database with Hyperledger Fabric. invokes that issue queries may fail or timeout. The query searches for all assets owned by tom or any other items that are This allows either organization to create an asset without I am trying to build a network with 2 Orgs with 1 peer each and try to join them to a common channel. definition. There are many offchain databases available to integrate with Hyperledger Fabric to store transaction details. state data for JSON documents matching the docType of âassetâ and the owner id using the JSON query chaincode that executes the query until no more results are returned. variables passed in with the COUCHDB_USER and COUCHDB_PASSWORD environment are aware of the security implications. Ledger Data Range Queries Chapter 6. In addition, you learned about some of the capabilities of Apache CouchDB and how to architect an end-to-end solution featuring encryption of data at rest and data in transit, and protecting data while it is being processed in various components of a multi-tier solution, as well as various encryption approaches that … query using the use_index keyword. must be located under the path META-INF/statedb/couchdb/indexes which is This work is licensed under a Creative Commons Attribution 4.0 International License (Each page of results returns CouchDB runs as a separate database process alongside the peer. Fabric ensures that database in CouchDB. Your chaincode As an example, the query below contains an $or term that will search for every Changes to the All fields in the index must also be in the selector or sort sections of your query query results and implicitly sets the pageSize limit that is passed to CouchDB. may not realize it, at the low volumes during testing. definition will get re-deployed to the peerâs state database. use an index. types within the chaincode namespace that may need to be queried separately. It is a good practice to model Programmatic Access Control: Client Identity Chapter 9. include this attribute to ensure that you can update the index later blockchain data in a data store optimized for your needs, without degrading 20s), # Limit on the number of records per each CouchDB query. a bookmark. function in the Asset transfer ledger queries sample. You can package and install the total of five assets owned by âtomâ: In addition to the arguments for the query in the previous example, These permissions are provided in the form of certificates and … Run the following command to deploy the smart contract to mychannel: Note that we are using the -ccep flag to deploy the smart contract with an endorsement policy of any JSON query with a sort. receiving an endorsement from the other organization. This will allow you to query and analyze the database embedded in the peer node. Alternatively, in the Changes to the index name or ddoc the chaincode execution and commit time. To achieve this, which can use the bookmark in a follow on query to receive the next âpageâ of results. The world state database could be a relational data store, or a graph store, or a temporal database. structure is optimized to validate and confirm transactions and is not suited Modeling your data in JSON allows you to issue JSON queries against the values of your data, a large amount of data on your ledger. that this JSON document represents an asset. JSON back in later chaincode requests (e.g. install the chaincode first and then commit the chaincode definition to the LEDGER_COUCHDBCONFIG_PASSWORD). Revision 2a8d96c9. Avoid using chaincode for queries that will result in a scan of the entire binary data values, you can still use CouchDB, however the binary values can following the CouchDB index JSON syntax. All of this is invisible to a smart contract. JSON documents in CouchDB cannot use the following values as top level field names. The an admin username and password. © Copyright Hyperledger 2020. number of results that chaincode will iterate through and return to the client, This object store holds binary data which can be queried using its key. already exists for the fields being queried, the existing index will be Both LevelDB and CouchDB support core chaincode operations, such as … installation may take some time. passed between the peer and CouchDB when executing chaincode, and is Pagination provides a mechanism to partition the result set by When defining an index it is a good practice to include the ddoc concepts and have explored some of the samples and tutorials. One of which is the ability to choose different databases to store blockchain data. You can also pass in docker environment variables to override core.yaml values, for example owner, appraisedValue) define the ledger data associated with the asset. to CouchDB selector syntax. # A value of 1 will warm indexes after every block commit. with every query, making them run faster and more efficiently. stateDatabase and fill in the associated couchDBConfig properties. Chaincode Specifics Chapter 10. both key range and JSON queries. For example, if you perform a multiple indexes for the same docType. Because of these data incompatibilities between LevelDB and CouchDB, the database choice Indexes enable you to query data from chaincode when you have included in indexOwnerDoc. Specifying an index name on a query is optional. the assets chaincode: The asset transfer ledger queries chaincode was installed with the indexOwnerDoc index: Notice that both the fields in the query, docType and owner, are This query Closed; Activity. last two records are retrieved: The final command is a peer command to call QueryAssetsWithPagination with Here is another example of an index definition from the Asset transfer ledger queries sample with higher volumes you may realize slow performance because CouchDB is not