NTP方式保证以时间戳同步可靠性

数据库同步的方式有设置标志位同步方式、以时间戳同步的方式，对于一对一的同步这两种方式都满足，但是对于一对多的同步，则只能选择时间戳的同步方式了，但是已时间戳同步的方式的一个问题是如何可靠的保证数据可以不丢失的同步到数据库中。下面有两种方式

数据库同步的方式有设置标志位同步方式、以时间戳同步的方式，对于一对一的同步这两种方式都满足，但是对于一对多的同步，则只能选择时间戳的同步方式了，但是已时间戳同步的方式的一个问题是如何可靠的保证数据可以不丢失的同步到数据库中。下面有两种方式来保证以时间戳同步的可靠性。

1、计算服务器与客户端两台电脑的时间差，将该时间差记入在同步时间的比对当中，下图是使用kettle做的一个计算同步的时间差的思路：

该思路的xml代码为：

<transformation><info><name>getLeadValue</name><description></description><extended_description></extended_description><trans_version></trans_version><trans_type>Normal</trans_type><trans_status>0</trans_status><directory>/downloadServerData/commonData</directory><parameters></parameters><log><trans-log-table><connection></connection><schema></schema><table></table>
<size_limit_lines></size_limit_lines><interval></interval><timeout_days></timeout_days><field><id>ID_BATCH</id><enabled>Y</enabled><name>ID_BATCH</name></field><field><id>CHANNEL_ID</id><enabled>Y</enabled><name>CHANNEL_ID</name></field><field><id>TRANSNAME</id><enabled>Y</enabled><name>TRANSNAME</name></field><field><id>STATUS</id><enabled>Y</enabled><name>STATUS</name></field><field><id>LINES_READ</id><enabled>Y</enabled><name>LINES_READ</name><subject></subject></field><field><id>LINES_WRITTEN</id><enabled>Y</enabled><name>LINES_WRITTEN</name><subject></subject></field><field><id>LINES_UPDATED</id><enabled>Y</enabled><name>LINES_UPDATED</name><subject></subject></field><field><id>LINES_INPUT</id><enabled>Y</enabled><name>LINES_INPUT</name><subject></subject></field><field><id>LINES_OUTPUT</id><enabled>Y</enabled><name>LINES_OUTPUT</name><subject></subject></field><field><id>LINES_REJECTED</id><enabled>Y</enabled><name>LINES_REJECTED</name><subject></subject></field><field><id>ERRORS</id><enabled>Y</enabled><name>ERRORS</name></field><field><id>STARTDATE</id><enabled>Y</enabled><name>STARTDATE</name></field><field><id>ENDDATE</id><enabled>Y</enabled><name>ENDDATE</name></field><field><id>LOGDATE</id><enabled>Y</enabled><name>LOGDATE</name></field><field><id>DEPDATE</id><enabled>Y</enabled><name>DEPDATE</name></field><field><id>REPLAYDATE</id><enabled>Y</enabled><name>REPLAYDATE</name></field><field><id>LOG_FIELD</id><enabled>Y</enabled><name>LOG_FIELD</name></field></trans-log-table><perf-log-table><connection></connection><schema></schema><table></table><interval></interval><timeout_days></timeout_days><field><id>ID_BATCH</id><enabled>Y</enabled><name>ID_BATCH</name></field><field><id>SEQ_NR</id><enabled>Y</enabled><name>SEQ_NR</name></field><field><id>LOGDATE</id><enabled>Y</enabled><name>LOGDATE</name></field><field><id>TRANSNAME</id><enabled>Y</enabled><name>TRANSNAME</name></field><field><id>STEPNAME</id><enabled>Y</enabled><name>STEPNAME</name></field><field><id>STEP_COPY</id><enabled>Y</enabled><name>STEP_COPY</name></field><field><id>LINES_READ</id><enabled>Y</enabled><name>LINES_READ</name></field><field><id>LINES_WRITTEN</id><enabled>Y</enabled><name>LINES_WRITTEN</name></field><field><id>LINES_UPDATED</id><enabled>Y</enabled><name>LINES_UPDATED</name></field><field><id>LINES_INPUT</id><enabled>Y</enabled><name>LINES_INPUT</name></field><field><id>LINES_OUTPUT</id><enabled>Y</enabled><name>LINES_OUTPUT</name></field><field><id>LINES_REJECTED</id><enabled>Y</enabled><name>LINES_REJECTED</name></field><field><id>ERRORS</id><enabled>Y</enabled><name>ERRORS</name></field><field><id>INPUT_BUFFER_ROWS</id><enabled>Y</enabled><name>INPUT_BUFFER_ROWS</name></field><field><id>OUTPUT_BUFFER_ROWS</id><enabled>Y</enabled><name>OUTPUT_BUFFER_ROWS</name></field></perf-log-table><channel-log-table><connection></connection><schema></schema><table></table>
