G
George Potemkin
Guest
Question: Which blocks can be locked by a session at the same time? Answer (based on the results of two atm tests): 1) Exclusive lock of Object block + Exclusive lock of Data block 2) Data block in disk I/O state ("R" in the "S" column) + one or more Share/Exclusive locks of Index blocks. All index blocks belong to the same index. The index can belong to a table other than the table that owns the data block. 3) A few Index blocks that belong to the same index. The lock on the first block can have any status: S Share Lock I Share Lock with Intent to modify. X Exclusive Lock R I/O state (either being read or written) The blocks are locked in the order as specified (or in the reverse order ;-). Results of the tests are attached. Objects per areas: Area Table/Index 7 account 8 branch 9 client 10 config 11 history1 12 history2 13 history3 14 history4 15 results 16 teller -- --------------- 17 account.account 18 branch.branch 19 client.id 20 config.id 21 history1.histid 22 history2.histid 23 history3.histid 24 history4.histid 25 results.id 26 teller.teller Results: (Please visit the site to view this file) (Please visit the site to view this file)
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