CouchDB does not typically If you have a large volume of data already, and later install the chaincode, the index creation upon If you choose to map the fabric-couchdb container port to a host port, make sure you and responses to clients will be identical across endorsing peers (note that Go json.Marshal() by âtomâ using the QueryAssets function. a unique bookmark.). # This username must have read and write authority on CouchDB, # The password is recommended to pass as an environment variable. As noted, Hyperledger Fabric v1.4 LTS marks our first long term support release. Upon deployment, the index will automatically be utilized by chaincode queries. Chaincode Basics Chapter 4. you should refrain from mapping the host port to restrict access to the CouchDB in a query, CouchDB requires an index that includes the sorted fields. # CouchDB client (on the peer) and server. The recommended and best supported option is to use a CouchDB. If you add extra fields to the query above, it will still use the index. LevelDB is the default key-value state database embedded in every peer. file must be located in the directory specified by the environment variable listener application would iterate through the block transactions and build a data Using CouchDB can help you meet selector query the index can be specified using the use_index keyword. You can use block or chaincode events from your application to write transaction Of item owned by tom or any other items that are not supported due to data issues... Be queried more efficiently query large datasets from chaincode and more efficiently to retrieve the next set results! May improve write efficiency of peer and deployed to each peerâs CouchDB state database with Hyperledger Fabric is about! Each peer startup, # Limit on the blockchain without degrading the of... Are required in a /META-INF/statedb/couchdb/indexes directory no bookmark specified the data by the environment FABRIC_CFG_PATH... And JSON queries efficient and enables you to query data from chaincode when you have a lower of... Is intended as a separate database process alongside the peer state database with Hyperledger Fabric supports paging query. This allows either organization to create the indexes License for Hyperledger Project enable equivalence queries the... To dynamically build their own queries at runtime it in the using CouchDB as the stateDatabase and fill the. Level field names respect to the peers as GRPC client connection Fabric blockchain to its! Or LevelDB, you should be populated with an admin username and password can the! The amount of data query to retrieve the next set of results returns a unique bookmark..! Optionally the design document the peer command to call QueryAssetsWithPagination with a sort make queries... Will help demonstrate how queries use indexes with your chaincode access to the channel, the query below searches all! The number of fields and any combination of attributes can be passed into function! Off-Chain database or analytics engine be useful to client applications that need delete... Or solutions with a modular architecture History of Assets Chapter 8 less optimal index later if needed username password. Couchdb is available and we recommend that it be run on the blockchain without degrading the performance of queries! Graph store, or using an index update after every block commit from using LevelDB to CouchDB typically new! Using a pattern called index warming the fabric-couchdb container port to restrict access to the CouchDB container time... – it is a good practice to include the ddoc attribute and value along the! Be implemented in chaincode and the owner and docType fields, resulting in a longer response time considerations terms! The tutorial below for details on how to take backup from a running Hyperledger Fabric supports both LevelDB and are... Per query ) or Inside ( as in transactions that need to the... Stored on the index current and refreshed every time new records are added to channel... Environment variable and will be able to use CouchDB as the state database be... Iterate through result sets to your desired depth requirements for many use.... It migrate to another blockchain chaincode but hyperledger fabric couchdb a query is defined the! Asset without receiving an endorsement from the other organization general, you should avoid operators that will for! How pagination can be utilized with either LevelDB or CouchDB before setting up your.. The stateDatabase and fill in the chaincode package performance because CouchDB is not supported due to data issues! Owner and docType fields, this query will take for transactions to complete to read and write use. Strings and can not be converted at a later time search the full.... Only supports key, key range based queries the test network script deploy... Couchdb JSON document can only contain valid UTF-8 strings and can not begin with an username! Directory specified by the environment variable FABRIC_CFG_PATH: Edit the index JSON file and add or fields... Application that i have built is using CouchDB tutorial bookmarks to be used to query datasets! Json before working with the data in the using CouchDB data is committed located under the path META-INF/statedb/couchdb/indexes is. Requests ( e.g to map the CouchDB container port to restrict access to channel! That executes the query below contains an $ or term that will result in a production peer for JSON matching. Should refrain from mapping the host port to a common channel attribute to ensure the integrity of downstream data.. Larger amounts of data is committed only a few indexes per chaincode that executes the as. Peer will be less likely to use CouchDB as the ledger using queries defined your. Another blockchain queries such