Introduce "use database" and update gaiac usage #633
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chuan
requested review from
simone-gaia,
senderista,
LaurentiuCristofor and
daxhaw
and removed request for
senderista
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| # | ||
| # Generate stand alone incubator. | ||
| # | ||
| add_custom_command( | ||
| COMMENT "Compiling incubator.ddl..." | ||
| OUTPUT ${GAIA_GENERATED_SCHEMAS}/gaia_barn_storage.h | ||
| COMMAND ${GAIA_GENERATE} --destroy-db -t ${GAIA_PROD_BUILD}/db/core -o ${GAIA_GENERATED_SCHEMAS} -g ${INCUBATOR_DDL} | ||
| COMMAND ${GAIA_GENERATE} --destroy-db -t ${GAIA_PROD_BUILD}/db/core -o ${GAIA_GENERATED_SCHEMAS} -d barn_storage -g ${INCUBATOR_DDL} |
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Why is the folder called "barn_storage" when the command says "incubator"?
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Ah, so the database for "incubator" is called "barn_storage". Using two names for this test is rather confusing. Why not have the database called incubator as well? Or just stick to barn_storage.
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For prerequisites, the ddl and the database use the same name. It would be nice to come up with some consistent naming scheme to eliminate surprises about what is called which way.
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I agree. But this is how this script/schema is currently written and used by many tests.
| @@ -21,6 +21,11 @@ void initialize_catalog() | |||
| ddl_executor_t::get(); | |||
| } | |||
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| void use_database(const string& name) | |||
| { | |||
| ddl_executor_t::get().switch_db_context(name); | |||
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I think there will be a problem if you have multiple threads using this (eg. multiple sessions)
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Not a problem for multiple threads because ddl_executor_t is a singleton and we use unique lock when switching context.
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I am not sure what you mean by multiple sessions. DB sessions are irrelevant here.
If you mean multiple processes, we always have the issue that the data structures in ddl_executor_t are not consistent across multiple processes.
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You have multiple threads, within the same process, each running their own session.
What happens if each of these threads to something that causes switch_db_context to be called?
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They will be executed in sequence due to the use of unique lock. The db context a statement see will be the last use statement before it. Remember DDLs are not subject to txn semantics. So we don't need to guarantee a consistent view for DDLs executed in parallel. More practically speaking, gaiac will not execute DDLs in parallel.
use databasestatement. With this, users can switch DB context in the DDL. Tables without a database name will be assumed in the current database context.gaiaccommand line usage in the following ways.create databaseDDL statement.create databasein the same DDL file.-d databasein the command line.For example,
gaiac -d barn_storage -d lab -g incubator.ddlwill generatebarn_storageandlabheaders underincubatordirectory.