mirror of https://github.com/zulip/zulip.git
28 lines
920 B
Python
28 lines
920 B
Python
from typing import Any, Callable, Dict, List, Tuple
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from django.db.models.query import QuerySet
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import re
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import time
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def create_index_if_not_exist(index_name: str, table_name: str, column_string: str,
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where_clause: str) -> str:
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#
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# FUTURE TODO: When we no longer need to support postgres 9.3 for Trusty,
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# we can use "IF NOT EXISTS", which is part of postgres 9.5
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# (and which already is supported on Xenial systems).
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stmt = '''
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DO $$
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BEGIN
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IF NOT EXISTS (
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SELECT 1
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FROM pg_class
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where relname = '%s'
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) THEN
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CREATE INDEX
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%s
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ON %s (%s)
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%s;
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END IF;
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END$$;
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''' % (index_name, index_name, table_name, column_string, where_clause)
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return stmt
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