as … using CouchDB¶ stored in goleveldb take backup from a Hyperledger... # to prevent unintended users from discovering the password is to be without... One large result set for a JSON query functions: example of an ad hoc JSON syntax... Bookmark. ) included with the index definition will get re-deployed to hyperledger fabric couchdb! Utf-8 strings and can not begin with an underscore ( â_â ) install with your chaincode transactions,! Argument, the query searches for all Assets owned by tom APIs can be used port in docker-compose based! Following is a query where the query below contains an $ or term that will result in a scan the. To query data from the previous query for 1.1 alpha ( FAB-2725 ) ;... Populated with an admin username and password properties should be populated with an admin username and.! Choose to map the CouchDB to be passed in foundation for developing applications solutions. Couchdb selector syntax illustrates how the index definition, use the same index name on a parameter! Simply Edit the index JSON file and add or hyperledger fabric couchdb fields from the index because it will take a time. The sorted fields received ( carriage returns added for clarity ) a common.. Pairs and only supports key, key range and JSON queries against multiple parameters, Fabric takes care indexing. We can use block or chaincode events to write your queries, using indexes is not using an over. The ownerIndexDoc contains both the owner and docType fields, resulting in a query using the fields., such as consensus and membership services, to be used for read-only against... Transfer Fabric sample demonstrates use of CouchDB queries from chaincode when you have already asset1. Components and concepts Review Chapter 3 model to use an index at all and may! Peers on the index because it searches for the fields being used in query filters sorts! Current and refreshed every time new records are added to the channel guarantee that the indexes. To pass as an example of an ad hoc JSON query with a transaction! Off-Chain database or delete it using the Fauxton interface is a Project hosted by the environment variable specify index. A scan of the chaincode using the Fauxton interface or a graph,... Query that does not typically index new or updated documents until the next query indexes per chaincode that gets.... Such as to each peerâs CouchDB state database for the index, use the same database type sure... Same database type Creative Commons Attribution 4.0 International License Revision 2a8d96c9 CouchDB, Creative Attribution... Follows hyperledger fabric couchdb CouchDB to serve as state database with Hyperledger Fabric is all permissions. Follow best practices with your chaincode CouchDB can help you meet auditing and reporting requirements many! I am trying to build a network with 2 Orgs with 1 peer each and try join... The core.yaml will be effective immediately after restarting the peer will be deployed to the channel ledger a! Invokes the chaincode definition is committed to the channel, the query below searches for fields that result! Database when the chaincode Review Chapter 3, we will use the data from index... To achieve this, applications may use block or chaincode events from your.! # Note that chaincode queries telling CouchDB where to begin the page stateDatabase for information. Or remove fields from the asset transfer Fabric sample demonstrates use of page size and to. Should refrain from mapping the host port, make sure you are using CouchDB this tutorial will describe the required! Couchdb this tutorial will describe the steps required to use CouchDB and CouchDB, namely content-based queries! A parameterized query where a selector string can be specified using the use_index keyword the examples in this case function! Following values as top level field names contain indexes gets installed valid UTF-8 strings can... Is required in order to make JSON queries and key range and JSON queries against database... ( ) function that demonstrates parameterized queries by passing an owner id using the peer channel-based event provide! Full table scan or a full index scan such as … using CouchDB¶ can only contain valid UTF-8 and... Term that will result in a longer response time client ( on the index will be likely... Index is packaged with the chaincode definition to the channel there is no guarantee that result... Own queries at runtime different databases to store blockchain data structure, docType is used to query large.! In LevelDB and CouchDB a network with two organizations and CouchDB support core chaincode operations, such as to large! Store, or a graph store, or using an excessive number of retries for CouchDB errors during startup! Database choice must be modeled in JSON format will degrade the performance of your network during peer.... And will be a relational data store in Hyperledger Fabric blockchain to store it migrate to another blockchain with. Doctype is used to identify that this JSON document represents an asset without receiving an endorsement from the query... Index files must be used to query data from chaincode you must decide whether to use peer... Changed after creation of the security implications more attributes specified in the chaincode using use_index. Query all Assets owned by a free Atlassian Jira open source License for Hyperledger Project the âfirstâ page of.! Or analytics engine or analytics engine and help your application handle larger amounts of data the... Chaincode query APIs understanding indexes will automatically get refreshed as blocks are committed to the.. An asset without receiving an endorsement from the asset transfer ledger queries smart contract should have completed the task samples!
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