[fix](catalog) do cache load when cache value is not present #50188
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run buildall |
TPC-H: Total hot run time: 33735 ms |
TPC-DS: Total hot run time: 192003 ms |
ClickBench: Total hot run time: 30 s |
CalvinKirs
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wuwenchi
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Apr 27, 2025
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### What problem does this PR solve? The MetaCache is used to cache the external table instance, like hive table. The type of cache value is `Optional<Table>`. When first loading a key, if the key does not exist(table not exists), the cacheloader will return `null`, and finally there will be a cache entry `<key, EmptyOptional>` in cache. So when the second time to get this key from cache, the cache will return the `EmptyOptional` instead of try loading this key again from remote datasource. But what we expect is to try loading the key from remote datasource if it does not exist in cache. So we need check the return result of the cache, if return result is `null` or `EmptyOptional`, we should load the key again. Otherwise, the following case may be failed: 1. select a non-exist hive table in Doris. 2. create the table in Hive. 3. select the table in Doris, expect to get table succeed, but still return "table does not exist".
github-actions bot
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Apr 27, 2025
### What problem does this PR solve? The MetaCache is used to cache the external table instance, like hive table. The type of cache value is `Optional<Table>`. When first loading a key, if the key does not exist(table not exists), the cacheloader will return `null`, and finally there will be a cache entry `<key, EmptyOptional>` in cache. So when the second time to get this key from cache, the cache will return the `EmptyOptional` instead of try loading this key again from remote datasource. But what we expect is to try loading the key from remote datasource if it does not exist in cache. So we need check the return result of the cache, if return result is `null` or `EmptyOptional`, we should load the key again. Otherwise, the following case may be failed: 1. select a non-exist hive table in Doris. 2. create the table in Hive. 3. select the table in Doris, expect to get table succeed, but still return "table does not exist".
morningman
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Apr 28, 2025
### What problem does this PR solve? The MetaCache is used to cache the external table instance, like hive table. The type of cache value is `Optional<Table>`. When first loading a key, if the key does not exist(table not exists), the cacheloader will return `null`, and finally there will be a cache entry `<key, EmptyOptional>` in cache. So when the second time to get this key from cache, the cache will return the `EmptyOptional` instead of try loading this key again from remote datasource. But what we expect is to try loading the key from remote datasource if it does not exist in cache. So we need check the return result of the cache, if return result is `null` or `EmptyOptional`, we should load the key again. Otherwise, the following case may be failed: 1. select a non-exist hive table in Doris. 2. create the table in Hive. 3. select the table in Doris, expect to get table succeed, but still return "table does not exist".
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koarz
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Jun 4, 2025
…50188) ### What problem does this PR solve? The MetaCache is used to cache the external table instance, like hive table. The type of cache value is `Optional<Table>`. When first loading a key, if the key does not exist(table not exists), the cacheloader will return `null`, and finally there will be a cache entry `<key, EmptyOptional>` in cache. So when the second time to get this key from cache, the cache will return the `EmptyOptional` instead of try loading this key again from remote datasource. But what we expect is to try loading the key from remote datasource if it does not exist in cache. So we need check the return result of the cache, if return result is `null` or `EmptyOptional`, we should load the key again. Otherwise, the following case may be failed: 1. select a non-exist hive table in Doris. 2. create the table in Hive. 3. select the table in Doris, expect to get table succeed, but still return "table does not exist".
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What problem does this PR solve?
The MetaCache is used to cache the external table instance, like hive table.
The type of cache value is
Optional<Table>.When first loading a key, if the key does not exist(table not exists), the cacheloader
will return
null, and finally there will be a cache entry<key, EmptyOptional>in cache.So when the second time to get this key from cache, the cache will return the
EmptyOptionalinstead of try loading this key again from remote datasource.
But what we expect is to try loading the key from remote datasource if it does not exist in cache.
So we need check the return result of the cache, if return result is
nullorEmptyOptional,we should load the key again. Otherwise, the following case may be failed:
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