a keyspace id, and at the same time, it needs to save that data so that it can be used later when Map is called. Solution In order to support the new use cases, the following changes can be made: 1 function exists for the primary vindex, the insert will call it. Otherwise, it will use the regular Map function. 4. If the vindex is owned, then the regular code for an owned vindex is executed, even if instead of just reusing the Map function? This is to address the first use case. In the first use case, the MapNew function will generate a random keyspace id, whereas the Map function will perform the lookup

a keyspace id, and at the same time, it needs to save that data so that it can be used later when Map is called. Solution In order to support the new use cases, the following changes can be made: 1. function exists for the primary vindex, the insert will call it. Otherwise, it will use the regular Map function. 4. If the vindex is owned, then the regular code for an owned vindex is executed, even if instead of just reusing the Map function? This is to address the first use case. In the first use case, the MapNew function will generate a random keyspace id, whereas the Map function will perform the lookup

a keyspace id, and at the same time, it needs to save that data so that it can be used later when Map is called. Solution In order to support the new use cases, the following changes can be made: 1. function exists for the primary vindex, the insert will call it. Otherwise, it will use the regular Map function. 4. If the vindex is owned, then the regular code for an owned vindex is executed, even if instead of just reusing the Map function? This is to address the first use case. In the first use case, the MapNew function will generate a random keyspace id, whereas the Map function will perform the lookup

. . . . . . . . . . . 507 vtexplain -vschema-file vschema.json -schema-file schema.sql -ks-shard-map shardmaps.json -replication-mode “ROW” -output-mode text -sql “SELECT FROM users; SELECT FROM users a keyspace id, and at the same time, it needs to save that data so that it can be used later when Map is called. Solution In order to support the new use cases, the following changes can be made: 1 function exists for the primary vindex, the insert will call it. Otherwise, it will use the regular Map function. 4. If the vindex is owned, then the regular code for an owned vindex is executed, even if

what the vindex definition looks like: "region_vdx": { "type": "region_json", "params": { "region_map": "/vt/examples/region_sharding/countries.json", "region_bytes": "1" } }, And we use it thus: "customer": a config file. You will need to edit the value of the region_map parameter in the vschema file main_vschema.json. For example: "region_map": "/home/user/my-vitess/examples/region_sharding/countries.json" very lightweight connections. Vitess’ connection pooling feature uses Go’s concurrency support to map these lightweight connections to a small pool of MySQL connections. As such, Vitess can easily handle

very lightweight connections. Vitess’ connection pooling feature uses Go’s concurrency support to map these lightweight connections to a small pool of MySQL connections. As such, Vitess can easily handle Tablet Alias (cell+unique id) that uniquely identifies the Tablet. • the Hostname, IP address and port map of the Tablet. • the current Tablet type (master, replica, batch, spare, …). • which Keyspace / Shard Shard the tablet is part of. • the sharding Key Range served by this Tablet. • user-specified tag map (e.g. to store per-installation data). A Tablet record is created before a tablet can be running (either

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Map Reduce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . very lightweight connections. Vitess’ connection pooling feature uses Go’s concurrency support to map these lightweight connections to a small pool of MySQL connections. As such, Vitess can easily handle Tablet Alias (cell+unique id) that uniquely identifies the Tablet. • the Hostname, IP address and port map of the Tablet. • the current Tablet type (master, replica, batch, spare, …). • which Keyspace / Shard

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Map Reduce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . We will discuss this in the advanced section. NOTE: For some use cases, customer_id may actually map to a tenant_id. In such cases, the cardinality of a tenant id may be too low. It’s also common that very lightweight connections. Vitess’ connection pooling feature uses Go’s concurrency support to map these lightweight connections to a small pool of MySQL connections. As such, Vitess can easily handle

Golang ? • minimalist • goroutines • channels & selects • closures • defers • generics • GC • map, slices • performace • java < go < c/c++ Vitess Features • dynamic resharding • auto-failover