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Zendesk's Maxwell Compatibility (#119)

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* Binlog router: Introduce maxwell_compatibility flag

* Binlog router: Handle 'server vars' query

This is a step towards using MaxScale with Zendesk's Maxwell.

* Binlog router: Handle results charset query

* Binlog router: Handle sql_mode query

* Binlog router: Handle server_id query

* Binlog router: Handle 'binlog vars' queries

* Binlog router: Handle @@lower_case_table_names query

* Binlog router: Handle @@global.binlog_checksum query

* Binlog router: DRY Maxwell SQL queries
This commit is contained in:
Adam Szkoda
2017-02-13 16:40:01 +01:00
committed by MassimilianoPinto
parent fdc66c660c
commit 825782799f
6 changed files with 300 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

112
server/modules/routing/binlogrouter/blr_slave.c
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@ -282,6 +282,46 @@ blr_slave_request(ROUTER_INSTANCE *router, ROUTER_SLAVE *slave, GWBUF *queue)
return 0;
}
/*
* Return a pointer to where the actual SQL query starts, skipping initial
* comments and whitespace characters, if there are any.
*/
const char *
blr_skip_leading_sql_comments(const char *sql_query)
{
const char *p = sql_query;
while (*p) {
if (*p == '/' && p[1] == '*')
{
++p; // skip '/'
++p; // skip '*'
while (*p)
{
if (*p == '*' && p[1] == '/')
{
++p; // skip '*'
++p; // skip '/'
break;
}
else
{
++p;
}
}
}
else if (isspace(*p))
{
++p;
}
else
{
return p;
}
}
return p;
}
/**
* Handle a query from the slave. This is expected to be one of the "standard"
* queries we expect as part of the registraton process. Most of these can
@ -350,6 +390,13 @@ blr_slave_query(ROUTER_INSTANCE *router, ROUTER_SLAVE *slave, GWBUF *queue)
char *ptr;
extern char *strcasestr();
bool unexpected = true;
static const char mysql_connector_results_charset_query[] = "SET character_set_results = NULL";
static const char maxwell_server_id_query[] = "SELECT @@server_id as server_id";
static const char maxwell_log_bin_query[] = "SHOW VARIABLES LIKE 'log_bin'";
static const char maxwell_binlog_format_query[] = "SHOW VARIABLES LIKE 'binlog_format'";
static const char maxwell_binlog_row_image_query[] = "SHOW VARIABLES LIKE 'binlog_row_image'";
static const char maxwell_lower_case_tables_query[] = "select @@lower_case_table_names";
qtext = (char*)GWBUF_DATA(queue);
query_len = extract_field((uint8_t *)qtext, 24) - 1;
@ -396,7 +443,68 @@ blr_slave_query(ROUTER_INSTANCE *router, ROUTER_SLAVE *slave, GWBUF *queue)
* own interaction with the real master. We simply replay these saved responses
* to the slave.
*/
if ((word = strtok_r(query_text, sep, &brkb)) == NULL)
if (strcmp(blr_skip_leading_sql_comments(query_text), MYSQL_CONNECTOR_SERVER_VARS_QUERY) == 0)
{
int rc = blr_slave_replay(router, slave, router->saved_master.server_vars);
if (rc >= 0)
{
MXS_FREE(query_text);
return 1;
}
MXS_ERROR("Error sending mysql-connector-j server variables");
}
else if (router->maxwell_compat && strcmp(query_text, mysql_connector_results_charset_query) == 0)
{
MXS_FREE(query_text);
return blr_slave_send_ok(router, slave);
}
else if (router->maxwell_compat && strcmp(query_text, MYSQL_CONNECTOR_SQL_MODE_QUERY) == 0)
{
MXS_FREE(query_text);
return blr_slave_send_ok(router, slave);
}
else if (strcmp(query_text, maxwell_server_id_query) == 0)
{
char server_id[40];
sprintf(server_id, "%d", router->masterid);
MXS_FREE(query_text);
return blr_slave_send_var_value(router, slave, "server_id", server_id, BLR_TYPE_STRING);
}
else if (strcmp(query_text, maxwell_log_bin_query) == 0)
{
char *log_bin = blr_extract_column(router->saved_master.binlog_vars, 1);
blr_slave_send_var_value(router, slave, "Value", log_bin == NULL ? "" : log_bin, BLR_TYPE_STRING);
MXS_FREE(log_bin);
MXS_FREE(query_text);
return 1;
}
else if (strcmp(query_text, maxwell_binlog_format_query) == 0)
{
char *binlog_format = blr_extract_column(router->saved_master.binlog_vars, 2);
blr_slave_send_var_value(router, slave, "Value", binlog_format == NULL ? "" : binlog_format, BLR_TYPE_STRING);
MXS_FREE(binlog_format);
MXS_FREE(query_text);
return 1;
}
else if (strcmp(query_text, maxwell_binlog_row_image_query) == 0)
{
char *binlog_row_image = blr_extract_column(router->saved_master.binlog_vars, 1);
blr_slave_send_var_value(router, slave, "Value", binlog_row_image == NULL ? "" : binlog_row_image, BLR_TYPE_STRING);
MXS_FREE(binlog_row_image);
MXS_FREE(query_text);
return 1;
}
else if (strcmp(query_text, maxwell_lower_case_tables_query) == 0)
{
int rc = blr_slave_replay(router, slave, router->saved_master.lower_case_tables);
if (rc >= 0)
{
MXS_FREE(query_text);
return 1;
}
MXS_ERROR("Error sending lower_case_tables query response");
}
else if ((word = strtok_r(query_text, sep, &brkb)) == NULL)
{
MXS_ERROR("%s: Incomplete query.", router->service->name);
}
@ -411,7 +519,7 @@ blr_slave_query(ROUTER_INSTANCE *router, ROUTER_SLAVE *slave, GWBUF *queue)
MXS_FREE(query_text);
return blr_slave_send_timestamp(router, slave);
}
else if (strcasecmp(word, "@master_binlog_checksum") == 0)
else if (strcasecmp(word, "@master_binlog_checksum") == 0 || strcasecmp(word, "@@global.binlog_checksum") == 0)
{
MXS_FREE(query_text);
return blr_slave_replay(router, slave, router->saved_master.chksum2);