<timeout_days></timeout_days><field><id>ID_BATCH</id><enabled>Y</enabled><name>ID_BATCH</name></field><field><id>CHANNEL_ID</id><enabled>Y</enabled><name>CHANNEL_ID</name></field><field><id>LOG_DATE</id><enabled>Y</enabled><name>LOG_DATE</name></field><field><id>LOGGING_OBJECT_TYPE</id><enabled>Y</enabled><name>LOGGING_OBJECT_TYPE</name></field><field><id>OBJECT_NAME</id><enabled>Y</enabled><name>OBJECT_NAME</name></field><field><id>OBJECT_COPY</id><enabled>Y</enabled><name>OBJECT_COPY</name></field><field><id>REPOSITORY_DIRECTORY</id><enabled>Y</enabled><name>REPOSITORY_DIRECTORY</name></field><field><id>FILENAME</id><enabled>Y</enabled><name>FILENAME</name></field><field><id>OBJECT_ID</id><enabled>Y</enabled><name>OBJECT_ID</name></field><field><id>OBJECT_REVISION</id><enabled>Y</enabled><name>OBJECT_REVISION</name></field><field><id>PARENT_CHANNEL_ID</id><enabled>Y</enabled><name>PARENT_CHANNEL_ID</name></field><field><id>ROOT_CHANNEL_ID</id><enabled>Y</enabled><name>ROOT_CHANNEL_ID</name></field></channel-log-table><step-log-table><connection></connection><schema></schema><table></table>
<timeout_days></timeout_days><field><id>ID_BATCH</id><enabled>Y</enabled><name>ID_BATCH</name></field><field><id>CHANNEL_ID</id><enabled>Y</enabled><name>CHANNEL_ID</name></field><field><id>LOG_DATE</id><enabled>Y</enabled><name>LOG_DATE</name></field><field><id>TRANSNAME</id><enabled>Y</enabled><name>TRANSNAME</name></field><field><id>STEPNAME</id><enabled>Y</enabled><name>STEPNAME</name></field><field><id>STEP_COPY</id><enabled>Y</enabled><name>STEP_COPY</name></field><field><id>LINES_READ</id><enabled>Y</enabled><name>LINES_READ</name></field><field><id>LINES_WRITTEN</id><enabled>Y</enabled><name>LINES_WRITTEN</name></field><field><id>LINES_UPDATED</id><enabled>Y</enabled><name>LINES_UPDATED</name></field><field><id>LINES_INPUT</id><enabled>Y</enabled><name>LINES_INPUT</name></field><field><id>LINES_OUTPUT</id><enabled>Y</enabled><name>LINES_OUTPUT</name></field><field><id>LINES_REJECTED</id><enabled>Y</enabled><name>LINES_REJECTED</name></field><field><id>ERRORS</id><enabled>Y</enabled><name>ERRORS</name></field><field><id>LOG_FIELD</id><enabled>N</enabled><name>LOG_FIELD</name></field></step-log-table></log><maxdate><connection></connection><table></table>
<field></field><offset>0.0</offset><maxdiff>0.0</maxdiff></maxdate><size_rowset>10000</size_rowset><sleep_time_empty>50</sleep_time_empty><sleep_time_full>50</sleep_time_full><unique_connections>N</unique_connections><feedback_shown>Y</feedback_shown><feedback_size>50000</feedback_size><using_thread_priorities>Y</using_thread_priorities><shared_objects_file></shared_objects_file><capture_step_performance>N</capture_step_performance><step_performance_capturing_delay>1000</step_performance_capturing_delay><step_performance_capturing_size_limit>100</step_performance_capturing_size_limit><dependencies></dependencies><partitionschemas></partitionschemas><slaveservers></slaveservers><clusterschemas></clusterschemas><created_user>-</created_user><created_date>2012/11/16 13:59:51.117</created_date><modified_user>-</modified_user><modified_date>2014/05/12 15:22:12.008</modified_date></info><notepads></notepads><connection><name>backupConn</name><server>${CLIENT_DATABASE_IP}</server><type>ORACLE</type><access>Native</access><database>${CLIENT_DATABASE_NAME}</database><port>${CLIENT_DATABASE_PORT}</port><username>${CLIENT_DATABASE_USERNAME}</username><password>${CLIENT_DATABASE_PASSWORD}</password><servername></servername><data_tablespace></data_tablespace><index_tablespace></index_tablespace><attributes><attribute><code>FORCE_IDENTIFIERS_TO_LOWERCASE</code><attribute>N</attribute></attribute><attribute><code>FORCE_IDENTIFIERS_TO_UPPERCASE</code><attribute>N</attribute></attribute><attribute><code>IS_CLUSTERED</code><attribute>N</attribute></attribute><attribute><code>PORT_NUMBER