Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
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The INNODB_LOCKS table contains information about each lock that an InnoDB transaction has requested but not yet acquired, and each lock that a
transaction holds that is blocking another transaction.
Table 20.5. INNODB_LOCKS Columns
| Column name | Description |
|---|---|
LOCK_ID |
Unique lock ID number, internal to InnoDB. Treat it as an opaque
string. Although LOCK_ID currently contains TRX_ID,
the format of the data in LOCK_ID is not guaranteed to remain the
same in future releases. Do not write programs that parse the LOCK_ID value.
|
LOCK_TRX_ID |
ID of the transaction holding this lock. Details about the transaction can be found by joining
with INNODB_TRX on TRX_ID.
|
LOCK_MODE |
Mode of the lock. One of S, X, IS, IX, S_GAP, X_GAP, IS_GAP,
IX_GAP, or AUTO_INC for shared,
exclusive, intention shared, intention exclusive row locks, shared and exclusive gap locks,
intention shared and intention exclusive gap locks, and auto-increment table level lock,
respectively. Refer to the sections Section 14.2.3.2,
"InnoDB Lock Modes" and Section
14.2.3.1, "The InnoDB Transaction Model and Locking" for
information on InnoDB locking.
|
LOCK_TYPE |
Type of the lock. One of RECORD or TABLE for record (row) level or table level locks, respectively.
|
LOCK_TABLE |
Name of the table that has been locked or contains locked records. |
LOCK_INDEX |
Name of the index if LOCK_TYPE='RECORD', otherwise NULL.
|
LOCK_SPACE |
Tablespace ID of the locked record if LOCK_TYPE='RECORD', otherwise
NULL.
|
LOCK_PAGE |
Page number of the locked record if LOCK_TYPE='RECORD', otherwise
NULL.
|
LOCK_REC |
Heap number of the locked record within the page if LOCK_TYPE='RECORD', otherwise NULL.
|
LOCK_DATA |
Primary key of the locked record if LOCK_TYPE='RECORD', otherwise
NULL. This column contains the value(s) of the primary key
column(s) in the locked row, formatted as a valid SQL string (ready to be copied to SQL
commands). If there is no primary key then the InnoDB internal
unique row ID number is used. When the page containing the locked record is not in the buffer
pool (in the case that it was paged out to disk while the lock was held), InnoDB
does not fetch the page from disk, to avoid unnecessary disk operations. Instead, LOCK_DATA is set toNULL.
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Notes:
Use this table to help diagnose performance problems that occur during times of
heavy concurrent load. Its contents are updated as described in Section
14.2.4.3.4.2, "Granularity of INFORMATION_SCHEMA Data".
You must have the PROCESS privilege to query this
table.
For usage information, see Section 14.2.4.3.2.1, "Using the Transaction Information Schema Tables".