<p>One strategy to deal with data type changes is outlined in the following blog posts:</p>
<p>Instead of "Change the type of a column", " Add a new column, change the code to write to both columns, and backfill the new column".</p>
<ul>
<li><a href="https://jilt.com/blog/migrations-zero-downtime-rails/" rel="nofollow">https://jilt.com/blog/migrations-zero-downtime-rails/</a></li>
<li><a href="https://www.braintreepayments.com/blog/safe-operations-for-high-volume-postgresql/" rel="nofollow">https://www.braintreepayments.com/blog/safe-operations-for-high-volume-postgresql/</a></li>
</ul>
<p>For sure that's more effort, it all depends a bit on how long a read only or offline periods may take at most.</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br />You are receiving this because you are subscribed to this thread.<br />Reply to this email directly, <a href="https://github.com/openstreetmap/openstreetmap-website/issues/2076#issuecomment-442853014">view it on GitHub</a>, or <a href="https://github.com/notifications/unsubscribe-auth/ABWnLcZOjJ8eqAD6CW_TvlSXWgJpheJrks5uz-8dgaJpZM4Y4AnY">mute the thread</a>.<img src="https://github.com/notifications/beacon/ABWnLVrzf_Fz20gx7v5cm1U-FG4uh4_Qks5uz-8dgaJpZM4Y4AnY.gif" height="1" width="1" alt="" /></p>
<script type="application/json" data-scope="inboxmarkup">{"api_version":"1.0","publisher":{"api_key":"05dde50f1d1a384dd78767c55493e4bb","name":"GitHub"},"entity":{"external_key":"github/openstreetmap/openstreetmap-website","title":"openstreetmap/openstreetmap-website","subtitle":"GitHub repository","main_image_url":"https://assets-cdn.github.com/images/email/message_cards/header.png","avatar_image_url":"https://assets-cdn.github.com/images/email/message_cards/avatar.png","action":{"name":"Open in GitHub","url":"https://github.com/openstreetmap/openstreetmap-website"}},"updates":{"snippets":[{"icon":"PERSON","message":"@mmd-osm in #2076: One strategy to deal with data type changes is outlined in the following blog posts:\r\n\r\nInstead of \"Change the type of a column\", \" Add a new column, change the code to write to both columns, and backfill the new column\".\r\n\r\n* https://jilt.com/blog/migrations-zero-downtime-rails/\r\n* https://www.braintreepayments.com/blog/safe-operations-for-high-volume-postgresql/\r\n\r\nFor sure that's more effort, it all depends a bit on how long a read only or offline periods may take at most.\r\n"}],"action":{"name":"View Issue","url":"https://github.com/openstreetmap/openstreetmap-website/issues/2076#issuecomment-442853014"}}}</script>
<script type="application/ld+json">[
{
"@context": "http://schema.org",
"@type": "EmailMessage",
"potentialAction": {
"@type": "ViewAction",
"target": "https://github.com/openstreetmap/openstreetmap-website/issues/2076#issuecomment-442853014",
"url": "https://github.com/openstreetmap/openstreetmap-website/issues/2076#issuecomment-442853014",
"name": "View Issue"
},
"description": "View this Issue on GitHub",
"publisher": {
"@type": "Organization",
"name": "GitHub",
"url": "https://github.com"
}
},
{
"@type": "MessageCard",
"@context": "http://schema.org/extensions",
"hideOriginalBody": "false",
"originator": "AF6C5A86-E920-430C-9C59-A73278B5EFEB",
"title": "Re: [openstreetmap/openstreetmap-website] Partition large tables (#2076)",
"sections": [
{
"text": "",
"activityTitle": "**mmd**",
"activityImage": "https://assets-cdn.github.com/images/email/message_cards/avatar.png",
"activitySubtitle": "@mmd-osm",
"facts": [

]
}
],
"potentialAction": [
{
"name": "Add a comment",
"@type": "ActionCard",
"inputs": [
{
"isMultiLine": true,
"@type": "TextInput",
"id": "IssueComment",
"isRequired": false
}
],
"actions": [
{
"name": "Comment",
"@type": "HttpPOST",
"target": "https://api.github.com",
"body": "{\n\"commandName\": \"IssueComment\",\n\"repositoryFullName\": \"openstreetmap/openstreetmap-website\",\n\"issueId\": 2076,\n\"IssueComment\": \"{{IssueComment.value}}\"\n}"
}
]
},
{
"name": "Close issue",
"@type": "HttpPOST",
"target": "https://api.github.com",
"body": "{\n\"commandName\": \"IssueClose\",\n\"repositoryFullName\": \"openstreetmap/openstreetmap-website\",\n\"issueId\": 2076\n}"
},
{
"targets": [
{
"os": "default",
"uri": "https://github.com/openstreetmap/openstreetmap-website/issues/2076#issuecomment-442853014"
}
],
"@type": "OpenUri",
"name": "View on GitHub"
},
{
"name": "Unsubscribe",
"@type": "HttpPOST",
"target": "https://api.github.com",
"body": "{\n\"commandName\": \"MuteNotification\",\n\"threadId\": 417335768\n}"
}
],
"themeColor": "26292E"
}
]</script>