</code><attribute>${CLIENT_DATABASE_PORT}</attribute></attribute><attribute><code>QUOTE_ALL_FIELDS</code><attribute>N</attribute></attribute><attribute><code>SUPPORTS_BOOLEAN_DATA_TYPE</code><attribute>N</attribute></attribute><attribute><code>USE_POOLING</code><attribute>N</attribute></attribute></attributes></connection><connection><name>serverConn</name><server>${SERVER_DATABASE_IP}</server><type>ORACLE</type><access>Native</access><database>${SERVER_DATABASE_NAME}</database><port>${SERVER_DATABASE_PORT}</port><username>${SERVER_DATABASE_USERNAME}</username><password>${SERVER_DATABASE_PASSWORD}</password><servername></servername><data_tablespace></data_tablespace><index_tablespace></index_tablespace><attributes><attribute><code>FORCE_IDENTIFIERS_TO_LOWERCASE</code><attribute>N</attribute></attribute><attribute><code>FORCE_IDENTIFIERS_TO_UPPERCASE</code><attribute>N</attribute></attribute><attribute><code>IS_CLUSTERED</code><attribute>N</attribute></attribute><attribute><code>PORT_NUMBER</code><attribute>${SERVER_DATABASE_PORT}</attribute></attribute><attribute><code>QUOTE_ALL_FIELDS</code><attribute>N</attribute></attribute><attribute><code>SUPPORTS_BOOLEAN_DATA_TYPE</code><attribute>N</attribute></attribute><attribute><code>USE_POOLING</code><attribute>N</attribute></attribute></attributes></connection><connection><name>wardConn</name><server>${CLIENT_DATABASE_IP}</server><type>ORACLE</type><access>Native</access><database>${CLIENT_DATABASE_NAME}</database><port>${CLIENT_DATABASE_PORT}</port><username>${CLIENT_DATABASE_USERNAME}</username><password>${CLIENT_DATABASE_PASSWORD}</password><servername></servername><data_tablespace></data_tablespace><index_tablespace></index_tablespace><attributes><attribute><code>FORCE_IDENTIFIERS_TO_LOWERCASE</code><attribute>N</attribute></attribute><attribute><code>FORCE_IDENTIFIERS_TO_UPPERCASE</code><attribute>N</attribute></attribute><attribute><code>INITIAL_POOL_SIZE</code><attribute>50</attribute></attribute><attribute><code>IS_CLUSTERED</code><attribute>N</attribute></attribute><attribute><code>MAXIMUM_POOL_SIZE</code><attribute>500</attribute></attribute><attribute><code>PORT_NUMBER</code><attribute>${CLIENT_DATABASE_PORT}</attribute></attribute><attribute><code>QUOTE_ALL_FIELDS</code><attribute>N</attribute></attribute><attribute><code>SUPPORTS_BOOLEAN_DATA_TYPE</code><attribute>N</attribute></attribute><attribute><code>USE_POOLING</code><attribute>Y</attribute></attribute></attributes></connection><order><hop><from>增加常量</from><to>增加常量 2</to><enabled>Y</enabled></hop><hop><from>计算器</from><to>Set Variables 2</to><enabled>Y</enabled></hop><hop><from>调用DB存储过程</from><to>调用DB存储过程 2</to><enabled>Y</enabled></hop><hop><from>调用DB存储过程 2</from><to>增加常量</to><enabled>Y</enabled></hop><hop><from>增加常量 2</from><to>计算器</to><enabled>Y</enabled></hop></order><step><name>Set Variables 2</name><type>SetVariable</type><description></description><distribute>Y</distribute><copies>1</copies><partitioning><method>none</method><schema_name></schema_name></partitioning><fields><field><field_name>TIMEDIFF</field_name><variable_name>DOWNLOAD_SERVER_COMMON_DATA_LEAD</variable_name><variable_type>JVM</variable_type><default_value></default_value></field></fields><use_formatting>Y</use_formatting><cluster_schema></cluster_schema><remotesteps><input><output></output></remotesteps><gui><xloc>118</xloc><yloc>273</yloc><draw>Y</draw></gui></step><step><name>增加常量</name><type>Constant</type><description></description><distribute>Y</distribute><copies>1</copies><partitioning><method>none</method><schema_name></schema_name></partitioning><fields><field><name>DIVIDEND</name><type>Integer</type><format></format><currency></currency><decimal></decimal><group></group><nullif>86400000</nullif><length>-1</length><precision>-1</precision></field></fields><cluster_schema></cluster_schema><remotesteps><input><output></output></remotesteps><gui><xloc>388</xloc><yloc>241</yloc><draw>Y</draw></gui></step><step><name>增加常量 