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WL#4078: Document binary format of binlog entries

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Minor update with corrections and notes on the binlog format.
This only affects comments, not code.


sql/log_event.h:
  Fixes in documentation of binlog format.
This commit is contained in:
unknown 2008-02-20 14:52:21 +01:00
parent 5d1e8e12c3
commit 6988f45e6b
1 changed files with 26 additions and 20 deletions
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46
sql/log_event.h
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@ -670,18 +670,18 @@ typedef struct st_print_event_info
Any @c Log_event saved on disk consists of the following three Any @c Log_event saved on disk consists of the following three
components. components.
* Common-Header - Common-Header
* Post-Header - Post-Header
* Body - Body
The Common-Header, documented in the table @ref Table_common_header The Common-Header, documented in the table @ref Table_common_header
"below", always has the same form and length within one version of "below", always has the same form and length within one version of
MySQL. Each event type specifies a form and length of the MySQL. Each event type specifies a format and length of the
Post-Header common to all events of the type. The Body may be of Post-Header. The length of the Common-Header is the same for all
different form and length even for different events of the same events of the same type. The Body may be of different format and
type. The binary formats of Post-Header and Body are documented length even for different events of the same type. The binary
separately in each subclass. The binary format of Common-Header is formats of Post-Header and Body are documented separately in each
as follows. subclass. The binary format of Common-Header is as follows.
<table> <table>
<caption>Common-Header</caption> <caption>Common-Header</caption>
@ -750,8 +750,8 @@ typedef struct st_print_event_info
- Some events use a special format for efficient representation of - Some events use a special format for efficient representation of
unsigned integers, called Packed Integer. A Packed Integer has the unsigned integers, called Packed Integer. A Packed Integer has the
capacity of storing up to 8-byte integers, while small integers capacity of storing up to 8-byte integers, while small integers
still can use 1, 3, or 4 bytes. The first byte indicates how many still can use 1, 3, or 4 bytes. The value of the first byte
bytes are used by the integer, according to the following table: determines how to read the number, according to the following table:
<table> <table>
<caption>Format of Packed Integer</caption> <caption>Format of Packed Integer</caption>
@ -763,7 +763,7 @@ typedef struct st_print_event_info
<tr> <tr>
<td>0-250</td> <td>0-250</td>
<td>The first byte is the number (in range 0-250), and no more <td>The first byte is the number (in the range 0-250), and no more
bytes are used.</td> bytes are used.</td>
</tr> </tr>
@ -1174,6 +1174,10 @@ protected:
@section Query_log_event_binary_format Binary format @section Query_log_event_binary_format Binary format
See @ref Log_event_binary_format "Binary format for log events" for
a general discussion and introduction to the binary format of binlog
events.
The Post-Header has five components: The Post-Header has five components:
<table> <table>
@ -1407,7 +1411,7 @@ protected:
query "SELECT id, character_set_name, collation_name FROM query "SELECT id, character_set_name, collation_name FROM
COLLATIONS". COLLATIONS".
Cf. Q_CHARSET_DATABASE_NUMBER below. Cf. Q_CHARSET_DATABASE_CODE below.
This field is always written. This field is always written.
</td> </td>
@ -1442,7 +1446,7 @@ protected:
<tr> <tr>
<td>charset_database_number</td> <td>charset_database_number</td>
<td>Q_CHARSET_DATABASE_NUMBER == 8</td> <td>Q_CHARSET_DATABASE_CODE == 8</td>
<td>2 byte integer</td> <td>2 byte integer</td>
<td>The value of the collation_database system variable (in the <td>The value of the collation_database system variable (in the
@ -1457,11 +1461,11 @@ protected:
In newer versions, "CREATE TABLE" has been changed to take the In newer versions, "CREATE TABLE" has been changed to take the
character set from the database of the created table, rather than character set from the database of the created table, rather than
the database of the current database. This makes a difference the character set of the current database. This makes a
when creating a table in another database than the current one. difference when creating a table in another database than the
"LOAD DATA INFILE" has not yet changed to do this, but there are current one. "LOAD DATA INFILE" has not yet changed to do this,
plans to eventually do it, and to make collation_database but there are plans to eventually do it, and to make
read-only. collation_database read-only.
This field is written if it is not 0. This field is written if it is not 0.
</td> </td>
@ -1480,7 +1484,7 @@ protected:
Q_CATALOG_CODE will never be written by a new master, but can still Q_CATALOG_CODE will never be written by a new master, but can still
be understood by a new slave. be understood by a new slave.
* See Q_CHARSET_DATABASE_NUMBER in the table above. * See Q_CHARSET_DATABASE_CODE in the table above.
*/ */
class Query_log_event: public Log_event class Query_log_event: public Log_event
@ -1919,6 +1923,8 @@ private:
@subsection Load_log_event_notes_on_previous_versions Notes on Previous Versions @subsection Load_log_event_notes_on_previous_versions Notes on Previous Versions
This event type is understood by current versions, but only
generated by MySQL 3.23 and earlier.
*/ */
class Load_log_event: public Log_event class Load_log_event: public Log_event
{ {