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<td class="text-paragraph-pattern-container mobile-resize-text " style="padding: 0px; border-collapse: collapse; padding: 0 0 10px 0"> <p style="margin: 10px 0 0 0; margin-top: 0">Maybe we can try the Twitter-Snowflake? It can help generate unique IDs. And it only requires 64 bits. Also,it's self-increasing(so it's friendly with data insertion). The 64 bit is a composition of: timestamp, worker number and sequence number. <br> 0(1 bit: don't use)<br> -000...000(41 bits: timestamp)<br> -000...000(10 bits: worker number)<br> -000...000(12 bits: sequence number). <br> The 41-bit timestamp can support the algorithm till year 2082. The 10-bit worker number can support 1023 workers. The sequence number supports producing 4095 self-increasing sequence ids in every ms. </p> <p style="margin: 10px 0 0 0">code for timestamp:<br> uint64_t generateStamp()</p> { timeval tv; gettimeofday(&tv, 0); return (uint64_t)tv.tv_sec * 1000 + (uint64_t)tv.tv_usec / 1000; } <p style="margin: 10px 0 0 0">code for sequence number:<br> uint64_t waitNextMs(uint64_t lastStamp)<br> {<br> uint64_t cur = 0;<br> do </p> { cur = generateStamp(); } <p style="margin: 10px 0 0 0"> while (cur <= lastStamp);<br> return cur;<br> }</p> <p style="margin: 10px 0 0 0">reference: <a href="https://github.com/twitter/snowflake" class="external-link" rel="nofollow" style="color: #3b73af; text-decoration: none">https://github.com/twitter/snowflake</a></p> </td>
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