2</name><type>Constant</type><description></description><distribute>Y</distribute><copies>1</copies><partitioning><method>none</method><schema_name></schema_name></partitioning><fields><field><name>DEVIATION</name><type>Integer</type><format></format><currency></currency><decimal></decimal><group></group><nullif>10000</nullif><length>-1</length><precision>-1</precision></field></fields><cluster_schema></cluster_schema><remotesteps><input><output></output></remotesteps><gui><xloc>364</xloc><yloc>362</yloc><draw>Y</draw></gui></step><step><name>计算器</name><type>Calculator</type><description></description><distribute>Y</distribute><copies>1</copies><partitioning><method>none</method><schema_name></schema_name></partitioning><calculation><field_name>TEMP</field_name><calc_type>SUBTRACT</calc_type><field_a>LOCAL_DATE</field_a><field_b>SERVER_DATE</field_b><field_c></field_c><value_type>BigNumber</value_type><value_length>-1</value_length><value_precision>-1</value_precision><remove>N</remove><conversion_mask></conversion_mask><decimal_symbol></decimal_symbol><grouping_symbol></grouping_symbol><currency_symbol></currency_symbol></calculation><calculation><field_name>TEMP2</field_name><calc_type>ADD</calc_type><field_a>TEMP</field_a><field_b>DEVIATION</field_b><field_c></field_c><value_type>BigNumber</value_type><value_length>-1</value_length><value_precision>-1</value_precision><remove>N</remove><conversion_mask></conversion_mask><decimal_symbol></decimal_symbol><grouping_symbol></grouping_symbol><currency_symbol></currency_symbol></calculation><calculation><field_name>TIMEDIFF</field_name><calc_type>DIVIDE</calc_type><field_a>TEMP2</field_a><field_b>DIVIDEND</field_b><field_c></field_c><value_type>BigNumber</value_type><value_length>-1</value_length><value_precision>-1</value_precision><remove>N</remove><conversion_mask></conversion_mask><decimal_symbol></decimal_symbol><grouping_symbol></grouping_symbol><currency_symbol></currency_symbol></calculation><cluster_schema></cluster_schema><remotesteps><input><output></output></remotesteps><gui><xloc>251</xloc><yloc>272</yloc><draw>Y</draw></gui></step><step><name>调用DB存储过程</name><type>DBProc</type><description></description><distribute>Y</distribute><copies>1</copies><partitioning><method>none</method><schema_name></schema_name></partitioning><connection>serverConn</connection><procedure>F_GET_SYSDATE2INT</procedure><lookup></lookup><result><name>SERVER_DATE</name><type>BigNumber</type></result><auto_commit>Y</auto_commit><cluster_schema></cluster_schema><remotesteps><input><output></output></remotesteps><gui><xloc>140</xloc><yloc>134</yloc><draw>Y</draw></gui></step><step><name>调用DB存储过程 2</name><type>DBProc</type><description></description><distribute>Y</distribute><copies>1</copies><partitioning><method>none</method><schema_name></schema_name></partitioning><connection>wardConn</connection><procedure>F_GET_SYSDATE2INT</procedure><lookup></lookup><result><name>LOCAL_DATE</name><type>BigNumber</type></result><auto_commit>Y</auto_commit><cluster_schema></cluster_schema><remotesteps><input><output></output></remotesteps><gui><xloc>353</xloc><yloc>132</yloc><draw>Y</draw></gui></step><step_error_handling></step_error_handling><slave-step-copy-partition-distribution></slave-step-copy-partition-distribution><slave_transformation>N</slave_transformation></transformation>

2、通过NTP方式校对系统时间

1）如果可以连接到Internet网中，则可以采用国际上的校时服务器去校对时间

2）如果在内网中且不能上网，则可以自己定义一台都可访问到的台式机作为NTP服务器，其他机子与该计算机教士即可，下面是window NTP校时服务器的设置。

可以参考文章：NTP服务同步时间方案