Portal getting slow/down frequently

Issue

• Liferay portal gets too slow or down frequently and below threads are observed in the thread dumps:
  

  at java.util.regex.Pattern$BnM.match(Pattern.java:5483)
  at java.util.regex.Matcher.search(Matcher.java:1248)
  at java.util.regex.Matcher.find(Matcher.java:637)
  at com.liferay.adaptive.media.content.transformer.BaseRegexStringContentTransformer.transform(BaseRegexStringContentTransformer.java:46)
  at com.liferay.adaptive.media.image.content.transformer.backwards.compatibility.internal.AMBackwardsCompatibilityHtmlContentTransformer.transform(AMBackwardsCompatibilityHtmlContentTransformer.java:70)
  at com.liferay.adaptive.media.image.content.transformer.backwards.compatibility.internal.AMBackwardsCompatibilityHtmlContentTransformer.transform(AMBackwardsCompatibilityHtmlContentTransformer.java:41)

• Above long running threads contains AMBackwardsCompatibilityHtmlContentTransformer class.

Environment

• Liferay DXP 7.2
• Liferay DXP 7.3

Resolution

• The observed behavior is a known bug and is being addressed via LPS-148916 and resolved in DXP 7.3 U4.
• In case user needs further info regarding the LPS, please create a help center ticket mentioning the provided LPS.