This section contains information about additional query parameters. For more information about commands, see the Commands section.
Here is a list of the commands for which you can specify success conditions:
There are two types of conditions:
prerequisite_revisions: A set of hints including
revision. The query will be executed only if all the paths provided in the hint exist (in the context of the given transactions) and the revisions are as hinted.
prerequisite_transactionsincludes a list of transactions that must exist when the query is executed.
revision = client.get("//tmp/my_table/@revision") #... some calculations ... revision_parameter = yt.create_revision_parameter(path="//tmp/my_table", revision=revision) revision_client = yt.create_client_with_command_params(prerequisite_revisions=[revision_parameter]) revision_client.move("//tmp/transformed_table", "//tmp/my_table")
Data source for reading
A popular value for the
read_from parameter is
cache. In this case, the response is read from the cache (usually hosted on dedicated instances in the cluster). This allows decreasing the load on the master server. This is important when running numerous heavy queries against Cypress: for example, if you need to traverse a large subtree.
for obj in client.search("//tmp/my_table", read_from="cache"): if "abc" in str(obj): ...